Ship-mounted rafting device for sea ice habitat restoration

Abstract

A sea ice habitat restoration system is configured to rapidly extract pack ice and raft it onto level ice to establish disturbance corridors that augment the ecological carrying capacity and resistance to continuing climate change. The deployable system is configured to be mounted on an icebreaking ship and includes a inclined-plane ice ramp supported by an ice rafting device. The system applies a hogging moment to the extracted sea ice and laterally rafts it with minimal damage, facilitating the restoration of sea ice habitats of threatened ice-obligate and ice-associated species. This ship-mounted version produces significantly greater volumes, additional vertically and horizontally arranged layers, and more widely distributed composite masses of freeze-bonded rafted ice over the course of a w inter compared to the singly rafted ice passively produced by the moored version referenced herein.

Description

TITLE OF THE INVENTIONSHIP-MOUNTED RAFTING DEVICE FOR SEA ICE HABITAT RESTORATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The entire disclosure of International Application No. PCT / US2022 / 049700, published as W02024 / 102140, is incorporated into the present application by reference.TECHNICAL FIELD

[0002] The invention relates to a system and method for restoring sea ice habitats by manipulating pack ice using an icebreaking ship equipped with a specialized ice ramp. As noted in PCT / US2022 / 49700, the application to which the present application claims priority, the rafted and freeze-bonded Arctic pack ice produced as disclosed therein may not survive through summer melt due to inadequate thickness and continued warming from climate change. A ship-mounted sea ice habitat restoration system may produce significantly greater volumes, additional vertically or horizontally arranged layers, and more widely distributed composite masses of freeze-bonded rafted ice over the course of a winter, providing higher likelihood of use by the species discussed herein, and of achieving multiyear durability as compared to singly rafted ice passively produced by a moored platform.BACKGROUND

[0003] Due to climate change, the extent and thickness of Arctic sea ice is decreasing and during summer disappears from marine habitat over shelf waters in the Bering. Chukchi. Beaufort, East Siberian, Laptev, Kara and Barents Seas (Kwok et al., 2009; Stroeve et al. 2014, p. 1216). Seasonal (first year or FY) ice has replaced multiyear (MY) ice as the dominant ty pe since the 1990s (Perovich et al., 2019, Fig. 3). In the period between autumn freeze-up and spring break-up. which continues to shorten, the FY ice that does form is declining in thickness due to declining freezing degree days (FDD), and to warming of seasurface temperatures during open water season (Anderson, 1961; Stroeve et al., 2018, Fig. 2c). A related problem with thinner level ice is that it melts sooner than thicker level ice due in part to increased surface-to-volume ratio and is more prone to break-up (Bilello, 1980, pp.29-34). Thus, the decline in Arctic pack ice habitat extent, durability, and carrying capacity as a platform, shelter and substrate threatens the survival of countless native species that the ice has supported for hundreds of thousands of years (Worsley and Herman, 1980).

[0004] With the foregoing context, in order to maintain some remnants of pack ice habitat for the aforementioned ice-obligate and ice-associated species (Moore and Huntington, 2008, p. S158-S159; Tynan et al., 2010, p. 395-396) including walrus, pagophilic phocid seals, polar bears, Arctic fox, Arctic cod (Boreogadus saida), spectacled eider, ivory gulls, thickbilled murres and black guillemots, a habitat restoration rafting device and method in accordance with some preferred embodiments may produce a pack ice disturbance patch and corndor with increased ice thickness, load capacity, durability, lair-making opportunities, enhanced sea ice derived primary production from ice algae, increased spatial distribution of rafted ice via drifting after ice break-up in spring, and enhanced organic carbon flux to the benthos (Pickett and White, 1985, pp. 3-13; Forman and Godron, 1986. pp. 83-155;Grebmeier and Barry, 2007, pp. 363-365; Ray and McCormick-Ray, 2014. pp. 129-132).ECOSYSTEM AND LANDSCAPE ECOLOGY CONTEXT

[0005] As it implies, the term "patch’, from the field of landscape ecology, indicates an area of habitat and its native community of species set within an overall ecosystem - the ‘matrix’ - that is typically less supportive and possibly hostile or fatal to some members of the community (Pickett and White, 1985, pp. 4-5). ‘Corridor’ indicates a curvilinear patch that allows community member dispersal between patches, and a group of patches in the matrix may be linked together with a system of corridors. A corridor might be the result of natural biotic and abiotic processes over hundreds of thousands of years, as in the case of a river and riparian ecosystem formed by a confluence of rainfall, snowmelt, ground water, freeze-thaw, faunal and floral temporal succession, and other biogeochemical processes (Hilty et al., 2006, pp. 50, 200-201). Examples of ‘disturbance’ patches and 'disturbance’ corridors include an isolated area of forest severely burned due to a lightning strike and juststarting to be recolonized by pioneer species, a cleared strip through forest for a powerline (Forman and Godron, 1986, p. 143), or a wetland emerging over decades upstream of a beaver dam in a forest (Johnston and Naiman, 1987, pp. 47-50). It is suggested that the ongoing anthropogenic pulse of greenhouse gas emissions beginning approximately with the Industrial Revolution is an example of a global disturbance with what is projected to be a duration of centuries to thousands of years depending on the effect under consideration (Pickett and White, 1985, pp. 6-13; Solomon et al., 2009). It would probably be classified at the ‘catastrophic’ level of disturbance using the definition according to J. L. Harper (1977, p.627; Pickett and White, 1985 p. 8), since it tends to decrease fitness given the brief geologic time span and frequency permitted for adaptation, particularly for long-lived K-selected species like semi-aquatic marine mammals. Thus, disturbances come in a wide variety’ and do not necessarily correlate with a net loss of diversity', abundance or other long term ecosystem damage, and intermediate disturbance theory suggests that a maximum diversity’ and abundance tend to occur with some moderate level of disturbance with respect to its frequency, duration, magnitude and severity’, so that all community members have opportunity’ to recover, redistribute, compete, and potentially accrue increased fitness due to the natural selection processes generated by the disturbance (Sousa, pp. 120-121; Pickett and White, 378-379).

[0006] In the case of the sea ice habitat restoration systems and methods disclosed herein, mechanically forcing ice to the sides creates a disturbance in the recurring pattern of the pack ice matrix. The resulting aquatic disturbance patch - a continually moving opening in the ice flanked on each side by rafted ice - transitions to a disturbance corridor of rafted ice and ephemeral open water that begins to freeze given sufficient FDD thereafter (Hilty et al., 2006, pp. 89, 116). This aquatic disturbance patch in the pack ice matrix opens multiple, pathways for species to move: 1) across the plane of the water surface, and 2) through the surface into the water column, to bottom ice habitat, to remote breathing holes and possibly lairs, to openings in the corridor further downdrift, to cracks and openings in the ice formed by neighboring ship-mounted rafting devices or moored rafting platforms, and down to the benthos and back.

[0007] The term ‘pack ice’ or just ‘pack’ used throughout this disclosure indicates all types of sea ice that is not landfast. While some prefer to reserve the term ‘pack ice’ for driftsea ice that is above a certain percent areal coverage, e.g., 70%, that is not its meaning here. The preferred location for a habitat restoration site is in shelf waters up to about 70 m depth since the approximate, most commonly observed diving limit of the spectacled eider is about 70 m and that of walrus about 80 m (Fay, 1982, p. 163; USFWS, 1994, p. 6), limits which are generally shallower than that of pagophilic phocid seals. Contrary to ice-obligate and ice associated species, some seasonally migrant cetaceans (e.g., fin whales, gray, minke and killer whales) may be positively affected by increased ranges made possible by ice loss (Moore and Huntington, 2008, p. S158). The pack ice restoration provided by a group of ship-mounted rafting devices or an array of moored platforms will not provide enough ice to even modestly reduce invasion by seasonally migrant species such as killer whales, which are known to prey on and at times compete with native species.

[0008] As to some specifics of the rafting process, the artificial rafting induced by the habitat restoration ship-mounted rafting device - as distinct from naturally occurring rafting -simultaneously exposes an area of open water of comparable width between the two parallel rafted zones (Shirasawa et al., 2009, pp. 1182, 1198; Weeks, 2010, p. 336). By redirecting ice drift forces up the ramps, a strip of pack ice is extracted by shearing and application of a hogging moment which cracks the ice under its own weight, generally in flexure, and deposits it laterally onto the passing pack ice to form through freeze-bonding a consolidated, rafted ice approximately twice the extracted ice thickness, and with nearly the same and possibly greater strength upon full freeze-bonding as comparably thick monolithic ice (Jizu et al., 1991, p. 761; Bailey et al., 2010, p. 2). Given sufficient pack ice thickness (some of which may already have been naturally rafted), rafted ice created with this process may support the loads of the aforementioned species, increase pack ice durability and drift range, extend sea-ice derived primary production, enhance the flux of nutrients into the w ater column and eventually to the benthos (Moore and Huntington, 2008, p. S158; Ray and McCormick-Ray, 2014, p. 179).Translucent Aquifer - Comparison with Flood Basalt

[0009] Sea ice is quite unlike manufactured ice, including that found in spray ice or flood ice islands historically employed in the Arctic, or even lake ice. To provide some insight into its structure, complex relationship to the species that have evolved with it, and betterunderstand aspects of the ship-mounted device’s effects described further below, it is suggested to imagine pack ice as a translucent, cemented soil or weathered, porous rock profile which shares qualities with more familiar terrestrial formations, which have accumulated a much larger and richer body of human experience, culture, and scientific and engineering literature. The analog suggested and described briefly below is flood basalt - a type of lava formation found around the world, notably in Siberia, Washington State, and west central India, as well as on other planets including the Moon and Mars (McMahon et al., 2013, p. 1.20, Fig. 3A and 3B). This particular flood basalt is assumed to be transformed over time into an unconfmed aquifer (i.e., a water-bearing and transmitting porous material such as rock, gravel or sand open to atmospheric pressure), in this case with a groundwater table fluctuating just below the surface to align with the freeboard condition of pack ice in seawater. As far as hypothetically considering pack ice as a ty pe of aquifer or at least in many respects being the functional equivalent, saline aquifers certainly exist around the world, and to demonstrate the suggestion is not too contrived, consider some properties and processes in parallel below.

[0010] On a molecular scale, the microstructure of sea ice is composed of water molecules knit together with hydrogen bonds into 3D lattices of hexagonal cells (type Ih ice; Petrich and Eichen, 2010, p.26), while basalt is a mixture of silica and other minerals arranged into more complex lattices with covalent and ionic bonds on the order of ten times or more the strength (Weeks, 2010, p. 54). This difference in bond energy is the basis of the relatively low melting point of sea ice. initially about -1.8°C at a typical 32-35%o parent seawater salinity compared to the 1000-1200°C of many basalts, though during summer melting it may rise to around 0°C as further brine drainage produces more purified ice (Bilello, 1980 p. 28). Since the upper surface temperature of Arctic pack ice only falls to around -20 to -40°C for extended periods in winter, with the bottom surface of level pack often remaining around -1.8°C, pack ice survival is confined to a seasonally shifting gradient of only 2 to 38°C. (Considering that the IPCC Sixth Assessment Report projects a global average surface temperature rise of 1.5°C with respect to a baseline average for 1850-1900 as soon as the early 2030s with an amplification factor for polar regions roughly twice the global average, the increase of roughly 3°C narrows its range still further (Melnikov, 1997; pp.31-33; Arias et al., 2021)).

[0011] While their bond energies and hence solid phase thermal ranges are quite different, the top-down crystallization of seawater generates a pack ice stratigraphy reminiscent of many flood basalts, that when thick enough and cooled slowly enough, undergo differentiation into a three layered macrostructure. The top layer of frazil ice with its jumbled, porous microstructure of crystalline needles and disks solidifies first, resembling the similarly nonuniform and porous top layer of cooling lava that is later classified as vesicular basalt (Petrich and Eichen, 2010, pp. 30, 41; McMahon et al., 2013, Fig. 3A and 3B). The frazil ice is subsequently underlain by the second, more orderly transition zone due to shielding from surface wind and a more stable substrate of frazil upon which to accrete. This transition layer resembles the entablature, the second layer of a three-part flood basalt. The transition zone is then underlain by the third layer of vertically grained columnar ice, terminating in a delicate skeletal layer - the often 1-3 cm thick leading edge of columnar crystal growth - bathed in a nutrient rich layer of water called the ice-water interface. This interface, whose thickness is influenced by the current speed, can be on the order of a few meters deep, and transitions into the w ater column which often ranges from 20 to over 100 m depth in shelf w aters (Thomas, 2004, pp. 94-96, 115; Petrich and Eicken, 2010, pp. 27-28). The overall topography of the skeletal layer is typically undulating on a scale of roughly one to ten meters, and with sufficient current speed and surface amplitude, zones of relatively high flow? on upstream faces and calmer, sheltered zones on downstream faces may establish themselves. Sympagic amphipods are known to favor the calmer zones, possibly in part due to the reduced energy expenditure to stay in place, and possibly for the increased availability of prey. (Melnikov, 1997, pp.105-108). On the topside, frazil ice may or may not have snowcover, which strongly affects heat exchange, and its presence reduces ice growth rate during freeze-up according to its thickness. Snow also attenuates PAR light (photosynthetically active radiation: 400-700nm wavelength; Lund-Hansen et al., 2020, pp. 71-80), thus its removal my melting or other means can be part of the sequence leading to the onset of ice algae blooms.

[0012] Returning to the flood basalt analog}', as gas inclusions and air bubbles come out of solution and become trapped as they rise to the surface in both solidifying seaw ater and flood basalt, they generate a gradient of pore space that typically varies w ith depth and rate of solidification. The gas bubbles coming out of solution from the cooling molten basalt are aresult of the pressure drop experienced when the pressurized magma is brought to the earth’s surface, whereas the bubbles forming in the ice (not including those which have floated up from the water column) are a result of dissolved gasses in seawater being rejected by the crystallization process. The upper layers of both pack ice and molten flood basalt solidify faster than lower due to the steeper thermal gradient, and thus trap the most gas, so much at times in the case of basalt that the uppermost layer may be classified as scoria, a sponge-like vesicular basalt (Weeks, 2010, p. 223). As with the more slowly cr s tali zed columnar or congelation ice below the transition zone, the slower cooling, lower layer of flood basalt may form into a striking columnar pattern, though on a much larger scale.

[0013] From the perspective of large scale dynamics, pack ice is driven around the Arctic by wind, currents and Coriolis effect (predominantly wind), which set up annually recurring patterns at different scales including the Beaufort Gyre, Transpolar Drift, polynyas (Uspenski’s "Arctic ring of life’; Stirling, 1980) which are loosely analogous to tectonic zones of the earth’s lithosphere driven by convection of the molten asthenosphere. These dynamic pack ice regimes may be broadly classified as:

[0014] 1) Divergent zones - that create leads and polynyas, and notably the open water ‘ice factories’ created by offshore winds along the northern Siberian coast (Melnikov, 1997, pp. 23-24);

[0015] 2) Convergent zones - that create pressure ridges and hummocked ice fields, the most massive along the northeast coast of the Canadian Arctic Archipelago and Greenland. (This MY ice will likely be the last to melt as warming continues). Convergence also includes rafting, which is the pack ice analog of subduction, though the lower ice sheet does not melt to the extent that a subducted plate eventually would as it descends (Weeks, 2010; pp. 330-374);

[0016] 3.) Shear zones - that contribute to stamukhi (grounded rubble sea ice formations at the pack ice and landfast ice interface), and to ridge building within the pack.

[0017] This dynamic landscape of ice can also be said to include a kind of hyper seismicity in which the wind, current and Coriolis effect deform the icescape on the order of fifty million times the drift rate of earth’s current tectonic plates. Accordingly, areas of deformation due to ridging, hummocking, rafting or polynyas may establish themselveswithin only a year, with full maturity of most heavily deformed MY ice patterns requiring up to only a decade or so.

[0018] Regarding strength, the unconfined compressive strength of seasonal winter ice is in the range of 20-30 MPa (Weeks, 2010, p. 257).

[0019] For additional background and context, see Wolf, Max G. “Sea Ice Habitat Restoration Platform, W02024102140A1.BACKGROUND ART

[0020] Current marine vessels with a cantilevering ramp having a leading edge at the bow which is beveled downward below the waterline have claimed to be effective in icebreaking and the creation of ice-free channels. However, such prior art vessels so configured do not deposit extracted pack ice on passing pack to form rafted ice providing an augmented habitat for the aforementioned ice-associated and ice-obligate species; rather, the level sea ice is broken into fragments and pieces and deposited as rubble ice in windrows on passing level sea ice at the edge of ice-free channels.

