Watercraft with battery ballast system

Abstract

A watercraft is shown and described with a battery ballast system. The battery ballast system includes a plurality of carriage assemblies, each including a plurality of stages along the vessel's height axis and each movable along the vessel's longitudinal axis. The batteries are mounted on movable supports that are movable along the vessel's transverse axis. Each stage is loaded with less than 50% batteries and battery supports so that the batteries in each stage may be moved along the vessel's transverse axis relative to the vessel's hull in a manner that affects the vessel's heel. The carriage assemblies occupy a portion of their movable length such that they may move along the vessel's longitudinal axis relative to the vessel's hull to affect the vessel's trim. In a particular example, the watercraft's potable water system is used to change the total amount of ballast on the watercraft by changing the total weight of treated water on board, such as by discharging treated water overboard or by changing the proportion of untreated water fed to the potable water system.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 001,305, filed March 28, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE This disclosure relates to ballast systems for watercraft, and more particularly to watercraft that use an array of movable batteries as ballast. [Background technology]

[0003] Many watercraft use a form of ballast to improve stability. Ballast is usually some sort of repositionable weight that can be selectively placed on board the vessel to adjust trim, list, and / or draft. Ballast is important not only to prevent the vessel from capsizing, but also for the safety and comfort of passengers and the stability of cargo. Rough seas and shifting cargo can upset the vessel's stability, and ballast is used to offset the effects on stability.

[0004] Water is a common form of ballast because it is readily available. A typical ballast water system includes a series of tanks in the bottom of a ship's hull, strainers, pumps, distribution pipes, a treatment system, and a discharge system. The tanks are usually segregated so that ballast water can enter or exit the ship in a manner that affects the relative ballast water loading fore and aft of the ship's centerline along the ship's longitudinal axis and / or to port and starboard of the centerline along the ship's transverse axis. In addition to adjusting the relative loading, the total amount