[0021] For example, U. S. Patent No. 4,436,046 (Braley) discloses an icebreaker that uses its hull at the stem to break up an ice field into pieces and fragments of rubble ice. Ramps are rigidly connected to and substantially surround the hull at the stem. The ramps have sloped surfaces to facilitate the movement of the broken ice fragments out of the water and are contoured to deposit the ice fragments in windrows on the surface of the unbroken ice beneath the outboard extending and downwardly angled sponsons on either side of the hull. Cutting edges with serrated teeth, molded to the ramps and along the hull at the bow, facilitate in breaking a portion of the ice mass into ice fragments. Movable sweep assemblies extending laterally outward from hull sweep the deposited ice fragments (rubble) away from the port and starboard sides of the hull. The ice-breaking boat disclosed in Braley does not raft ice into wide, uniform layers creating or restoring a habitat or ecosystem able to bear the weight of semi-aquatic marine mammals, increase pack ice durability and drift range, increase ice carrying capacity of the other aforementioned species, extend sea-ice derived primary production, enhance the flux of nutrients into the w ater column and eventually to the benthos.

[0022] U. S. Patent No. 857,766 (Stangebye), another example, discloses an ice-breaking boat used to make open lanes through an iced-over harbor for the entry and exit of ships to and from the harbor. The ice-breaking boat has a submerged bow portion. The immediate continuation of the bow above the waterline is formed into an inclined-plane or double inclined plane extending into wings beyond the sides of the boat. The forward portion of the inclined plane or double inclined plane extends downwardly from the superstructure of the ice-breaking boat to the submerged bow portion and is also inclined transversely on opposite sides. The ridge of the inclined plane or double inclined plane is raised at its middle and gradually diminishes toward its juncture with the bow portion at one end and its juncture with the superstructure of the boat at the other end. As the ice-breaking boat is forced ahead by its propulsion system, the ice is lifted from the surface of the water, broken and caused to slide onto the surrounding ice by the inclined plane or double inclined plane and wings, thus claiming to form a clear and unobstructed lane of water as the boat progresses. The ramps of Stangebye terminate with high transverse rafting angles (about 60°), so that the bottom edge of the highly rotated extracted ice often places a high linear load at or near the channel edge, which may result in the extracted ice breaking through and sliding into the channel, or under the ice rather than rafting onto the top. The ice-breaking boat disclosed in Stangebye does not raft ice into wide, uniform layers creating or restoring a habitat or ecosystem able to bear the weight of semi-aquatic marine mammals, or provide the other aforementioned ecosystem benefits; rather, the Stangebye icebreaker treats ice as obstructive, hazardous debris to be eliminated in creating ice free lanes bounded by rubble ice.SUMMARY OF THE INVENTIONTechnical ProblemThe Artic ice cap has been receding at about 13% in area per decade for the past forty years (Garcia-Soto et al.. 2021). Loss of the ice cap was initially estimated by computer modeling to occur by 2100; however, presently, near total loss of the ice cap in the summer is estimated to occur as soon as the 2030s (Wang and Overland, 2009; 2012). Arctic ecosystem populations, such as walrus, pagophilic phocid seals, polar bears, Arctic cod, seabirds, ice algae and others of the aforementioned species which use sea ice as a platform, shelter or substrate will lose increasingly large portions of their habitat for much of the year. Asidefrom geoengineering proposals such as cloud brightening, properly designed ship-mounted rafting devices or moored rafting platforms and methods having the ability to increase sea ice thickness, bearing capacity, durability, surface area, distribution, and the other benefits noted above for the restoration of habitat presently do not exist.Solution to the Problem

[0023] The loss of increasingly large portions of the Artic ice cap and concomitant thinning of pack ice over shelf waters to levels unable to provide habitat for ice-obligate and ice-associated species continues to worsen. We have for the first time exceeded the 1.5 C global average temperature limit over the course of 2023, and staying below a 2 C increase appears doubtful. This continuing decline in ice habitat may be locally mitigated by the construction and deployment of suitably designed icebreaking ships carry ing an ice rafting device including an inclined-plane ice ramp, which in certain embodiments may be one or more of two-sided (double), symmetrical, asymmetrical, cantilevering, or non-cantilevering. Using an icebreaking ship so equipped, strategically placed courses of freeze-bonded rafted ice of two, three, or more layers arranged top to bottom or side to side may be rafted at a rate of up to twenty -five times that of a moored version, for example, at a speed of 2.5 m / s (9 km / hr) with a ship-mounted version vs. 0.1 m / s pack ice drift speed (0.36 km / hr) in a moored version. The basic series of operations for the ship-mounted method includes: 1) Determining that a sufficient number of freezing degree days remains to allow for the freezebonding of newly rafted ice for the designated area; 2) Proceeding to the assigned position for sea ice restoration using the conventional icebreaking bow with the ice rafting device retracted and stowed, which permits the fastest, most fuel efficient sailing; 3) Deployment of the ice rafting device into the water and adjustment of the ship’s ballast for proper ice ramp depth and attitude; 4) Precise alignment of the rafting device’s bow by the ship with the strip of pack ice to be rafted, or alignment parallel to a strip of previously rafted and sufficiently freeze-bonded ice with some selected offset distance to the side; 5) Proceeding forward to raft the level ice, or in the case of previously rafted and freeze-bonded ice to be added to, closely proceeding alongside and depositing the new layer of level ice adjacent to or on top of the previous course while checking for sufficient fit up and submersion depth of the newly rafted ice assembly. One simple pattern to exemplify this step may be a series of antiparalleldisturbance corridors analogous to the furrows created by a farm plow. More complex patterns are easily devised that may build up more massive and durable composite ice formations; 6) When encountering overly large pressure ridges that the ice rafting device cannot break through, retracting it partially or fully as needed, and using conventional icebreaking with the ship’s bow; 7) Retraction and stowage of the rafting device at the end of operations with readjustment of the ship’s ballast to resume conventional sailing.

[0024] The above steps preferably take place during the accumulation of freezing degree days (FDD, which is predominantly winter), and thus may occur in continual darkness according to latitude. For example, there are about sixty-five days of continual darkness at 71° N latitude, aligned with Utqiagvik (formerly Barrow), Alaska, and the north Chukchi Sea, which is one of the proposed areas of deployment. To minimize artificial light disturbance, infrared cameras might be used to monitor ice rafting rather than visible light fixtures.

[0025] The sea ice habitat restoration system in a marine ecosphere proceeding into pack ice under its own power, extracting a pack ice slab from the pack ice using the deployable ice ramp, hogging the extracted sea ice slab by applying a bending moment M to the extracted sea ice slab cracking the extracted sea ice slab under its own weight with a vertex of the ice ramp as the extracted sea ice slab longitudinally traverses the ice-ramp portion at a ramp velocity about equal to the speed of the ship, forming an open water channel in the marine ecosphere aft of the ship, depositing on passing pack ice having a free edge forming a bounding edge of the channel the extracted sea ice slab as rafted pack ice setback from the free edge to form a disturbance corridor of sea ice habitat which may have a terraced ice edge facilitating semi-aquatic marine mammal access to and from the water, or traversal across the disturbance corridor's young ice. The ship-mounted ice rafting device may have similar ramp and rafting wedge geometric and performance characteristics as those described in PCT / US2022 / 49700, and they may also be adapted to more closely conform to and work more effectively with the geometry of an existing icebreaking bow.Ramp Surface Geometry and Deployment Mechanism

[0026] The icebreaking ship may have a design waterline, a beam, a bow, a stem, a longitudinal centerline, a port side, a starboard side, a ship longitudinal axis, Ax, extending from the bow to the stem, a ship transverse axis, Ay, orthogonal to the ship longitudinal axis, Ax, and a vertical axis, Az, orthogonal to the ship longitudinal axis, Ax, and the ship transverse axis, Ay. An inclined-plane ice ramp may be supported by the icebreaking ship.

[0027] The inclined-plane ice ramp may have a linear longitudinal vertex with a positive slope a. The vertex may apply a hogging moment, M, to the extracted pack ice exceeding the flexural strength of of the extracted sea ice as the extracted pack ice longitudinally traverses the forward ice-ramp portion at a ramp velocity about equal to the speed of the ship. The port and starboard ice-ramp portions may have a transverse slope, 8, progressively increasing negatively from a bow of the inebreaking ramp tow ard the stem.

[0028] A forward ice-ramp portion may have a forward ice-ramp portion inlet with a forward ice-ramp portion inlet half-width, R, based on Equation 6 (as stated in ’049700) which is dependent on ice thickness h, ice flexural strength of and ice density pi of the pack ice. The forward ice-ramp portion may have a forward ice-ramp portion shearing zone aft of and contiguous with the forward ice-ramp portion inlet. In the shearing zone, the extracted ice may be lifted above the level pack ice and separated from the level pack ice due to shearing under its own w eight. An aft ice-ramp portion may have port and starboard aft iceramp portion outlet zones aft of and contiguous with the forward ice-ramp portion shearing zone and configured to deposit the extracted sea ice slabs on passing pack ice spaced from the free edge of the pack ice.Ramp Surface Geometry

[0029] In some embodiments, the inclined-plane ice ramp may be a ruled surface bounded by a lower bounding curve and an upper bounding curve. The rulings of the ruled surface may be oriented transverse to the marine ship longitudinal axis. Ax. The lower bounding curve may be formed by the intersection of a horizontally oriented surface and a vertically oriented surface. The upper bounding curve may be formed by an intersection of a frustum of a right circular cone with a sinusoidal surface extruded from a sinusoidal curve.

[0030] A rafting wedge may be supported atop the ice rafting ramp. The rafting wedge may bisect the aft ice-ramp portion into an aft port ice-ramp portion and an aft starboard ice-ramp portion. The aft port ice-ramp portion may extend from a rafting-wedge prow aftwardly along the port side of the ice rafting ramp and be cantilevered outboard from the port side of the ice rafting ramp and / or the icebreaking ship. The aft starboard ice-ramp portion may extend from the rafting-wedge prow aftwardly along the starboard side of the ice rafting ramp and be cantilevered outboard from the starboard side.

[0031] The rafting wedge may have a port rafting wedge wall extending beyond the port side of the rafting ramp and a starboard rafting wedge wall extending beyond the starboard side of the ice rafting ramp. The port and starboard rafting wedge walls may have a rafting wedge wall width, W, which is based on Equation 5 (as stated in ’049700) relating offset distance D for depositing the rafted ice, and ramp inlet width R.

[0032] The bow of the ice rafting ramp may have a leading edge beveled downwardly below the design waterline and have a general shape corresponding to a truncated frustum of an ellipsoid configured to break sea ice having a pressure ridge.

[0033] Regarding deployment, the ice rafting device may be mounted to the ship's forecastle via a hinged mechanism incorporated in the ice rafting device and driven by pinion gear motors and gear train, which is described in the preferred embodiment. This may also provide an example of how an existing icebreaker might be converted to a sea ice habitat restoration ship without significantly degrading its icebreaking and non-icebreaking efficiencies. The ice rafting device deployment mechanism illustrated in the drawings is derived from a four-bar parallel linkage common in machine design, proportioned and arranged to trace out a crescent shaped coupler curve, from the forecastle deck where stowed, to the fully deployed position forward of the bow. The fully deployed ice rafting device is locked in place by two retractable arms on either side of the ship’s bow and a single support at the top of the bow. All three are fitted with hydraulically actuated load-bearing cylinders that act as pin supports allowing local rotation about each pin’s longitudinal axis. There are many other possible methods and locations for mounting an ice rafting device on a vessel.Advantageous Effects of Invention

[0034] The sea ice habitat restoration system and method for extracting and depositing pack ice from pack to form a pack ice disturbance patch and disturbance corridor, inaccordance with the present invention, is based on the principles and corresponding advantageous effects set forth below.

[0035] With the sea ice habitat restoration system in accordance with the present invention, rafting extracted sea ice on level pack ice occurs from above, not from below. To maximize the freeze-bonding rate, the interface between the deposited ice pieces and the top of level ice should be just below sea level in order to maximize exposure to air freezing the water. This is the principle at work in the failed bond-making experiments of Marchenko and Chenot (2009, p. 5; Bailey et al. (2010, p. 13). In one experiment, a 3 x 0.5 * 0.5 m sea ice beam was placed below level ice in the Barents Sea in April 2006. Marchenko and Chenot note that during the experiment the mean air temperature was “-8°C, fluctuating between -11 °C at night to -6°C during the day”. The sea ice beam had still not bonded to the bottom of the level ice after a day. This experiment helps demonstrate a principle that may seem obvious but is easily overlooked: the thermal resistance of the overlying sea ice and seawater retard the extraction of heat by the cold air. This is why thicker level ice grows more slowly than thinner level ice on a strictly thermodynamic basis. Hence using a special hull or other means to raft ice from below rather than from above is not as efficient in freeze-bonding ice for habitat restoration. One example of the rafting-from-below method is the Waas bow for ice breaking (U. S. Patent No. 3,984.091; Tatinclaux, 1988, pp. 23-25).

[0036] With the sea ice habitat restoration system in accordance with the present invention, large, minimally damaged slabs of sea ice are deposited, not rubble ice. This minimal-damage approach favors ramps with (i) gradual slope changes (fair curves), (ii) low rafting angle (maximum transverse angle 5 preferably < 25°). (iii) no steps (with the exception of the ramp outlet termination), (iv) no serrated edges as in Braley, (v) ramp surfaces with low coefficients of friction, (vi) fair wedge wall curvature, and (vii) satisfying an extracted ice segment buckling criterion K (See Appendix A for derivation). To ensure low sloped ramps remain unobstructed, actuated surfaces may be incorporated into ramps and wedge walls in order to clear any rubble or pile-ups.

[0037] With the sea ice habitat restoration system in accordance with the present invention, a preferred vertical step height H minimizes fall height and thus impact load that can damage the ice deposited and the level ice supporting it. To this end. the distance H -from the lower surface of the outer tips of the ice-ramp outlet zones down to the average levelpack ice surface - is preferred to be equal to the average pressure ridge sail height Hsin the area of deployment. In the first preferred embodiment, Hsis for illustrative purposes assumed to be 1.6m, a mean sail height documented for pressure ridges in some parts of the Chukchi Sea (Cammaert and Muggeridge. 1988, p. 25). In this case, if the ship is not deballasted or does not partially retract the ramp, the ramp cantilever portions will collide with and to a variable extent breakthrough or ride over and push down into the w ater that portion of pressure ridges that exceed the mean. This aspect of design must be tailored to the area of deployment and coordinated with the other design requirements. Ballasting and deballasting to avoid all pressure ridges is possible, but may also prove impractical as they can occur at a frequency of 3-10 per km. Since FY ice is now nearly the only ice remaining in the proposed areas of deployment (Arctic shelf waters), large ridges typically found in MY ice should no longer pose a substantial problem (Cammaert and Muggeridge, 1988, p. 25; Shirasawa et al., 2009, Fig. 5, Fig. 6 (a-c)).

[0038] With the sea ice habitat restoration system in accordance with the present invention, extracted sea ice slabs are generally deposited flat on the level pack ice - though doubly rafted (three layers of ice) and canted-rafted (partially doubly rafted, with one end of the top slab supported on level ice and the other on a rafted slab) slabs do occur - with potential benefits detailed further below. To minimize horizontal gap size between rafted ice and level ice and thereby minimize bonding time and the chance of bonding failure, the extracted ice should be deposited flat. This is in contrast to prior art methods of extracting and depositing that needlessly stress the ice, often with resultant fractures and rubble, e.g., as taught by U. S. Patent No. 4,436.046 (Braley) with the resulting rubble ice "windrows'. Depositing rubble on level ice in floodwater (flooding that Braley apparently overlooked) could still produce bonding (like cobbles haphazardly set in a bed of fresh mortar), but with reduced beam-like properties. The overall height of consolidated rubble on level ice will be quite uneven and lower in overall height than rafted slabs on average, assuming the same amount of extracted ice in each case. The moment of inertia and section modulus will also be significantly degraded.

[0039] With the sea ice habitat restoration system in accordance with the present invention, average floodwater immersion depths of approximately h / 2 to h / 7 may be achieved for freeze-bonding at or around a design ice thickness, h. As an example, for a 0.54 m thickcontinuous 4 m wide strip of rafted ice slabs offset from the channel edge about 10 m to the strip centerline, and assuming about 800 kPa flexural strength (hard winter ice), 5.5 GPa elastic modulus and 910 kg / m³ ice density, the average immersion depth from the bottom of the rafted slabs is about 0.16 m, or roughly h / 3. In contrast, 2.15 m thick level ice - near the upper limit still found in the Chukchi - rafted into a strip about 8 m wide and offset from the canal edge about 10 m to its centerline with the same properties, has an average immersion of about 1.1 m, or roughly h / 2. The deeper immersion is due to the wider rafted slabs, assuming breakage sizes according to Equation 6 (as stated in ‘049700. The thicker or stronger the ice. the wider the rafted slabs become; See Description of the Embodiments section of this disclosure). If the 2.15 m rafted strip width is reduced to 4 m for comparison with the 0.54 m ice, with the same 10 m offset, the immersion depth of the rafted strip falls to around 0.3 m, or roughly h / 7. Hence, the greater the thickness and elastic modulus of the level ice, the more widely spread the rafted ice load is over the seawater elastic foundation. Of the basic properties affecting immersion depth of rafted on level ice (ice thickness, strength and elastic modulus), the last two vary with brine volume (brine and gas voids), which in turn depend on ice temperature and salinity. Temperature varies with season and region, and salinity with region, ice age. and amount of brine drainage that has occurred.

[0040] Roughness of the top and bottom ice surfaces will also affect contact area of each surface with the floodwater and therefore influence freeze-bond strength. Immersion depth is also affected by the offset distance D as selected by the designer and is related to Equation 4 (as stated in ‘049700. See Description of the Embodiments section of this disclosure). Finite element analysis with a tensionless Winkler foundation, followed by scale model testing in an ice tank is suggested as one means of refining estimates of immersion depth. Some surface roughness may be desirable to increase freeze-bond contact area, and as a shear key to resist longitudinal shear in the horizontal plane of the ice slabs as generated by flexural loads imposed on the rafted and freeze-bonded slabs.

[0041] The deeper the immersion depth of the rafted slab to level ice interface, the slower the freeze-bond formation since it will be further from the cold air (in winter at times down to -20 to -40 C depending on region) that conducts the heat out and drives freeze-bonding forward, hence creating a decreasing likelihood of bond completion (Marchenko and Chenot, 2009, p. 5; Bailey et al., 2010, p. 13). Freeze-bond formation rate also needs to be consideredin conjunction with the range of pack ice drift velocities (speed and direction) typically observed at the proposed site and along the full length of the projected disturbance corridor, taking into account pack ice convergence and divergence (contraction and expansion of the velocity’ vector field), as these may induce dynamic deformation - ridge building, hummocking, naturally occurring rafting, lead formation, and other discontinuities, which may affect pack ice thickness and the quality of the ship-mounted device’s rafted ice - its uniformity, flatness, fit up, freeze-bond strength and durability. Areas of convergence may need to be avoided or some mitigation measures undertaken if intense enough since sufficiently high compressive forces in the plane of the pack can close the open water channels and corridor.Deployment Site Feasibility Analysis

[0042] While eventually requiring analysis and design by a team of scientists, engineers, contractors, indigenous experts, and other stakeholders, a conceptual framework for evaluating a potential site for rafted ice disturbance corridors is sketched below. This needs to include what are generally considered five basic functions or effects of any ecosystem corridor as described by Forman (1995, pp. 145-153), and further expounded by Hess and Fischer (2001, p. 201, Fig. 1) and others including Hilty et al. (2006, pp.89-115, limited to terrestrial applications), Ray and McCormick-Ray (2014, pp. 183-192, with a focus on various pack ice densities in the MIZ), and Pittman (2017, limited to iceless littoral zones). The five functions or effects are conceptually adapted here to the suggested three-layered matrix concept of seasonally frozen icescape, water column and benthos. Effects generated vary across species, spatiotemporal scales, and of course not all effects can be beneficial for all aspects of the ecosystem at all times. As with most ecological interventions, sufficient data analysis, judgement, debate and consensus must be used to balance the tradeoffs, many of which will only be sufficiently understood with prototyping and then clarified with years of field experience.

[0043] As with the moored platform in ‘049700, the ship-mounted rafting device does have the advantage of creating effects that are local, monitorable and controllable in realtime, and that are readily reversible - as compared to some forms of geoengineering, or compared to various forms of doing nothing. Scaled prototyping in a tank with model icefollowed by in-situ full-scale prototyping will be needed to sufficiently confirm any proposals. The five basic functions or effects to be estimated for a proposed pack ice disturbance corridor are outlined in Table 1 below:Table 1: Five basic functions or effects to be defined for a pack ice disturbance corridor.

[0044] To characterize some preliminary' responses to the above corridor functions or effects, consider a hypothetical offshore site in the Chukchi Sea, midway between Icy Cape, Alaska (a previous mass haulout site for walrus) and Hanna Shoal. The site is in about 43 m of water, limited to 2 m thick level pack ice, and is about 80 km from shore (roughly an 8-hour swim for walrus in open water at atypical speed of around 10 km / hr; Fay, 1982, p. 21) and directly south of Hanna Shoal. The time of year is assumed to be the start of freeze-up, which is now in late November to early December. As noted previously, Hanna Shoal and vicinity’ is a favored foraging area of many Pacific walrus (Jay et al., 2012, pp. 3, 10) since it is a benthic community hotspot, especially regarding bivalves that are key prey for walrus. The rafted sea ice habitat generated along the prospective ice disturbance corridor from a ship-mounted rafting device hypothetically assuming a 30 m beam (B, equal to two ramp widths. 2R) begins with the temporarily open water immediately aft of the ship, which is flanked on each side by newly rafted ice on a depressed, slightly canted pack ice area sloping down tow ards the channel edges w ith resultant flooding. Ice slabs riding up the ramps during extraction and rafting onto level ice may undergo partial brine drainage if the pore space is sufficiently connected, given the reduction of head pressure, which will result in micro-, meio- and some macro fauna and flora being transferred onto the ramps and into the water column predominantly around the ship-mounted rafting device forebody. As the rafted slabs rest partially submerged in flood w ater on the level ice, they may continue to drain, which may transfer more micro-, meio- and macro fauna and flora into the floodw ater along with EPS-laden brine, w hich may invite predation by seabirds, sea ducks and others.

[0045] For the ship-mounted method, it is recommended that disturbance corridor longitudinal axes be aligned with the prevailing drift direction to minimize closure of channels and thus locally maximize new ice production (though it may be the case that closure of a channel may mean the widening of a channel or lead elsewhere, with little or noloss to overall ice production). Pack ice drifting will occasionally reverse direction but typically for only short periods of up to a week. A corridor’s eventually jagged overall curvilinear plan will be formed by all the impinging drift forces accumulated over the course of the ice season. For this hypothetical example at Hanna Shoal, assuming a single shipmounted ice rafting device continually operating from January through May. the total unfolded corridor length is estimated to be over twenty -five thousand kilometers producing over 770 km2(12 Manhattans, 1.3×109m3in volume) of rafted ice, 6.8×108m3of ‘channel’ ice, and 4.7×108m3of flooded ice, with an average ice thickening rate volumetrically equivalent to 1400 pumps continually depositing flooded ice on natural ice assuming 150 m radii and 10 cm / day deposition rate. Rafted ice is ecologically preferable to flooded ice since it favors natural microstructure, macrostructure, hydrology, melting resistance and ecological succession. The rate of production by the ship-mounted device is about twenty -five times that possible with a moored rafting platform, though with tradeoffs that include 1) increased temporary' disturbance to species, particularly ambient noise from the ship as noted in ’049700; 2) a constantly moving open water area aft of the ship rather than a relatively quiet and isolated micro polynya aft of a moored platform (Weeks, 2010, p. 437, Fig. 16.1); 3) use of carbon based fuel (that might be made carbon neutral) or nuclear reactor fuel, as opposed to the wind driven rafting of a platform.

[0046] Given the continuing decline in pack ice habitat, the greatly improved ice production rate of the ship-mounted approach is likely the most efficient and effective for habitat restoration, though a combination of ship-mounted and moored might prove the most robust in averting extinction in some circumstances. By winter’s end, rafted ice from a single pass of the ice rafting device may reach 2.5-4 m (4 m approaching multiy ear status), and a second device lagging the first, preferably with enough time to allow freeze-bonding, may produce 3.7-6 m.

[0047] Depending on the disturbance corridor’s location, some portions of it may still be over shelf water habitat by the end of summer melt, though some may have drifted over the continental slope and deeper water, which will be of little direct use for many of the semi-aquatic species noted as it is beyond some of their favored foraging depths. Nonetheless, there may be benefit to the overall pack ice ecosystem, possibly to micro-, meio- andmacrofauna and flora in and on the ice, and to species not as limited in diving depth or having no need of diving to the benthos.

[0048] The ice disturbance corridor habitat has a pronounced vertical dimension approximated by projecting the outline of the rafted ice and floodwater down to the benthos, and projecting the same outline up to include the atmospheric microclimate, which includes increased ocean-atmosphere exchange of light, heat, vapors and gasses via the open water aft of the ship and its succession of downdrift new ice. This volume approximately encompasses many causal chains of direct and indirect disturbance prior to spring break-up when the rafted ice framework of the corridor begins to disperse into potentially tens of thousands of rafted, freeze-bonded ice floes. Many of the species subpopulations supported by the disturbance corridor will disperse with the rafted ice remnants.

[0049] As an example of indirect disturbance set in motion due to the increased connectivity across and along the disturbance corridor, the resultant increased mobility of semi-aquatic marine mammals, diving seabirds and sea ducks to and from the benthos, enables their bioturbation of benthic sediments as they forage, which resuspends sediments and nutrients that may benefit the benthic community7and in shallow er areas may be entrained as nutrients into higher portions of the water column (Nelson, 1994, pp. 1-24, Fig.4, 5 and 12; Ray and McCormick-Ray, 2014, pp. 129-130).

[0050] Examples of permeability of materials, nutrients and energy transmitted across the corridor include the increased flux of organic carbon (a component of marine snow) from enhanced primary7production through the open water aft of the ship. The disturbance corridor’s permeability also encompasses the increased brine flux into the water column from new ice formation, which increases vertical mixing due to its higher density and hence nutrient flow7. Reduced wind speed and w ind chill, and the resultant accumulation of drifted snow is an example of cross-corridor permeabilities that are less than that of the matrix.

[0051] Leads, which are often precursors of pressure ridges, are typically oriented to ice drift vectors at oblique or nearly perpendicular angles (Wadhams, 2000, p. 152). Hence, pack ice disturbance corridors sufficiently spaced will tend to cut across pressure ridges to produce quadrilateral zones of level ice bounded on tw o sides by depressed row s of rafted ice and on the other two by pressure ridges or leads that may yet form them. From below, the result will be a loose, organic grid of submarine berms from the cracked and canted level ice supportingthe rafted slabs, intersecting with pressure ridge keels. It is suggested that this organic grid may act as a network analogous to hedgerows above and mostly below the waterline, that allows some of the aforementioned aquatic species such as Arctic cod and amphipods to disperse and colonize along them. Such a grid may also impede the spread of oil below pack ice in the event of a spill (Wadhams, 2000, pp. 273-274).

[0052] Along with analyzing a site according to the five basic attributes of a corridor, mapping the succession of pack ice disturbance habitats will help identify which portions of the corridor will be colonized by which species over a particular period. A few examples follow:Adult walrus can break through ice that is up to about 20 cm thick (young ice; Fay, 1982, p.21), but for haulout they need approximately 60 cm (Robards, 2008, p. 19). For the Artic marginal seas where they range, beluga (Delphinapterus leucas). bowhead whales (Balaena mysticetus) and narwhals {Monodon monoceros) may benefit from portions of a disturbance corridor where the ice is thin enough to break through. For a number of weeks after freeze-up begins, they will also be limited to pack that can reach a thickness of around 30 cm which could then be rafted over a number of days into a freeze-bonded composite of about 60 cm to begin supporting their haulout and resting loads. Thus, with the FDD accumulation rate for a site, one can estimate the time at which the ice will reach a 30 cm thickness, so that via the rafted ice they can be provided with minimal natural ice habitat.

[0053] In some contrast to walrus, ice-obligate bearded seals may be able to break through ice with their head up to about 10 cm thick (Cameron et al., 2010, p. 9), but can dive to depths beyond 200 m (Cameron et al., 2010, p. 10), and thus will have a habitat range overlapping with walrus, as they often do in the MIZ, but they may congregate closer to the open water area aft of the ship - or in that direction - in winter due to the 10 cm limit, though with significantly deeper foraging potential. They are benthic feeders like walrus, but epifaunal rather than infaunal in selecting prey (Bums et al., 1985, p.59). Similar estimates can be made for other pagophihc phocids. In general, where the ringed and bearded seals go, the polar bears quickly follow given sufficient ice (Stirling, 1998, pp. 61, 178), and where the bears go, Arctic fox may be close by.

[0054] To generalize, as an animal’s kinetic energy is converted via impact into strain energy of a deflected ice sheet to the point of cracking, the energy to break through is relatedto the square of the speed that the animal can generate prior to impact, its mass, impact angle, and ability to withstand impact. Consequently, more massive, faster animals will be more likely to pioneer thicker new ice, and lighter, slower possibly more fragile species may be limited to thinner ice when on their own, or need to be successors to the pioneers. Thus, the further downdrift of the open water aft of the ship, the more the disturbance corridor may be restricted to animals of higher mass, speed, and resistance to impact injury. One exception in heavier ice will often be ringed seals, which maintain breathing holes by abrasion with their fore flipDetails and Considerations of Rafted Ice Deposition

[0055] With the sea ice habitat restoration system in accordance with the present invention, slabs may be deposited consistently though with some beneficial random variation along the channel edge with gap widths between slabs that will vary with ice thickness as well as the particular design geometry of the ice ramps. For a one-meter ice thickness, gaps may be on the order of two meters or more, which allow the largest marine mammals to circulate to and from level ice to the ice edge in the near field and eventually across newly frozen ice in the far field. Gapping of slabs also induces more snow7drifting, w hich can enhance ringed seal lair-making opportunities (Smith and Stirling, 1975, Fig. 2, 3 and 4). Uniformly placed rafted slabs distribute their weight evenly for less stress on the level ice. While freeze-bonding of rafted and level ice will only proceed with sufficient FDD, there still remains a structural advantage to two or more layers of unbonded ice (i.e., resisting a load in tandem rather than compositely). While no freeze-bond formation with floodwater poses an extreme case, it is also likely that in winter some amount of regelation (localized freezebonding activated by contact pressure) will occur at contact points between slabs since the dead load pressure of the overlying slab will be significant - for example betw een tw o double rafted slabs lying flat against one another and not immersed in freezing w ater. The point at which the remaining FDD for a given year become insufficient for the amount of freezebonding required will vary by region and year.

[0056] With the sea ice habitat restoration system in accordance with the present invention, rafted sea ice is setback from the channel edge in order to create a tiered icescape. This creates steps for a more gradual transition into or out of the water, which may be moreamenable to hauling out and climbing over. This is another aspect that must be tailored to the particular ice habitat restoration required. A larger setback distance will also more widely distribute rafted ice loads. Ice edge load capacity is approximately 2.5 times less than that setback enough to approximate an infinite floating plate (Kerr, 1975, pp. 10-11), and thus poses more risk of rafted ice breaking through the level ice or of sliding back into the channel.SUMMARY OF SELECTED EMBODIMENTS

[0057] In accordance with certain embodiments, a sea ice habitat restoration system is provided for extracting pack ice and depositing the extracted pack ice on passing pack ice to form rafted pack ice through freeze-bonding. The system is configured to be mounted on an icebreaking ship and comprises an ice rafting device including an inclined-plane ice ramp. The ice ramp includes port and starboard portions, with a rafting wedge bisecting the aft portion. The forward ice-ramp portion has an inlet with a half-width determined by a mathematical relationship (stated in ‘049700) based on expected sea ice characteristics. The system applies a hogging moment to the extracted sea ice as it traverses the ramp, and the rafting wedge has walls extending beyond the sides of the ramp with a width determined by another mathematical relationship (stated in ‘049700).

[0058] In any embodiment, the sea ice habitat restoration system may include a linkage in the ice rafting device to support the inclined-plane ice ramp for movement between stowed and working positions. The linkage may comprise forward and aft linkage axles and arms, forming a four-bar linkage with the inclined-plane ice ramp 28 and the icebreaking ship.

[0059] In any embodiment, the sea ice habitat restoration system may include a pair of aft anchors, a center forward anchor and an aft anchor, and locking elements for each to secure the inclined-plane ice ramp to the ship. The forked anchor stay may engage either the forward or aft anchors depending on the position of the inclined-plane ice ramp and may include a load-bearing pin as the locking element.

[0060] In any embodiment, the inclined-plane ice ramp may include a ruled surface bounded by lower and upper bounding curves, with specific geometric configurations and slopes. The lower bounding curve may be formed by intersecting horizontally and verticallyoriented surfaces, while the upper bounding curve may include a frustum of a right circular cone and a sinusoidal surface.

[0061] In any embodiment, the sea ice habitat restoration system may include specific slopes for the vertex and transverse portions of the inclined-plane ice ramp, with the rafting wedge wall width determined by a mathematical relationship (stated in ’ 049700) involving offset distances for cracked and uncracked conditions.

[0062] In any embodiment, the sea ice habitat restoration system may include the rafting wedge having a specific half angle and vertical slope, with walls extending beyond the beam of the ice rafting ramp and having a radius of curvature corresponding to a right circular cone.

[0063] In any embodiment, the sea ice habitat restoration system may include the bow of the ice ramp being beveled and shaped as a truncated frustum of an ellipsoid and thus being configured to break sea ice.

[0064] In accordance with method embodiments, a method for restoring a sea ice habitat is provided, involving navigating a sea ice habitat restoration ship, extracting and hogging pack ice slabs, depositing the slabs as rafted pack ice, and forming a disturbance corridor. A method according to an embodiment of the present invention may include use of the sea ice habitat restoration ship and system as described herein, with specific steps for extracting, hogging, depositing, or forming rafted sea ice.BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The foregoing Summary of the Invention, as well as the follow ing detailed Description of the Embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0066] In the drawings:Fig. l is a port side axonometric view of a preferred embodiment of a sea ice habitat restoration system including an ice rafting device including an inclined-plane ice rampmounted on an icebreaking ship by parallel linkage assembly, all as viewed from below with the ice rafting device partially deployed to show the main components.Fig. 2 is a port side axonometric view of the sea ice habitat restoration system of Fig.1, viewed from above, rafting ice in accordance with the present invention and creating an ice disturbance corridor aft of the sea ice habitat restoration ship;Fig. 3 is a front elevation view of the sea ice habitat restoration system of Fig. 1, with ice habitat not show n for clarity;Fig. 4 is a rear section and elevation view of the sea ice habitat restoration system of Fig. 1, with ice habitat not shown for clarity;Fig. 5 is a plan view of the sea ice habitat restoration system of Fig. 1, with ice habitat not shown for clarity;Fig. 6 is a bottom view of the sea ice habitat restoration system of Fig. 1, with ice habitat not shown for clarity;Fig. 7 is a side elevation view of the sea ice habitat restoration system of Fig. 1 in the stowed position;Fig. 8 is a longitudinal section of the sea ice habitat restoration system of Fig. 1, illustrating the mechanism of deployment, with the inclined-plane ice ramp in the stowed position;Fig. 9 is a front elevation view of the sea ice habitat restoration system of Fig. 1, illustrating the mechanism of deployment,, with the inclined-plane ice ramp in the stowed position;Fig. 10 is a longitudinal section of the sea ice habitat restoration system of Fig. 1. in which the ice rafting device is being deployed with the mechanism rotated about 45 degrees towards the ship’s bow;Fig. 11 is a plan view' of the sea ice habitat restoration system of Fig. 1, in which the inclined-plane ice ramp is in the stowed position;Fig. 12 is a longitudinal section of the sea ice habitat restoration system of Fig. 1. with the ice rafting device fully deployed, with ice habitat not shown for clarity;Fig. 13 is a longitudinal outboard profile of the sea ice habitat restoration system of Fig. 1, with the ice rafting device fully deployed and rafting ice as depicted in Fig. 2;Fig. 14 is a plan view of the sea ice habitat restoration system of Fig. 1, with the ice rafting device fully deployed and rafting ice as depicted in Fig. 2;Fig. 15 is a perspective detail of a center anchor, which attaches the ice rafting device to the bow of the icebreaking ship as depicted in Figs. 2 and 5;Fig. 16 is a perspective detail of a retractable side anchor, which attaches the ice rafting device to the side of bow of the icebreaking ship as depicted in Figs. 4 and 6; and Fig. 17 is a logic flow diagram of a preferred method for restoring a pack ice habitat for semi-aquatic marine mammals and the other aforementioned species in accordance with the present invention;Fig. 18 is an axonometric view of two construction surfaces, whose intersection (heavy dashed) forms the lower bounding curve of the ruled surface of the ramp of Fig. 1, 3, 5 and 6;Fig. 19 is a cross-sectional side elevation view of the two construction surfaces of Fig.18 taken along the lower bounding curve (heavy dashed) of the ruled surface;Fig. 20 is apian view of the two construction surfaces of Fig. 18 intersecting to form the lower bounding curve (heavy dashed) of the ruled surface;Fig. 21 is an axonometric view of a right circular cone and a sinusoidal surface intersecting to form the upper bounding curve (heavy dashed) of the ruled surface of Fig. 1, 3, 5 and 6 at the base of the rafting wedge and along the vertex. Also indicated is wedge wall surface 58 (heavy dashed) as formed by a portion of the frustrum;Fig. 22 is a side view of the frustrum of the right circular cone and the sinusoidal surface of Fig. 21 intersecting to form the upper bounding curve (heavy dashed) of the ruled surface of Fig 1, 3 5 and 6; Below it in side view is the lower bounding curve (heavy dashed);Fig. 23 is a plan view of the frustrum of a right circular cone intersecting with the ramp surface to form a portion of the upper boundary curve (66) of the wedge wall surface (heavy dashed) of the ruled surface of Fig. 1, 3, 5 and 6.DESCRIPTION OF THE EMBODIMENTS

[0067] Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. The terminology used in the description of the invention herein is only for the purpose of describing particular embodiments of the invention and is not intended to be limiting of the invention.

[0068] As used in the description of the invention and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The words "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The words "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0069] The words "right," "left," "lower" and "upper" designate directions in the drawings to which reference is made. The words "inwardly" and "outwardly" refer to directions toward and away from, respectively, the geometric center of the assembly, and designated parts thereof. The terminology includes the words noted above, derivatives thereof and words of similar import.

[0070] As used herein, the word "about" when preceding a numerical value is intended to mean that the disclosed and / or claimed numerical value can be any value within a range of minus 10% to plus 10% of the stated value.

[0071] The following description is directed towards various embodiments of the sea ice habitat restoration system in accordance with the present invention. The preferred area of deployment for the below described embodiments is the Beaufort and Chukchi Seas.

[0072] However, the disclosure is not intended to be exhaustive or to limit the invention to the precise values of the design parameters. Those skilled in the art will appreciate that changes could be made to the embodiments described below for sea ice habitat restoration systems to be deployed in areas other than the Beaufort and Chukchi Seas and having different sea ice properties without departing from the broad inventive concept thereof.FIRST PREFERRED EMBODIMENT

[0073] Referring to the drawings in detail, where like numerals indicate like elements throughout, there is shown in Figs. 1-16 a first preferred embodiment of a sea ice habitat restoration system 150 for extracting pack ice 208 having a thickness h, a characteristic length 1c, and a flexural strength of, and for depositing the extracted sea ice 216 on passing pack ice 210 to form rafted pack ice 226228 230. The sea ice habitat restoration system 150 is configured to be mounted on an icebreaking ship 10, the icebreaking ship 10 having a design waterline 200, a beam 14, a bow 189, a stem 20. a longitudinal centerline 22, a starboard side 24, a port side 26, a ship longitudinal axis, Axextending from the bow 189 to the stem, a ship transverse axis Ay, orthogonal to the ship longitudinal axis Ax, and a ship vertical axis Az, orthogonal to the ship longitudinal axis Axand the ship transverse axis Ay.

[0074] The sea ice habitat restoration system 150 comprises an ice rafting device 11 including an inclined-plane ice ramp 28 supported on the icebreaking ship 10 by a linkage 151. The inclined-plane ice ramp 28 has a forward ice-ramp portion 42 and an aft ice-ramp portion 44.

[0075] A rafting wedge 54 has a rafting-wedge prow 56, with the aft ice-ramp portion 44 extending aftwardly from the rafting- wedge prow 56 and extending in an outboard direction from the sea ice habitat restoration ship (10).

[0076] The forward ice-ramp portion 42 has a forward ice-ramp portion inlet 46, the forward ice-ramp portion 42 having a forward ice-ramp portion inlet half-width, R determined by a mathematical relationship based upon expected sea ice characteristics as:where R is inlet half-width (m);h is sea ice thickness (m);oris sea ice flexural strength (Pa);pi is sea ice density (kg / m3); andg is acceleration of gravity (m / s2).and has a forward-ice-ramp-portion-shearing zone 48, the forward-ice-ramp-portion-shearing zone 48 being aft of and contiguous with the forward ice-ramp portion inlet 46. The aft iceramp portion 44 has an ice-ramp portion outlet zone 50 aft of and contiguous with the forward-ice-ramp-portion-shearing zone 48. The inclined-plane ice ramp 28 has a vertex 62 extending from the forward ice-ramp portion inlet 46 to the rafting- wedge prow 56, the vertex 62 having a positive linear longitudinal vertex slope, a, the vertex configured to apply a hogging moment, M. to the extracted sea ice exceeding the flexural strength, of, of the extracted sea ice as the extracted sea ice longitudinally traverses the forward ice-ramp portion 42. The inclined-plane ice ramp 28 has an ice-ramp portion 30, 32 with a transverse slope, 3, and the transverse slope 8 progressively increases downwardly from a bow 18 of the inclined-plane icebreaking ramp 28 tow ard the stem 20. The rafting w edge 54 has a rafting w edge wall 58, 60 extending beyond a side 24, 26 of the inclined-plane ice ramp 28, the rafting wedge wall 58, 60 have a rafting wedge wall width, W, determined by a mathematical relationship W a; D + R / 2, (Equation 5, as stated in ‘049700) where D is an offset distance for depositing the rafted ice and is a mean of an offset distance Dcr-vmax for a fully cracked condition and an offset distance Dei-vmax for an uncracked, fully elastic condition.

[0077] In certain embodiments, the inclined-plane ice ramp 28 of the sea ice habitat restoration system 150 has a port ice-ramp portion 30 and a starboard ice-ramp portion 32. The port ice-ramp portion 30 has a forward port ice-ramp portion 34 and an aft port ice-ramp portion 36, and the starboard ice-ramp portion 32 has a forward starboard ice-ramp portion 38 and an aft starboard ice-ramp portion 40. The forward port ice-ramp portion 34 and the forward starboard ice-ramp portion 38 form the forward ice-ramp portion 42, and the aft port ice-ramp portion 36 and the aft starboard ice-ramp portion 40 form the aft ice-ramp portion 44.

[0078] In certain embodiments, the rafting wedge 54 bisects the aft ice-ramp portion 44 into the aft port ice-ramp portion 36 and the aft starboard ice-ramp portion 40, the aft port ice-ramp portion 36 extending from the rafting- wedge prow' 56 aftwardly along a port side of the inclined-plane ice ramp 28 and cantilevered outboard from the port side 26 of the sea ice habitat restoration ship 10. the aft starboard ice-ramp portion 40 extending from the raftingwedge prow 56 aftwardly along a starboard side of the inclined-plane ice ramp 28 and cantilevered outboard from the starboard side 26 of the icebreaking ship 10.

[0079] In certain embodiments, each of the port ice-ramp portion 30 and the starboard ice-ramp portion 32 has the transverse slope, 5, and the transverse slope, 5 progressively increases downwardly from the bow 18 of the inclined-plane icebreaking ramp 28 toward the stem 20.

[0080] In certain embodiments, the rafting wedge 54 has a port rafting wedge wall 58 extending beyond the port side 26 of the inclined-plane ice ramp 28 and a starboard rafting wedge wall 60 extending beyond the starboard side 24 of the inclined-plane ice ramp 28. The port and starboard rafting wedge w alls 58 and 60 have the rafting wedge wall width, W, determined by the mathematical relationship:W=D +R2

[0081] where D is the offset distance for depositing the rafted ice and is the mean of the offset distance Dcr-Vmax for a fully cracked condition and the offset distance Dei-vmax for the uncracked, fully elastic condition.

[0082] In some embodiments, including the illustrated embodiment, the inclined-plane ice ramp 28 is symmetrical with respect to the ship longitudinal axis Ax.

[0083] In some embodiments, the inclined-plane ice ramp 28 is cantilevered outboard of a side of the icebreaking ship 10 to deposit ice beyond a bounding edge of a channel 236 formed by the icebreaking ship 10.

[0084] In certain embodiments, the inclined-plane ice ramp 28 is a ruled surface bounded by a lower bounding curve 64 and an upper bounding curve 66 and rulings of the ruled surface are oriented about 90° transverse to a ship longitudinal axis, Ax.

[0085] In some embodiments, the lower bounding curve 64 is formed by an intersection of a horizontally oriented surface 68 and a vertically oriented surface 70. The horizontally oriented surface 68 is extruded from a first curve 72 on the longitudinal axis, Ax, of the icebreaking ship 10, the first curve 72 having a forward portion 74 and an aft-portion 80, the forward portion 74 inclined at a slope 76 of about 10° over a length of about 14.4 m, the aft-portion 80 inclined at a slope of about negative 2° having a length of about 6.8 m via an arc 78 having a radius of curvature of about 30 m and a cord of about 6.3 m, the forward portion 74 transitioning to the aft-portion 80. The vertically oriented surface 70 is extruded from a second curve 82 in a horizontal plane, the second curve 82 having a forward portion 84, a mid-portion 86 and an aft-portion 90. The forward portion 84 is a portion of an ellipse with amajor axis of about 10.83 m and a minor axis of about 5.50 m, the major axis parallel to the mid-portion 86, the forward portion 84 transitioning tangentially at a co-vertex of the ellipse to the mid-portion 86. The mid-portion 86 has a slope of about 30° over a length of about 15.72 m, the mid-portion 86 transitioning to the aft-portion 90 via a portion of an ellipse 88 having a major axis parallel to the mid-portion and about 6.21 m and a minor axis of about 4.24 m. The aft-portion 90 is a line segment having a slope of about 82° from the major axis of the ellipse 88 and having a length of about 3.67 m. The upper bounding curve 66 is formed by an intersection of a frustum 92 of a right circular cone with a sinusoidal surface 94 extruded from the sinusoidal curve. A top 96 of the frustum 92 has a radius of about 25 m with a draft angle 98 of about 21° and is centered about 25 m off the ship longitudinal axis Ax and is offset aft of the icebreaking ship bow 18 about 5.86 m. The sinusoidal surface 94 is extruded along the ship transverse axis Ayfrom a curve 100 having an aft portion 102 defined by a sine wave z = -7cos(2πx / 62) joined at the base of the wedge prow 56 to a forward portion 104 defined by a line coincident with the vertex 62 and having a slope of about 21° tangentially joining the sine wave.

[0086] In some embodiments, the positive linear longitudinal vertex slope is about 21°, and the transverse slope 5 of the port ice-ramp portion 30 and the starboard ice-ramp portion 32 progressively increase from about zero at the bow 18 of the incline-plane ice ramp to about negative 15° toward the stem 20.

[0087] In some embodiments, the rafting wedge wall width W, is determined by a mathematical relationshipW = D + R / 2 (Eqn. 5) and a preferred offset distance D is determined as the mean of the offset distance Dcr-vmax for a fully cracked condition, and the offset distance Dei-vmaxfor an uncracked, fully elastic condition such that:D = 1 / 2 ( D cr-vmax + Del -vmax ), (Eqn. 4) whereDel-vmax = R / 2 + 10 sinh3[ (60- lc) / 120] cos2[n(60-lc) '120]and where a characteristic length 1c in meters is determined by the mathematical relationshipwhere:1c is characteristic length (m);h is mean design ice thickness (m);p is seawater density (kg / m3);g is acceleration of gravity (m / s2);E is ice elastic modulus (Pa);v is Poisson’s ratio, andR is inlet half-width (m).

[0088] The ice rafting device 11 extracts pack ice 208 at about a forward velocity v of the icebreaking ship 10 preferably in a direction aligned with a pack ice prevailing drift direction 214. The pack ice has a nominal thickness h, a characteristic length lc, and a flexural strength or. and deposits the extracted sea ice on passing pack ice 210 to form rafted pack ice 226 with freeze-bonding 234; doubly rafted 228 without freeze-bonding; and canted-rafted 230 with partial freeze-bonding providing an augmented habitat for semi-aquatic marine mammals and the other ice-obligate and ice-associated species. In addition to these rafted ice configurations, the ice rafting device 11, via multiple passes by the icebreaking ship 10 in level ice. forms rafted layers of ice two or more layers thick, as well as layers placed side by side to create arbitrarily wide courses of ice that may interlock analogous to the many patterns found in masonry construction, preferably with sufficient time between rafting for freeze-bonding to occur.

[0089] In certain embodiments, the rafting wedge 54 has a half angle, s, about 25°. and a wedge prow 56, and the port and starboard rafting wedge walls 58, 60 have a negative vertical slope y, less than about 85° and greater than about 75° with respect to an adjacent ramp surface, and an arclength extending beyond the beam 14 of the icebreaking ship 10, and a radius of curvature corresponding to a portion of a right circular cone. In certain embodiments, the bow 18 of the inclined-plane ice ramp 28 has a leading edge 134 beveled downwardly at about 45° at a bow centerline 52 below the design waterline DWL and has a general shape corresponding to a truncated frustum of an ellipsoid having a pressure ridge, the bow 18 being configured to break sea ice.

[0090] In the preferred embodiment, as depicted in the figures herein, the inclined-plane ice ramp 28 is based on the dimensions and geometry stated in ‘049700 (being about 32 mlong x 30 m wide in plan view), and then uniformly stretched to be about 3.2 meters shorter in overall length and about 6.4 m shorter in overall width, resulting in the form thereof being aligned with the proportions of the icebreaking bow 18 shown herein. Whatever preliminary configuration is decided upon, verification with ice tank testing to determine resistance, propulsion, maneuvering, and rafting optimization is required. See Appendix A for additional information on the geometry of the inclined-plane ice ramp 28.

[0091] As in the illustrated embodiment, the ice rafting device 11 may include a linkage 151 configured to support the inclined-plane ice ramp 28 for movement between a stowed position, as shown in Figs. 7-9 and 11, and a working position, as shown in Figs. 2-6 and 12-14, with respect to the icebreaking ship 10, by moving therebetween through an intermediate position, as shown in Figs. 1 and 10. The ice rafting device 11 in the illustrated embodiment comprises: a forward linkage axle 152 configured to be attached to the icebreaking ship 10; an aft linkage axle 156 configured to be attached to the icebreaking ship 10; a forward linkage arm 170 pivotably supported on the forward linkage axle 152 and pivotably engaged with the inclined-plane ice ramp 28; and an aft linkage arm 172 pivotably supported on the aft linkage axle 156 and pivotably engaged with the inclined-plane ice ramp 28. The linkage 151 comprises a four-bar linkage including the forward linkage arm 170, the aft linkage arm 172, the inclined-plane ice ramp 28. and the icebreaking ship 10.

[0092] In any embodiment, the sea ice habitat restoration system 150 may further include a center aft anchor 153 secured to the inclined-plane ice ramp 28; a center forward anchor 157 secured to the inclined-plane ice ramp 28; an anchor stay 158 secured to the icebreaking ship 10; and a locking element 159 configured to engage the anchor stay 158 and at least one of the center aft anchor 153 and the center forward anchor 157 to secure the inclined-plane ice ramp 28 to the icebreaking ship 10. The anchor stay 158, as illustrated, is configured and located to engage the locking element 159 and the center aft anchor 153 when the inclined-plane ice ramp 28 is in the stowed position, and to engage the locking element 159 and the center forward anchor 157 when the inclined-plane ice ramp 28 is in the working position. The anchor stay 158 includes a fork assembly, and locking element 159 includes a loadbearing pin driven by an actuator to engage the fork assembly and a selected one of the center aft anchor 153 and the center forward anchor 157. The four-bar linkage may be anchored to a forecastle 193 of the icebreaking ship 10.

[0093] Any embodiment may include a four-bar linkage 151 anchored to the forecastle 193 of the icebreaking ship.

[0094] Embodiments including a linkage may include a drive motor configured to drive a pinion gear; a drive gear such as an annular drive gear 180 operatively connected to the pinion gear and to a driver spur gear 174, the driver spur gear 174 being operatively connected to rotate the aft linkage arm 172. A gear train assembly 168 may operatively connect the driver spur gear 174 to an idler spur gear 175, the idler spur gear 175 being operatively connected to a follower spur gear 176. The follower spur gear 176 may be operatively connected to rotate the forward linkage arm 170 in a coordinated movement with respect to the aft linkage arm 172.

[0095] The sea ice habitat restoration system 150 may include a retractable side anchor assembly 160 configured to be retractably attached to the icebreaking ship 10 and to extend into a supporting position to support the inclined-plane ice ramp 28 by supporting an aft anchor base 161 of the inclined-plane ice ramp 28. Referring to Fig. 16, a retractable side anchor base hinge 163 may be provided and may be configured to be secured within a recessed housing 164. A retractable side anchor base hinge 163 may be provided and may include a trough receiver 166 configured and located for accommodating a support element in the form of a fixed pin 167 protruding from the aft anchor base 161. The retractable side anchor base hinge 163 may be configured and located to support the inclined-plane ice ramp 28 in the working position by engaging and supporting the fixed pin 167. An actuator 162 may be configured to operatively connect to the retractable side anchor base hinge 163 to retract the retractable side anchor base hinge 163 and to extend the retractable side anchor base hinge 163 into the supporting position.SECOND PREFERRED EMBODIMENT

[0096] Referring to Fig. 17, there is shown a flow diagram for a preferred embodiment of a method for restoring a sea ice habitat for semi-aquatic marine mammals and the other aforementioned species, generally designated 500 and hereafter referred to as the “habitat restoration method, 500 in accordance with the present invention.

[0097] As a first step, the habitat restoration method 500 has a navigating step 510 in which an icebreaking ship 10 proceeds to an assigned position in a marine ecosphere having pack ice. In a preferred embodiment of the habitat restoration method 500, the icebreaking ship 10 that proceeds into the marine ecosphere is any embodiment of a sea ice habitat restoration ship disclosed herein and within the scope of the claims of the present application, including the icebreaking ship 10 described above.

[0098] In an extracting step 512 after the positioning or navigating step 510, a sea ice slab 216 is extracted from the pack ice 208. In a preferred embodiment of the habitat restoration method 500, the pack ice slab 216 is extracted using the inclined-plane ice ramp 28 of the ship-mounted ice rafting device 11.

[0099] In a hogging step 514, a bending moment M is applied to the extracted sea ice slab 216 to crack the sea ice slab 216. In a preferred embodiment of the habitat restoration method 500, the hogging step 514 cracks the extracted sea ice slab under its own weight with the vertex 62 of the inclined-plane ice ramp of the ship-mounted ice rafting device 11 as the extracted pack ice slab longitudinally traverses the forward ice-ramp portion 42.

[0100] In a forming step 513, occurring simultaneously with the extracting step 512, cracking step 514, and deposition step 518, an open-water channel 236 is formed in the marine ecosphere aft of the icebreaking ship 10. The open-water channel 236 is formed by passing pack ice 210 having a free edge 220 forming a bounding edge of the channel. In a preferred embodiment, the open water channel has a port channel free edge 220 spaced from a starboard channel free edge 220 a channel width apart. In some embodiments, the channel width corresponds to the beam 14 of the ice rafting device 11.

[0101] In a depositing step 516, the extracted sea ice slab 216 is deposited as rafted pack ice 226 on passing pack ice 210, set back from the free edge 220 of the pack ice to form a terraced ice edge 229 facilitating semi-aquatic marine mammal haulout and maximizing floodwater 232 volume. In a preferred embodiment of the depositing step 516. the extracted sea ice slab 216 is deposited as rafted pack ice (226 with freeze-bonding 234; doubly rafted 228 without freeze-bonding; and canted-rafted 230 with partial freeze-bonding) on passing pack ice 210, set back from the free edge 220 of the pack ice aft ice-ramp portion outlet zones 50 of the inclined-plane ice ramp 28 of the ice rafting device 11. In the case where one of the focal species for the restoration program includes ringed seals 303 and improved lair-makingopportunities is one of the habitat restoration goals, the included angle y may be set > 90°. If the case where the focal species is walrus, then y may be set to < 85° and greater than about 75°.

[0102] Freeze-bonding 234 of the rafted pack ice on passing pack ice provides a structurally enhanced, tiered icescape amenable to semi-aquatic marine mammal haulout onto the icescape with the passage of sufficient freezing degree days after the deposition of the rafted pack ice. If freeze-bonding 234 does not substantially take place, structural enhancement still occurs, though to a lesser degree than that provided by the composite action of a freeze-bonded assembly. Flooding 232 of the level pack ice 210 due to rafting surcharge loads also provides a method of new ice habitat production (239, 240 and up through FY or MY ice limits for the region) given sufficient freezing degree days (FDD) thereafter.

[0103] The foregoing detailed description of the invention has been disclosed with reference to specific embodiments. However, the disclosure is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Those skilled in the art will appreciate that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. Therefore, the disclosure is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.APPENDIX A. DERIVATION OF ICE SEGMENT BUCKLING CRITERION KIntroduction

[0104] Preliminary ice tank testing by this author demonstrates that the low slope ramps of the first preferred embodiment that produce the least damage to the extracted ice in the rafting process also tend to be more liable to rubble pileups, which may be triggered by buckling of ice segments off of the ramp surfaces. A simple method to quantify ramp curvature with respect to a critical buckling load induced has been found helpful in troubleshooting or assessing if a design is developed enough to be worth the time and cost of a scale model for tank testing.

[0105] To this end a criterion K to estimate onset of ice segment buckling is defined where the upward out-of-plane component Fyof drift force F applied to an ice segment moving over a 2D convex surface is resisted by the sum of frictional forces Fsinduced by upstream ice. As idealized in the free body diagram of Fig. 40 and the accompanying equations below, as the radius of curvature r decreases from infinity - that of a plane, the out-of-plane buckling force Fyincreases to the point where the self-weight of the ice segment (free body 269) no longer resists it and a pair of segments - 268 and 269 - lift off the surface (dashed) rotating about opposing hinge points of ice segments still in contact with inclined-plane ice ramp 28.

[0106] The ratio of characteristic length lcto radius of curvature r measured tangent to the direction of ride-up (for example, along a path 218 for any portion of a ramp in the first preferred embodiment) must be less than a maximum stable ratio established by K such that:where: K is the ice sheet buckling criterion (-);r is radius of curvature (m) aligned with drift force F; jis is coefficient of static friction (-);n (-) is number of ice slab segments upstream of the potential buckling zone resisting sliding;is safety factor (-) against out-of-plane buckling;b (-) is the minimum of A / lcor TC / 4:A is length (m) along ramp vertex from point aligned with strip shearing away from level ice up to prow; and lc is characteristic length (m) as determined by Equation 2 (as stated in ‘049700).Assumptions

[0107] The following assumptions in the free body diagram will tend to hold true for full-scale sea ice and be less true for models in which the scale factor A is greater than 40 (i.e.,very small models relative to full-scale prototypes which are generally avoided by ice tank test facilities; See Tatinclaux, 1988, p. 11):1. Ice flexural rigidity El is sufficiently high such that any bending of ice segments under their own weight to the point that they begin to conform to the convex curve may be neglected.2. Surface tension (Van der Waals forces) between the ice segments and ramp surface are negligible. The higher the scale factor A (the smaller the model), the more surface tension of the liquid phase in which the ice floats may play a role in the segments clinging to the curved surface.3. Loading rate is quasistatic.Maximum Ice Segment Length

[0108] The maximum length L of extracted ice segments (267 to 270) riding up inclined-plane ice ramp 28 is estimated to be the smaller length resulting from two load cases that crack the strip transverse to its direction of ride-up:

[0109] Case 1) Failure of the extracted ice strip with respect to weak axis bending (in combination with torsion, shear, compression, and other loads that will be conservatively assumed as negligible). This weak axis failure length will be assumed equal to that of a floating cantilever ice beam with an upward tip load provided by contact with the ramp (e.g., 42 or further up the ramp in the first preferred embodiment), which is equal to about πlc / 4 (Hetenyi. 1946, p. 24; Daley, 2020, p. 86).

[0110] Case 2) Failure of the strip with respect to strong axis bending due to lateral prying by a prow or wedge wall, which results in a length L of about A - the inclined length of the ramp starting from a point on the vertex aligned with shear points (48 in the first preferred embodiment), up to the base of the prow or wedge wall first contacted. If a strip of extracted ice is not broken in Case 1, the first it will be exposed to as it is lifted from the water, the strip should be broken in flexure against its strong axis as the prow pries it laterally, rotating it about its base near the notch formed at the shear point. Failure may also occur at some other stress riser along its length such as a crack or other discontinuity, but then the segment length L will be less than A. and pose less of a buckling risk. Thus, ice segment maximum length L is defined such that:L = b lc = MIN(A, πlc / 4)where: L is maximum length (m) of a typical ice segment measured along ride-up path of an inclined-plane ice ramp 28 (path 218 in the first preferred embodiment);MIN() is a function that returns the lowest input value; b is a constant (-) as determined below;A is length along the ramp from point of strip shearing away from level ice to prow (m);lc is characteristic length (m) as defined in Equation 2 (as stated in ‘049700);Variable b may also be expressed directly as:b = MIN(A / lc, π / 4)Static Analysis

[0111] For forces in the x-direction, using the xy coordinate plane of Fig. 40. the horizontal component Fx of drift force F is assumed just equal to the resisting force Fs of the ice segments upstream on the ramp. The resisting force is the sum of the products of the coefficient of static friction and the normal force of each segment. These two opposing horizontal components are then:Fx= F cos2φ and Fs= nμsN = nμsρig Ldhwhere:is an angle (radians) from ice segment midpoint to edge n is number of ice slab segments upstream of the potential buckling zone that resist sliding;psis coefficient of static friction (-);p; is sea ice density (kg / m3);g is acceleration of gravity (m / s2);L is ice segment length (m) defined above;d is segment depth (m) normal to section, equal to 1; and h is ice segment thickness (m);The ice segment weight w is used as the normal force N since the portion of the ramp in the diagram on which it bears is level. The normal force for any given curve may be derived to suit a particular condition, though assuming the upstream curve to be level is a conservative, simple estimate suggested for a preliminary calculation.Setting the horizontal drift force Fxequal to the frictional resistance Fsgives:F cos2\| / = npspig LdhFor static equilibrium in the y-direction, vertical force component Fyis assumed just equal and opposite to the tributary self-weight of ice slab 269 that it supports, w / 2, such that:F sin2\p = pig Ldh2where vertical component of drift force Fyand slab weight w are:Fy= F sin2\| / and w = pig LdhTo provide a factor of safety against uplift of slab 269, its weight is divided by Q which has some value greater than 1 as selected by the designer such that:W = pig Ldh2QDividing the x-direction equality by the y-direction equality yields:Pig Ldh / 2psn pig LdhSimplifying yields:tan2q / = l / 2psnQSubstituting l / psn for tan 2 vp into the double-angle identity yields:tan2\| / = 2 tanw(1 - tanfy / )Given that tam| / = L / 2 based on the free body diagram, and substituting L / 2r for tanv| / gives:1 = 2 (L / 2r)2psnQ 1 - (L / 2r)2Cross multiplying:1 -(L / 2r)2= 4psnQ (L / 2r)Rearranging into quadratic form:(L / 2r)2+ (4p.sn ) (L / 2r) - 1 = 0Leting x = L / 2r:x2+ (4psn ) x - 1 = 0Solving for x such that x = (-b ± (b2- 4ac)1 / 2) / 2a:Substituting L / 2r back into the solution for x:Substituting the ice segment length based on characteristic length where L = bkIsolating r and L as a ratio yields:Substituting the definition of characteristic length and introducing scale factor A into all dimensions and elastic modulus to ensure similitude is maintained across scales (Tatinclaux, 1988, p. 5; Note that coefficient of friction is not scaled) yields:Thus, 1 / A at top and bottom cancel indicating similitude is maintained.Setting K equal to the righthand side and requiring that it be greater than the ratio of lc / r ensures buckling resistance with a factor of safety:REFERENCE SIGNS LIST RAFTING DEVICE - SURFACE GEOMETRY AND MOVEMENT 0-199

[0112] 10. Icebreaking ship

[0113] 11. Ice rafting device

[0114] 14. Beam of ice rafting ramp

[0115] 18. Bow of ice rafting ramp

[0116] 20. Stem of ice habitat restoration ship

[0117] 22. Longitudinal centerline

[0118] 24. Starboard side of icebreaking ship

[0119] 26. Port side of icebreaking ship

[0120] 28 Inclined-plane ice ramp

[0121] 29. Forebody of ice rafting ramp

[0122] 30. Port ice-ramp portion

[0123] 32. Starboard ice-ramp portion

[0124] 34. Forward port ice-ramp portion

[0125] 36. Aft port ice-ramp portion

[0126] 38. Forward starboard ice-ramp portion

[0127] 40. Aft starboard ice-ramp portion

[0128] 42. Forward ice-ramp portion

[0129] 44. Aft ice-ramp portion

[0130] 46. Forward ice-ramp portion inlet

[0131] 48. Forward-ice-ramp-portion-shearing zone

[0132] 50. Aft ice-ramp portion outlet zones

[0133] 52. Bow centerline

[0134] 54. Rafting wedge

[0135] 56. Rafting-wedge prow

[0136] 58. Port rafting wedge wall

[0137] 59. Top curve of port rafting wedge wall

[0138] 60. Starboard rafting wedge wall

[0139] 61. Top curve of starboard rafting w edge wall

[0140] 62. Vertex

[0141] 64. Lower bounding curve (or directrix)

[0142] 66. Upper bounding curve (or directrix)

[0143] 68. Horizontally oriented surface

[0144] 70. Vertically oriented surface

[0145] 72. First curve from which horizontally oriented surface is extruded

[0146] 74. Forward portion of first curve

[0147] 76. Slope of forward portion of first curve

[0148] 78. Arc of first curve

[0149] 80. Aft portion of first curve

[0150] 82. Second curve from which vertical oriented surface is extruded

[0151] 84. First portion of second cune

[0152] 86. Mid portion of second curve

[0153] 88. Arc of second curve

[0154] 90. Aft portion of second curve

[0155] 92. Frustum of right circular cone

[0156] 94. Sinusoidal surface

[0157] 96. Top of frustum 92

[0158] 98. Draft angle of frustum 92

[0159] 100. Curve from which sinusoidal surface 94 is extruded

[0160] 101. Base of wedge wall prow joining 102 and 104

[0161] 102. Aft portion of curve 100

[0162] 103. Peak of sine curve 102

[0163] 104. Forward portion of curve 100

[0164] 150. Sea ice habitat restoration system

[0165] 151. Linkage

[0166] 152. Forward linkage axle

[0167] 153. Center aft anchor of ice ramp, for engagement in deployed position

[0168] 155. Forward anchor base of ice rafting ramp

[0169] 156. Aft linkage axle

[0170] 157. Center forward anchor of ice ramp, for stowed position

[0171] 158. Anchor stay: Fork assembly, which secures to the forecastle both fore and aft center anchors of ice ramp for stowed and deployed positions, respectively.

[0172] 159. Center anchor hydraulic load-bearing pin

[0173] 160. Retractable side anchor assembly

[0174] 161. Aft anchor base of ice rafting ramp

[0175] 162. Actuator

[0176] 163. Retractable side anchor base hinge

[0177] 164. Retractable side anchor recessed housing in hull

[0178] 165. Side anchor hydraulic load-bearing pin

[0179] 166. Trough receiver at outer tip of retractable side anchor arm

[0180] 167. Fixed pin protruding from aft anchor base 161

[0181] 168. Gear train assembly

[0182] 170. Forward linkage arm (follower)

[0183] 172. Aft linkage arm (crank)

[0184] 174. Driver spur gear

[0185] 175. Idler spur gear

[0186] 176. Follower spur gear

[0187] 177. Hydraulic load-bearing locking cylinder

[0188] 178. Pinions and motors assembly

[0189] 180. Annular drive gear

[0190] 181. Deck well for annular gear rotation

[0191] 182. Ship’s anchor and recess in bow

[0192] 183. Mounting structure attaching gear trains and axles to forecastle

[0193] 184. Beveled down ramp inlet for pressure ridge breaking

[0194] 186. Filleted edge between pressure ridge breaking surface 134 and forward ice-ramp portion inlet 42

[0195] 188. Bow stem of the icebreaking ship

[0196] 189. Bow of the icebreaking ship

[0197] 190. Ship superstructure

[0198] 191. Ship bridge

[0199] 192. Ship hull

[0200] 193. Ship forecastle

[0201] 194. Ship lights for rafting operations in darknessOCEAN, ICE AND ATMOSPHERE 200-299

[0202] 200. Design waterline (DWL) of rafting device

[0203] 201. Waterline (WL) of floating objects other than the rafting device

[0204] 202. Sea surface

[0205] 204. Water column

[0206] 205. Ice-water interface

[0207] 206. Not used

[0208] 208. Ship moving into pack ice at velocity v

[0209] 210. Pack ice moving by either side of the icebreaking ship 10

[0210] 212. Rubble ice - randomly piled ice slabs from mechanical deformation

[0211] 214. Pack ice relative direction due to ship’s forward motion at velocity v

[0212] 216. Pack ice riding up ramp impelled by ship’s forward motion

[0213] 218. Pack ice ride-up and traversal paths along and off of ramp surfaces

[0214] 220. Free edge of pack ice open water channel created by rafting

[0215] 221. Not used

[0216] 222. Ice flexure crack from hogging moment at ramp vertex 62

[0217] 224. Ice slab sliding off ramp - either driven by pack ice drift force, sliding under gravity, or combination thereof

[0218] 226. Pack ice slab rafted flat onto level ice

[0219] 228. Top ice slab of doubly rafted ice slabs

[0220] 229. Terraced edge formed by rafted ice set back from channel edge

[0221] 230. Canted-rafted ice slab partly supported on flat rafted slab and partly on level ice

[0222] 232. Floodwater due to submersion of level ice under rafted ice strip load

[0223] 234. Frozen floodwater freeze-bonding of rafted slab to level ice

[0224] 235. Pack ice disturbance corridor

[0225] 236. Open water channel

[0226] 237. Ice flexure crack parallel to channel due to rafted ice load on level ice

[0227] 238. Ocean-atmosphere exchange: heat flux and frost smoke MATHEMATICAL SYMBOLS LIST

[0228] a Sea ice melt rate constant (m / °C-days)

[0229] A Maximum extracted ice segment length (m) based on ramp geometry

[0230] Ax Longitudinal axis of ice rafting ramp and ship

[0231] AyTransverse axis of ice rafting ramp

[0232] Az V ertical axis of ice rafting ramp

[0233] b Constant real number (-)

[0234] B Beam of ice rafting ramp (m)

[0235] d Depth of ice segment (m), normal to section plane

[0236] g Acceleration of gravity (m / s2)

[0237] h Nominal level pack ice thickness (m)

[0238] hf Final sea ice thickness (m) after melting

[0239] hi Initial ice thickness (m) prior to melting

[0240] hpcti Ice thickness (m) of a specified percentile rank

[0241] H Height (m) from design waterline to bottom of cantilever ramp tip

[0242] HsMean height (m) of pack ice pressure ridge for area of deployment

[0243] lc Level sea ice characteristic length (m)

[0244] L Length (m) of idealized ice slab segment riding up or rafting from ramp

[0245] M Hogging moment (kN-m)

[0246] N Normal force (kN)

[0247] r Radius of curvature (m)

[0248] R Forward ice-ramp portion inlet half-width (m)

[0249] S Maximum ramp cantilever tip distance (m) from rafting device centerline

[0250] T Draft of ice rafting ramp (m)

[0251] U Height (m) of rafting wedge wall

[0252] v Component of ship speed (m / s) relative to ice pack

[0253] w Ice slab self-weight (kN)

[0254] W Rafting wedge wall width (m)

[0255] a Slope of incline-plane ice ramp vertex (deg) with respect to horizontal

[0256] (3 Slope of pressure ridge breaking surface at bow centerline (deg)

[0257] y Included angle between wedge wall and adjacent ramp surface (deg)

[0258] 5 Transverse slope of port and starboard ice-ramp portions (deg)

[0259] e Rafting wedge prow half angle (deg) in plan view

[0260] r| Fillet radius of curvature (m) at beveled down edge at bow centerline

[0261] K Ice segment buckling criterion (-)

[0262] A Scale factor of model to full-scale prototype (-)

[0263] A Wavelength (m)

[0264] (j, Mean design level pack ice thickness (m), not including ridges

[0265] ,sCoefficient of static friction (-)

[0266] v Poisson’s ratio (-)

[0267] 9 Right circular cone draft angle (deg)

[0268] p Seawater density (kg / m3)

[0269] pi Sea ice density (kg / m3)

[0270] o Standard deviation (same dimensions as mean)

[0271] a Sea ice flexural strength (Pa)

[0272] 4> Bow stem angle (deg)

[0273] v| / Angle (radians) between centerline and edge of ice segment of length L on 2D ramp with radius of curvature r

[0274] Safety factor (-)ABBREVIATIONS LIST

[0275] CL Centerline

[0276] DWL Design w aterline of rafting device

[0277] FY First year (ice)

[0278] MIZ Marginal ice zone

[0279] MY Multiyear (ice)

[0280] WL Waterline of floating objects other than the rafting deviceCITATIONS LISTPatent Literature

[0281] Braley, W. (1984), Ice-Breaking Hull, U. S. Patent No. 4,436,046.

[0282] Stangebye, C. (1907), Boat for Ice Breaking and Other Purposes, U. S. Patent No.857,766.

[0283] Waas, H. (1976), Icebreaker Vessel, U. S. Patent 3,985,091.Non-Patent Literature

[0284] Al-Harthi, A. A., Al-Amri, R. M., & Shehata, W. M. The porosity and engineering properties of vesicular basalt in Saudi Arabia. Engineering Geology, Vol. 54. no. 3-4, (Oct. 1, 1999), pp. 313-320.

[0285] Alonso-Gonzalez, I. J., Aristegui, J., Lee, C., Sanchez-Vidal, A., Calafat, A., Fabres, J.,... & Benitez-Barrios, V. Role of slowly settling particles in the ocean carbon cycle. Geophysical Research Letters, Vol. 37, no. 13, (Jul. 15, 2010).

[0286] Anderson, D. L. Growth rate of sea ice. Journal of Glaciology, Vol. 3, no. 30, (1961), pp. 1170-1172.

[0287] Arias, P., Bellouin, N., Coppola, E., Jones, R., Krinner, G., Marotzke, J.,... & Zickfeld, K. Climate Change 2021: The Physical Science Basis. Contribution of Working Groupl4 I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change; Technical Summary, (2021).

[0288] Arrigo, K. R., Mock, T., & Lizotte, M. P. ‘'Primary Producers and Sea Ice." in: Thomas, D. N. and Dieckmann, G. S., Sea Ice, 2ndEd., (Wiley-Blackwell, 2010), pp. 283-325.

[0289] Arrigo, K. R. The changing Arctic Ocean. Elementa: Science of the Anthropocene, 1. (Jan. 1, 2013). https: / / online.ucpress.edu / elementa / article / doi / 10.12952 / joumal.elementa.000010 / 112329 / Th e-changing-Arctic-OceanThe-changing- Arctic-Ocean

[0290] Bailey, E., Feltham, D. L., and Sammonds, P. R. A model for the consolidation of rafted sea ice. Journal of Geophysical Research: Oceans, Vol. 115, No. C4, (Apr. 9, 2010). https: / / agupubs.onlinelibrary.wiley.eom / doi / 10.1029 / 2008JC005103

[0291] Baveye, P., Vandevivere, P., Hoyle, B. L., DeLeo, P. C., and Sanchez de Lozada, D._ Environmental Impact and Mechanisms of the Biological Clogging of Saturated Soils and Aquifer Materials, Critical Reviews in Environmental Science and Technology, Vol. 28, no. 2 (1998), pp. 123-191. DOI: 10.1080 / 10643389891254197

[0292] Belikov, S„ Boltunov, A., and Gorbunov, Y. DISTRIBUTION AND MIGRATION OF POLAR BEARS. PACIFIC WALRUSES AND GRAY WHALES DEPENDING ON ICE CONDITIONS IN THE RUSSIAN ARCTIC, 17th Symposium on Polar Biology, (1996), pp. 263-274.

[0293] Berge, J., Geoffrey, M., Daase, M., Cottier, F., Priou, P., Cohen, J. H.,... & Gauthier. S. (2020). Artificial light during the polar night disrupts Arctic fish and zooplankton behaviour down to 200 m depth. Communications Biology. 3(1), 102.

[0294] Bilello, M. A. Maximum thickness and subsequent decay of lake, river, and fast sea ice in Canada and Alaska, US Army, Corps of Engineers, Cold Regions Research and Engineering Laboratory, Vol. 80, no. 6 (Feb. 1980), pp. 29-34.

[0295] Bluhm. B. A.. Gradinger. R. R.. and Schnack-Schiel, S. B. “Sea Ice Meio- and Macrofauna.” in: Thomas, D. N. and Dieckmann, G. S., Sea Ice, 2nd Ed. (Wiley-Blackwell, 2010), pp. 357-394.

[0296] Brown, T. G. Confederation Bridge - An innovative approach to ice forces, in: Proceedings of the Annual Conference of the Transportation Association of Canada, Prince Edward Island (2006).https: / / citeseerx.ist.psu. edu / viewdoc / download?doi=10.1.1.1053.9873&rep=repl&type=pdf

[0297] Brown. T. A., Alexander, C., Yurkowski, D. J., Ferguson, S. H., & Belt, S. T. Identifying variable sea ice carbon contributions to the Arctic ecosystem: A case study using highly branched isoprenoid lipid biomarkers in Cumberland Sound ringed seals. Limnology and Oceanography, Vol. 59, no. 5 (2014), pp. 1581-1589.https: / / aslopubs.onlinelibrary.vviley.eom / doi / pdf / 10.4319 / lo.2014.59.5.1581

[0298] Brown, T. A., Galicia, M. P., Thiemann, G. W., Belt, S. T., Yurkowski, D. J., & Dyck, M. G. High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue. PloSone, Vol. 13, no. 1 (Jan. 23, 2018). e0191631. https: / / joumals.plos.org / plosone / article7idM0.1371 / journal.pone.0191631

[0299] Dyer. Ira. "Speculations on the origin of low frequency Arctic Ocean noise." in: Kerman, B. R., Sea Surface Sound (Dordrecht, Kluwer Academic Publishers, 1988), pp. 513-532.

[0300] Burns, J. J.. Frost, K.. J., Lowry, L. F. (Eds.), Idarine Idammals Species Accounts. Alaska Department of Fish and Game, Division of Game, Mar. 1985.

[0301] Cammaert, A., and Muggeridge, D. B. Ice Interaction with Offshore Structures. New York, Van Nostrand Reinhold, 1988.

[0302] Cameron, M. F., Bengtson, J. L., Boveng, P. L., Jansen, J. K., Kelly, B. P., Dahle, S. P.,... & Wilder, J. M. Status review of the bearded seal (Erignathus barbatus), U. S.Department of Commerce. NOAA Technical Memorandum NMFS-AFSC-211 (Dec. 2010). https: / / www.researchgate.net / profile / Brendan-Kelly- 6 / publication / 270571869_Status_review_of_the_bearded_seal_Erignathus_barbatus / links / 56 abd42708ael9a385115764 / Status-review-of-the-bearded-seal-Erignathus-barbatus.pdf

[0303] Chen. J., Blume, H. P. & Beyer. L. Weathering of rocks induced by lichen colonization - a review. Catena, Vol. 39, no. 2, (Mar. 1, 2000), pp. 121-146.

[0304] Conlan, K. E., Lenihan, H. S., Kvitek, R. G., & Oliver, J. S. Ice scour disturbance to benthic communities in the Canadian High Arctic. Marine Ecology’ Progress Series, Vol.166, (May 28, 1998), pp. 1-16.

[0305] Daley, C. Sea Ice Engineering: theory and application. Lecture note for EN8674 / 9096. Memorial University' of Newfoundland, 2020.https: / / www. engr. mun. ca / ~cdaley / 8074 / IceT extv 1 Oj. pdf

[0306] Dieckmann, G. S., and Hellmer, H. H. “The Importance of Sea Ice: An Overview.’7in: Thomas. D. N. and Dieckmann, G. S., Sea Ice. 2ndEd., (Wiley-Blackwell. 2010), pp.1-22.

[0307] Den Boer, P. J. Spreading of risk and stabilization of animal numbers. Acta biotheoretica, Vol. 18, no. 1 (Mar. 1968), pp. 165-194.

[0308] Eisendle-Flockner, U. and Hilberg, S. Hard rock aquifers and free-living nematodes-an interdisciplinary approach based on two widely neglected components in groundwater research. Ecohydrology, Vol. 8, no. 3 (Apr. 2015), pp. 368-377.

[0309] Fay, F. H. ‘“The role of ice in the ecology of marine mammals of the Bering Sea.” in: Hood, D. W. and Kelley, E. K._ Oceanography of the Bering Sea (Institute of Marine Science, Univ. Alaska, Fairbanks, 1974). pp. 383-399.

[0310] Fay, F. H. Ecology and biology of the Pacific walrus, Odobenus rosmarus divergens liliger. U. S. Department of the Interior, Fish and Wildlife Service, American Fauna. No. 74 (1982), pp. 1-279.

[0311] Ferguson, S. H., Stirling, I., and McLoughlin, P. Climate change and ringed seal Phoca hispida) recruitment in western Hudson Bay Marine Mammal Science. Vol. 21, no. 1 (Jan. 2005) pp. 121-135.

[0312] Fischbach, A. S., Monson, D. H., and Jay, C. V. Enumeration of Pacific walrus carcasses on beaches of the Chukchi Sea in Alaska following a mortality event, September 2009. U. S. Department of the Interior, U. S. Geological Survey, Open-File Report 2009-1291. (2009). https: / / pubs.usgs.gov / of / 2009 / 1291 / pdf / ofr20091291.pdf

[0313] Forman, R. T. T., and Godron, M. Landscape Ecology. New York, Wiley & Sons, 1986.

[0314] Forman, R. T. T., Land Mosaics: The ecology of landscapes and regions.Cambridge, Cambridge University Press, 1995.

[0315] Francis, O., Metzger, A. T., Statscewich, H. & Winsor, P. Physical Oceanographic and Meteorological Data for the Beaufort and Chukchi Seas to Support Reliability -Based Design Criteria for Arctic Offshore Oil and Gas Structures. US Dept, of the Interior, Bureau of Safety and Environmental Enforcement (BSEE). BSEE contract number: E13PC00014. (Feb. 2016). https: / / catalog.northslopescience.org / dataset / 2492 / resource / 23b64223-e73c-4f72-8afe-f31adl03013c

[0316] Garcia-Soto, C., Cheng, L., Caesar, L.. Schmidtko, S.. Jewett. E. B., Cheripka, A.,... & Abraham, J. P. An Ovendew of Ocean Climate Change Indicators: Sea Surface Temperature, Ocean Heat Content, Ocean pH, Dissolved Oxygen Concentration, Arctic Sea Ice Extent, Thickness and Volume, Sea Level and Strength of the AMOC (Atlantic Meridional Overturning Circulation). Frontiers in Marine Science. (Sep. 21, 2021).htps: / / www.proquest.com / openview / lf69010a5ee5eb0a9a25ae7f5b26c5f8 / 17pq-origsite=gscholar&cbl=2049538

[0317] Golden, K. M., Mathematics of Sea Ice. The Princeton companion to applied mathematics. Princeton: Princeton University Press. 2014.

[0318] Grebmeier. J. M.. L. W. Cooper. H. M. Feder, and B. I. Sirenko. Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic. Progress in Oceanography, Vol. 71 (2006), pp. 331-361.

[0319] Grebmeier, J. M., and Barry, J. P. “Benthic Processes in Polynyas.’' in: Smith, W. O. Jr and Barber, D. G., Polynyas: Windows to the World, Elsevier oceanography series 74. (Amsterdam, Elsevier, 2007), pp. 363-390.

[0320] Grebmeier, J. M., Bluhm, B. A., Cooper, L. W., Danielson, S. L., Arrigo, K. R., Blanchard, A. L.,... & Okkonen, S. R. Ecosystem characteristics and processes facilitating persistent macrobenthic biomass hotspots and associated benthivory in the Pacific Arctic. Progress in Oceanography, Vol. 136 (2015), pp. 92-114.

[0321] Hahn H. J. and Matzke D A. Comparison of stygofauna communities inside and outside groundwater bores. Limnologica, Vol. 2, no. 35(1-2), (May, 2005), pp. 31-44.

[0322] Hancock, P. J., Boulton A. J., and Humphreys W. F. Aquifers and hyporheic zones: towards an ecological understanding of groundwater. Hydrogeology Journal. Vol. 13, no. 1, (Mar. 2005), pp. 98-111.

[0323] Harper, J. L., Population Biology of Plants. London, Academic Press, 1977.

[0324] Hess G. R., and Fischer R. A. Communicating clearly about conservation corridors. Landscape and Urban Planning. Vol. 55, no. 3 (Jul 30, 2001), pp. 195-208.

[0325] Hetenyi, M. Beams on Elastic Foundation: Theory with applications in the fields of civil and mechanical engineering. Ann Arbor, University of Michigan Press, 1946.

[0326] Hibler W. D. “Arctic Ice-Ocean Dynamics.” in: Herman, Y., The Arctic Seas. (New York, Van Nostrand Reinhold, 1989), pp. 47-91.

[0327] Hilly. J. A.. Lidicker Jr, W. Z.. and Merenlender, A. M. Corridor Ecology: The Science and Practice of Linking Landscapes for Biodiversity Conservation. Washington, Island Press, 2006.

[0328] Homer, R. A. "Arctic Sea-ice Biota." in: Herman, Y., The Arctic Seas. (New York, Van Nostrand Reinhold. 1989), pp. 123-146.

[0329] ISO 19906, 1. S. O. Petroleum and Natural Gas Industries- -Arctic Offshore Structures. 2ndEd. Geneva, ISO, Sep. 2019. Reference number ISO 19906:2019(E)

[0330] Ivanova, S. V., Kessel, S. T., Espinoza, M., McLean, M. F., O'Neill, C., Landry, J.,... & Fisk, A. T. Shipping alters the movement and behavior of Arctic cod (Boreogadus saida). a keystone fish in Arctic marine ecosystems. Ecological Applications, (2020). Vol. 30, no. 3, e02050.

[0331] Jay, C. V., Farley, S. D., and Gamer, G. W. Summer diving behavior of male walruses in Bristol Bay, Alaska. Marine Mammal Science, Vol. 17, no. 3 (Aug. 26, 2006), pp.617-631.

[0332] Jay, C. V., Fischbach, A. S. and A. A. Kochnev. Walrus areas of use in the Chukchi Sea during sparse sea ice cover. Marine Ecology Progress Series (Nov. 14, 2012) Vol. 468, pp. 1-13. doi: 10.3354 / mepsl0057.https: / / www.int-res.com / articles / feature / m468p001.pdf

[0333] Jizu, X., S. Qingzeng, S. An, F. Yunlin, and L. Tongkui. Sea Ice Engineering in China, Journal of Coastal Research, Vol. 7, no. 3 (Summer 1991), pp. 759-770.

[0334] Johnston, C. A., & Naiman, R. J. Boundary7dynamics at the aquatic-terrestrial interface: the influence of beaver and geomorphology. Landscape Ecology. Vol. 1, no. 1 (1987). pp. 47-57.

[0335] Kamovsky, N. J., and Gavrilo, M. V. “A feathered perspective: the influence of sea ice on Arctic marine birds.” in: Thomas, D. N., Sea Ice, 3rdEd. (Chichester UK, Wiley-Blackwell, 2017), pp. 555-569.

[0336] Keighley. X.. Olsen, M. T., Jordan, P.. & Desjardins, S. P. (Eds.). The Atlantic Walrus: Multidisciplinary Insights into Human-Animal Interactions. London, Academic Press, 2021.

[0337] Kelly B. P. and Wartzok D. Ringed seal diving behavior in the breeding season. Canadian Journal of Zoology, Vol. 74, no. 8 (Aug. 1, 1996), pp.1547-1555.

[0338] Kerr, A. D. The bearing capacity of floating ice plates subjected to static or quasistatic loads: a critical survey. Vol. 333 (Corps of Engineers, US Army, CRREL, 1975).

[0339] Kohlbach, D., Schaafsma, F. L., Graeve, M., Lebreton, B., Lange, B. A., David, C.,... & Flores, H. Strong linkage of polar cod (Boreogadus saida) to sea ice algae-producedcarbon: evidence from stomach content, fatty acid and stable isotope analyses. Progress in Oceanography, Vol. 152 (Mar. 2017), pp. 62-74.

[0340] Krembs, C., Eicken, H., and Deming, J. W. Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic. Proceedings of the National Academy of Sciences. Vol. 108, no. 9 (Mar. 1, 2011), pp.3653-3658.

[0341] Leontowich. K. A study of the benthic faunal distribution in the subtidal zone of Turton Bay, Igloolik Island, Nunavut. Faculty of Graduate Studies and Research. University of Regina. (2004).https: / / ourspace. uregina. ca / bitstream / handle / 10294 / 13127ZMQ92856.pdf?sequence= 1

[0342] Lonne, O. J. “On Productivity in Ice-Covered Polar Oceans.” in: Wettlaufer, J. S., Dash, J. G., and Untersteiner. N., Ice Physics and the Natural Environment (Berlin, Springer, 1999), pp. 209-218.

[0343] Lund-Hansen, L. C., Sogaard, D. H., Sorrell, B. K., Gradinger, R., and Meiners, K. M. Arctic Sea Ice Ecology. Cham, Switzerland, Springer International Publishing, 2020.

[0344] Markus, T., Stroeve, J. C., and J. Miller. Recent changes in Arctic sea ice melt onset, freezeup, and melt season length, Journal of Geophysical Research: Oceans, Vol. 114, no. Cl 2024 (Dec., 2009).https: / / agupubs. onlinelibrary, wiley. com / doi / pdf / 10.1029 / 2009JC005436

[0345] Marchenko A and Chenot C., Regelation of ice blocks in the water and on the air, Proceedings of the 20th International conference on Port and Ocean Engineering under Arctic Conditions (POAC). Lulea, Sweden, June 9-12, 2009.

[0346] McLaren, I. A. The biolog: of the ringed seal (Phoca hispida Schreber) in the eastern Canadian Arctic. Vol. 118. Ottawa (Canada), Fisheries Research Board of Canada, 1958.

[0347] McMahon S.. Parnell J., Ponicka J, Hole M., and Boyce A. The habitability’ of vesicles in martian basalt. Astronomy & Geophysics. (Feb. 2013) Vol. 54, no. 1. pp.1-7. https: / / doi.org / 10.1093 / astrogeo / ats035

[0348] Mellor, M. “Mechanical Behavior of Sea Ice.” in: The Geophysics of Sea Ice. (New York, Plenum, 1986), pp. 165-281.

[0349] Melnikov, I. A. The Arctic Sea Ice Ecosystem. Amsterdam, Gordon and Breach.1997.

[0350] Moore, S. E., and Huntington, H. P. Arctic Marine Mammals and Climate Change: Impacts and Resilience. Ecological Applications. (Mar. 2008). Vol. 18, no. sp2. pp. S157-S165.

[0351] Mundy, C. J. and Meiners, K. M., “Ecology of Arctic Sea Ice.” in: Thomas, D. N., Ed. Arctic Ecology7. Hoboken, N. J., John Wiley -Blackwell, 2021.

[0352] Nelson, C. H. Gray whale and Pacific walrus benthic feeding grounds and sea floor interaction in the Chukchi Sea. Menlo Park, California, US Department of the Interior. Minerals Management Service, Alaska Outer Continental Shelf Region, 1994.

[0353] Peacock, E., Derocher, A. E., Lunn, N. J., and Obbard, M. E. “Polar Bear Ecology and Management in Hudson Bay in the Face of Climate Change.” in: Ferguson, S. H. et al., A Little Less Arctic. (Dordrecht. Springer. 2010), pp. 93-116.

[0354] Perovich, D. K., Richter-Menge, J. A., Jones, K. F., and Light, B. (2008).Sunlight, water, and ice: Extreme Arctic sea ice melt during the summer of 2007.Geophysical Research Letters, Vol. 35, no. 11 (Jun. 3, 2008).

[0355] Perovich et al. Arctic report card: Update for 2019: Arctic ecosystems and communities are increasingly at risk due to continued warming and declining sea ice. NOAA. https: / / arctic.noaa.gov / Report-Card / Report-Card-2019 / ArtMID / 7916 / ArticleID / 841 / Sea-Ice

[0356] Petrich, C., and Eicken, H. “Growth, Structure and Properties.” in: Thomas, D. N. and Dieckmann, G. S., Sea Ice, 2ndEd. (Wiley-Blackwell, 2010), pp. 23-78.

[0357] Pittman, S. J. (Ed.). Seascape Ecology. Hoboken, NJ, John Wiley & Sons, 2017.

[0358] Pounder, E. R. The Physics of Ice. Oxford, Pergamon Press, 1965.

[0359] Sousa, W. P. “Disturbance and Patch Dynamics on Rocky Intertidal Shores.” in: Pickett, S. T. A. and White, P. S. The Ecology of Natural Disturbance and Patch Dynamics. (Orlando, Florida, Academic Press, 1985).

[0360] Pritchard. R. S. and Thomas. D. R. 1985. Chukchi Sea Ice Motions 1981-82. Flow Industries Inc., Research and Technology Division, Mar. 1985.

[0361] Ray, G. C., and McCormick-Ray, J. Marine Conservation: Science, Policy, and Management. Malaysia, Wiley Blackwell, 2014.

[0362] Robards, M. D. Perspectives on the Dynamic Human-Walrus Relationship.: A Dissertation for the Degree of Doctor of Philosophy. Fairbanks, University of Alaska, 2008.

[0363] Rosen, Y. Chukchi Sea walruses are massing on shore earlier than ever. Arctic Today Business Journal. August 5, 2019.https: / / www.arctictoday.com / chukchi-sea-walruses-are-massing-on-shore-earlier-than-ever /

[0364] Saar, M. O., and Manga, M. Permeability -porosity relationship in vesicular basalts. Geophysical Research Letters, Vol. 26, no.l (Jan. 1, 1999), pp. 111-114.

[0365] Schwarz, J. and Weeks, Wilford. Engineering Properties of Sea Ice. Journal of Glaciology, Vol. 19. no. 81 (1977), pp. 499-531.

[0366] Shirasawa, K., Eicken, H., Tateyama, K., Takatsuka, T., & Kawamura, T. Sea-ice-thickness variability in the Chukchi Sea, spring and summer 2002-2004. Deep Sea Research Part IP. Topical Studies in Oceanography, Vol. 56, no. 17 (Aug. 1, 2009), pp. 1182-1200.

[0367] Smith, T. G., and Stirling, I. The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures. Canadian Journal of Zoology, Vol. 53. no. 9 (Sep. 1, 1975), pp. 1297-1305.

[0368] Solomon, S., Plattner, G. K., Knutti, R., & Friedlingstein, P. (2009). Irreversible climate change due to carbon dioxide emissions. Proceedings of the national academy of sciences. (Feb. 10, 2009) Vol. 106, no. 6, pp. 1704-1709.

[0369] Sousa, W. P. ‘'Disturbance and Patch Dynamics on Rocky Intertidal Shores.” in: Pickett, S. T. A. and White, P. S. The Ecology of Natural Disturbance and Patch Dynamics. (Orlando, Florida, Academic Press, 1985).

[0370] Stirling I. The biological importance of polynyas in the Canadian Arctic. Arctic, (Jun. 1, 1980), Vol. 303, no. 15.

[0371] Stirling, I. Polar Bears. Ann Arbor, University of Michigan Press, 1998.

[0372] Stirling, I., and Smith, T. G. Implications of warm temperatures and an unusual rain event for the survival of ringed seals on the coast of southeastern Baffin Island. Arctic, (Mar. 2004). pp. 59-67.

[0373] Stroeve, J. C., Markus, T., Boisvert, L., Miller, J., & Barrett, A. (2014). Changes in Arctic melt season and implications for sea ice loss. Geophysical Research Letters, Vol.41, no. 4. (Feb. 22, 2014), pp. 1216-1225.https: / / agupubs.onlinelibrary.wiley.com / doi / pdfdirect / 10.1002 / 2013GL058951

[0374] Stroeve, J. C., Schroder, D., Tsamados, M., & Feltham, D. Warm winter, thin ice?. The Cryosphere. Vol. 12, no. 5 (May 30, 2018), pp. 1791-1809.

[0375] Tatinclaux, J. C. Model tests in ice of a Canadian Coast Guard R-class icebreaker. Special Report 84-6. U. S. Hanover, New Hampshire, Army Corps of Engineers (Apr. 1984). https: / / erdc-library.erdc.dren.mi1 / jspui / bitstream / l 1681 / 11869 / l / SR-84-6.pdf

[0376] Tatinclaux, J. C. Ship model testing in level ice: An overview. Report 88-15, U. S. Hanover, New Hampshire, Army Corps of Engineers (Oct. 1988).https: / / erdc-library.erdc.dren.mi1 / jspui / bitstream / 11681 / 9073 / l / CRREL-88-15.pdf.

[0377] Tchesunov. A. V., and Riemann. F. Arctic sea ice nematodes (Monhysteroidea), wi th descriptions of Cryonema crassum gen. n., sp. n. and C. tenue sp. n. Nematologica, Vol.41, no.1-4 (Jan. 1, 1995), pp. 35-50.

[0378] Thomas, D. N. Frozen Oceans: The Floating World of Pack Ice. Buffalo, NY, Firefly Books, 2004.

[0379] Thomas, D. N., Fogg, G. E., Convey, P., Fritsen, C. H., Gili, J. M., Gradinger, R.,... and Walton, D. W. The Biology: of Polar Regions. Oxford, OUP, 2008.

[0380] Thomas, D. N., Papadimitriou, S., and Michel, C. “Biogeochemistry' of Sea Ice.” in: Thomas, D. N. and Dieckmann, G. S., Sea Ice, 2ndEd., (Wiley-Blackwell, 2010), pp. 425-467.

[0381] Timco, G. W., and Weeks, W. F. A review of the engineering properties of sea ice. Cold Regions Science and Technology, Vol. 60, no. 2 (2010), pp.107-129.

[0382] Timoshenko S., and Woinowsky -Krieger, S. Theory of Plates and Shells. New York, McGraw-Hill, 1959.

[0383] Toimil, L. J. Ice-gouged Microrelief on the Floor of the Eastern Chukchi Sea, Alaska: A Reconnaissance Survey. Open-File Report 78-693. US Geological Survey, 1978. https: / / pubs. us gs. gov / of / 1978 / 0693 / report. pdf

[0384] Tynan, C. T., Ainley. D. G., and Stirling, I. “Sea ice: A critical Habitat for Polar Marine Mammals and Birds.” in: Thomas. D. N. and Dieckmann, G. S., Sea Ice. 2ndEd., (Wiley-Blackwell, 2010), pp. 395-424.

[0385] Udevitz, M. S., Jay, C. V., Taylor, R. L., Fischbach, A. S., Beatty7, W. S., Noren, S. R. Forecasting consequences of changing sea ice availability for Pacific walruses. Ecosphere. Vol. 8, no. 11 (Nov. 2017), pp. 1-30.

[0386] Van Leeuwe, M. A., Tedesco, L., Arrigo, K. R., Assmy, P., Campbell, K., Meiners, K. M.,... and Stefels, J. Microalgal community structure and primary production in Arctic and Antarctic sea ice: A synthesis. Elementa Science of the Anthropocene, Vol. 6 (Jan. 1.2018), pp. 1-25.

[0387] Wadhams, P. Ice in the Ocean. Gordon and Breach. 2000.

[0388] Wang, M., and J. E. Overland. A Sea Ice Free Summer Arctic within 30 Years? Geophysical Research Letter V ol. 36 (2009)L07502, doi: 10.1029 / 2009GL037820.

[0389] Wang, M. and J. E. Overland. A sea ice free summer Arctic within 30 years: An update from CMIP5 models. Geophysical Research Letters, Vol. 39 (2012), LI 8501, doi: 10.1029 / 2012GL052868.

[0390] Weeks, W. On Sea Ice. Fairbanks, AK, University of Alaska Press, 2010.

[0391] Wiig, 0., Gjertz, I. and Griffiths, D. Migration of Walruses (Odobenus rosmarus) in the Svalbard and Franz Josef Land Area. Journal of Zoology, Vol. 238, no. 4 (Apr. 1996), pp. 769-784.

[0392] U. S. Fish and Wildlife Service (USFWS). Conservation Plan for the Pacific Walrus in Alaska. Marine Mammals Management. Anchorage, AK, FWS, (Jun. 1994).

[0393] Worsley, T. R., & Herman, Y. Episodic Ice-free Arctic Ocean in Pliocene and Pleistocene Time: Calcareous Nannofossil Evidence. Science, Vol. 210, no. 4467 (1980), pp.323-325.

[0394] Yurkowski, D. J., Brown. T. A., Blanchfield, P. J., and Ferguson, S. H. Atlantic walrus signal latitudinal differences in the long-term decline of sea ice-derived carbon to benthic fauna in the Canadian Arctic. Proceedings of the Royal Society B, Vol. 287, no. 1940, (Dec. 9, 2020), pp. 1-10.

Claims

CLAIMSI claim:

1. A sea ice habitat restoration system (150) for extracting pack ice (208) having a thickness (h), a characteristic length (L), and a flexural strength (of), and for depositing a sea ice slab (216) on passing pack ice (210) to form rafted pack ice (226) (228) (230), the sea ice habitat restoration system (150) configured to be mounted on an icebreaking ship (10), the icebreaking ship (10) having a design waterline (DWL), a beam (14). a bow (189). a stem (20), a longitudinal centerline (22), a starboard side (24), a port side (26), a ship longitudinal axis, (Ax), extending from the bow (18) to the stem, a ship transverse axis, (Ay), orthogonal to the ship longitudinal axis, (Ax), and a ship vertical axis, (Az). orthogonal to the ship longitudinal axis, (Ax). and the ship transverse axis. (Ay), the sea ice habitat restoration system (150) comprising:an ice rafting device (11) including:an inclined-plane ice ramp (28) supported on the icebreaking ship (10), the inclined-plane ice ramp (28) having a bow (18), a forward ice-ramp portion (42) and an aft ice-ramp portion (44); anda rafting wedge (54) having a rafting-wedge prow (56), with the aft ice-ramp portion (44) extending aftwardly from the rafting-wedge prow (56) and extending in an outboard direction from the sea ice habitat restoration ship (10),wherein:the forward ice-ramp portion (42) has a forward ice-ramp portion inlet (46), the forward ice-ramp portion (42) having a forward ice-ramp portion inlet half-width, (R) determined by a mathematical relationship based upon expected sea ice characteristics aswhere R is inlet half-width (m);h is sea ice thickness (m);or is sea ice flexural strength (Pa);pi is sea ice density (kg / m3); andg is acceleration of gravity (m / s2).and has a forward-ice-ramp-portion-shearing zone (48), the forwardice-ramp-portion-shearing zone (48) being aft of and contiguous with the forward ice-ramp portion inlet (46);the aft ice-ramp portion (44) has an outlet zone (50) aft of and contiguous with the forward-ice-ramp-portion-shearing zone (48);the inclined-plane ice ramp (28) has a vertex (62) extending from the forward ice-ramp portion inlet (46) to the rafting-wedge prow (56), the vertex (62) having a positive linear longitudinal vertex slope, (a), the vertex configured to apply a hogging moment, (M), to the extracted sea ice exceeding the flexural strength, (or), of the extracted sea ice as the extracted sea ice longitudinally traverses the forward ice-ramp portion (42);the inclined-plane ice ramp (28) has an ice-ramp portion (30) (32) with a transverse slope, (5). and the transverse slope, (o) progressively increases downwardly from the bow (18) tow ard the stem (20); andthe rafting wedge (54) has a rafting wedge w all (58) (60) extending beyond a side (24) (26) of the inclined-plane ice ramp (28), and the rafting wedge wall (58) (60) has a rafting wedge wall width. (W), determined by a mathematical relationship:W ~D + R 2wftere D is an offset distance for depositing the rafted ice and is a mean of an offset distance Dcr-vmax for a fully cracked condition and an offset distance Dei-vmax for an uncracked, fully elastic condition.

2. The sea ice habitat restoration system (150) of claim 1, wherein the inclined-plane ice ramp (28) has a port ice-ramp portion (30) and a starboard ice-ramp portion (32), the port ice-ramp portion (30) having a forward port ice-ramp portion (34) and an aft port ice-ramp portion (36), the starboard ice-ramp portion (32) having a forward starboard ice-ramp portion (38) and an aft starboard ice-ramp portion (40), the forward port ice-ramp portion (34) and the forward starboard ice-ramp portion (38) forming the forward ice-ramp portion (42), the aft port ice-ramp portion (36) and the aft starboard ice-ramp portion (40) forming the aft ice-ramp portion (44); andwherein the rafting wedge (54) bisects the aft ice-ramp portion (44) into the aft port ice-ramp portion (36) and the aft starboard ice-ramp portion (40), the aft port ice-rampportion (36) extending from the rafting-wedge prow (56) aftwardly along a port side of the inclined-plane ice ramp (28) and cantilevered outboard from the port side (26) of the sea ice habitat restoration ship (10), the aft starboard ice-ramp portion (40) extending from the rafting- wedge prow (56) aftwardly along a starboard side of the inclined-plane ice ramp (28) and cantilevered outboard from the starboard side (26) of the icebreaking ship (10),each of the port ice-ramp portion (30) and the starboard ice-ramp portion (32) has the transverse slope, (8), and the transverse slope, (6) progressively increases downwardly from the bow (18) toward the stem (20); andthe rafting wedge (54) has a port rafting wedge wall (58) extending beyond the port side of the inclined-plane ice ramp (28) and a starboard rafting wedge wall (60) extending beyond the starboard side of the inclined-plane ice ramp (28), the port and starboard rafting wedge walls (58) and (60) have the rafting wedge wall width, (W), determined by the mathematical relationship:W ~D + R 2where D is the offset distance for depositing the rafted ice and is the mean of the offset distance Dcr-vmax for a fully cracked condition and the offset distance Dei-vmax for the uncracked, fully elastic condition.

3. The sea ice habitat restoration system (150) of claim 2, wherein the inclined-plane ice ramp (28) is symmetrical with respect to the ship longitudinal axis (Ax).

4. The sea ice habitat restoration system (150) of claim 2 or claim 3. wherein the inclined-plane ice ramp (28) is cantilevered outboard of a side of the icebreaking ship (10) to deposit ice beyond a bounding edge of a channel (236) formed by the icebreaking ship (10).

5. The sea ice habitat restoration system (150) of any one of claims 1-4, wherein the ice rafting device (11) includes a linkage (151) configured to support the inclined-plane ice ramp (28) for movement between a stowed position and a working position with respect to the icebreaking ship (10).

6. The sea ice habitat restoration system (150) of claim 5, wherein the ice rafting device (11) comprises:a forw ard linkage axle (152) configured to be attached to the icebreaking ship (10); an aft linkage axle (156) configured to be attached to the icebreaking ship (10); a forward linkage arm (170) pivotably supported on the forward linkage axle (152) and pivotably engaged with the inclined-plane ice ramp (28); andan aft linkage arm (172) pivotably supported on the aft linkage axle (156) and pivotably engaged with the inclined-plane ice ramp (28).

7. The sea ice habitat restoration system (150) of claim 6, wherein the linkage (151) comprises a four-bar linkage including the forward linkage arm (170), the aft linkage arm (172), the inclined-plane ice ramp (28), and the icebreaking ship (10).

8. The sea ice habitat restoration system (150) of claim 7, further comprising:a center aft anchor (153) secured to the inclined-plane ice ramp (28);a center forward anchor (157) secured to the inclined-plane ice ramp (28);an anchor stay (158) secured to the icebreaking ship (10); anda locking element (159) configured to engage the anchor stay (158) and at least one of the center aft anchor (153) and the center forward anchor (157) to secure the inclined-plane ice ramp (28) to the icebreaking ship (10).

9. The sea ice habitat restoration system (150) of claim 8, wherein the anchor stay (158) is configured and located to engage the locking element (159) and the center aft anchor (153) when the inclined-plane ice ramp (28) is in the stowed position, and to engage the locking element (159) and the center forward anchor (157) when the inclined-plane ice ramp (28) is in the working position.

10. The sea ice habitat restoration system (150) of any one of claims 8-9, wherein the anchor stay (158) includes a fork assembly, and the locking element (159) includes a loadbearing pin driven by an actuator to engage the fork assembly and a selected one of the center aft anchor (153) and the center forward anchor (157).

11. The sea ice habitat restoration system (150) of any one of claims 1-10, wherein the inclined-plane ice ramp (28) is a ruled surface bounded by a lower bounding curve (64) and an upper bounding curve (66) and rulings of the ruled surface are oriented about 90° transverse to a ship longitudinal axis, (Ax).

12. The sea ice habitat restoration system (150) of claim 11, wherein:the lower bounding curve (64) is formed by an intersection of a horizontally oriented surface (68) and a vertically oriented surface (70).the horizontally oriented surface (68) is extruded from a first curve (72) on the longitudinal axis, (Ax), of the icebreaking ship (10), the first curve (72) having a forward portion (74) and an aft-portion (80), the forward portion (74) inclined at a slope (76) of about 10° over a length of about 14.4 m, the aft-portion (80) inclined at a slope of about negative 2° having a length of about 6.8 m via an arc (78) having a radius of curvature of about 30 m and a cord of about 6.3 m, the forward portion (74) transitioning to the aft-portion (80),the vertically oriented surface (70) is extruded from a second curve (82) in a horizontal plane, the second curve (82) having a forward portion (84), a mid-portion (86) and an aft-portion (90).the forward portion (84) being a portion of an ellipse with a major axis of about 10.83 m and a minor axis of about 5.50 m, the major axis parallel to the mid-portion (86), the forward portion (84) transitioning tangentially at a co-vertex of the ellipse to the mid-portion (86),the mid-portion (86) having a slope of about 30° over a length of about 15.72 m, the mid-portion (86) transitioning to the aft-portion (90) via a portion of an ellipse (88) having a major axis parallel to the mid-portion and about 6.21 m and a minor axis of about 4.24 m, the aft-portion (90) being a line segment having a slope of about 82° from the major axis of the ellipse (88) and having a length of about 3.67 m.the upper bounding curve (66) is formed by an intersection of a frustum (92) of a right circular cone with a sinusoidal surface (94) extruded from the sinusoidal curve,a top (96) of the frustum (92) has a radius of about 25 m with a draft angle (98) of about 21° and is centered about 25 m off the ship longitudinal axis (Ax) and is offset aft of the icebreaking ship bow (18) about 5.86 m, andthe sinusoidal surface (94) is extruded along the ship transverse axis (Ay) from a curve (100) having an aft portion (102) defined by a sine wave z = -7cos(2nx / 62) joined at the base of the rafting-wedge prow (56) to a forward portion (104) defined by a line coincident with the vertex (62) and having a slope of about 21° tangentially joining the sine wave.

13. The sea ice habitat restoration system (150) of any one of claims 1-12, wherein the positive linear longitudinal vertex slope (a) is about 21°, and the transverse slope 5 of the progressively increases from about zero at the bow (18) to about negative 15°.

14. The sea ice habitat restoration system (150) of claim 13, wherein the rafting wedge wall width (W), is determined by a mathematical relationship—D + R'2.and a preferred offset distance (D), determined as the mean of the offset distance (Dcr-vmax) for a fully cracked condition and the offset distance (Dei-vma ) for an uncracked, fully elastic condition such that:D Dcr-vmax + Del-vmax )■whereDcr-vmax = 7T lc. andDel-vmax = R 2 10 Sinh3[^(60- Ic ) / 120] COS2[7t(60-lc) / 120]and where a characteristic length (lc) in meters is determined by the mathematical relationshipk = [Eh3 / 12pg (1 - v2)]I / 4andwhere:lc is characteristic length (m);h is mean design ice thickness (m);p is seawater density (kg / m3);g is acceleration of gravity (m / s2);E is ice elastic modulus (Pa);v is Poisson’s ratio, andR is inlet half-width (m).

15. The sea ice habitat restoration system (150) of any one of claims 1-14, wherein the rafting wedge (54) has a half angle, (c), about 25°. and the wedge prow (56) and the rafting wedge wall (58, 60) has a negative vertical slope (y), less than about 85° and greater than about 75° with respect to an adjacent ramp surface, and an arclength extending beyond the beam (14) of the icebreaking ship (10), a radius of curvature corresponding to a portion of a right circular cone.

16. The sea ice habitat restoration system (150) of any one of claims 1-15, wherein the bow (18) of the inclined-plane ice ramp (28) has a leading edge (134) beveled downwardly at about 45° at a bow centerline (52) below the design waterline (DWL) and has a general shape corresponding to a truncated frustum of an ellipsoid having a pressure ridge, the bow (18) configured to break sea ice.

17. The sea ice habitat restoration system (150) of any of claims 5-16, wherein the linkage (151) is anchored to a forecastle (193) of the icebreaking ship (10).

18. The sea ice habitat restoration system (150) of any one of claims 6-17, further comprising:a drive motor configured to drive a pinion gear;an annular drive gear (180) operatively connected to the pinion gear and to a driver spur gear (174), the driver spur gear (174) being operatively connected to rotate the aft linkage arm (172);a gear train assembly (168) operatively connecting the driver spur gear (174) to an idler spur gear (175), the idler spur gear (175) being operatively connected to a follower spur gear (176), and the follower spur gear (176) being operatively connected to rotate the forward linkage arm (170).

19. The sea ice habitat restoration system (150) of any one of claims 5- 18, further comprising a retractable side anchor assembly (160) configured to be retractably attached to the icebreaking ship (10) in a recessed housing (164) in a hull of the icebreaking ship (10) and to extend into a supporting position to support the inclined-plane ice ramp (28).

20. The sea ice habitat restoration system (150) of claim 19, further comprising:a retractable side anchor base hinge (163) configured to be secured within the recessed housing (164), the retractable side anchor base hinge (163) including a trough receiver (166) configured and located for accommodating a support element protruding from an aft anchor base (161) of the inclined-plane ice ramp (28);an actuator (162) configured to operatively connect to the retractable side anchor base hinge (163) to retract the retractable side anchor base hinge (163) and to extend the retractable side anchor base hinge (163) into the supporting position.

21. The sea ice habitat restoration system (150) of claim 20, wherein the support element protruding from the aft anchor base (161) is a fixed pin (167).

22. A method (500) for restoring a sea ice habitat for ice-obligate and ice-associated species comprising steps of:navigating (510) a sea ice habitat restoration ship (10) in a marine ecosphere having pack ice (208);extracting (512) a sea ice slab (216) from the pack ice (208);hogging (514) the sea ice slab (216) by applying a bending moment (M) to the sea ice slab (216);depositing (516) the sea ice slab (216) as rafted pack ice (226, 228, 230) on passing pack ice (210) having a free edge (220) forming a bounding edge of a channel (236). the rafted pack ice being set back from the free edge (220) to form a terraced ice edge (229) facilitating semi-aquatic marine mammal haulout and access to and from a disturbance corridor (235); andforming (513) an open water channel (236), simultaneous to the extracting (512), the hogging (514), and the depositing (516), in the marine ecosphere aft of and below icebreaking ship (10).

23. A method (500) of restoring a sea ice habitat according to claim 22. wherein:the sea ice habitat restoration ship in the navigating step (510) is the sea ice habitat restoration ship (10) of any one of claims 1 through 19, wherein:the extracting step (512) extracts the sea ice slab (216) using the forward ice-ramp portion (42);the hogging (514) cracks the sea ice slab (216) under its own weight with the vertex (62) of the forward ice-ramp portion (42) as the sea ice slab (216) longitudinally traverses the forward ice-ramp portion (42);the depositing (516) deposits the sea ice slab (216) as rafted pack ice (226, 228, 230) on passing pack ice (210) having a free edge (220) forming a bounding edge of the open water channel (236), the rafted pack ice being set back from the free edge (220) to form a terraced ice edge (229);the forming (513) creates an open water channel (236), simultaneous to the extracting (512), the hogging (514), and the depositing (516), in a portion of the marine ecosphere aft of the icebreaking ship (10).

Images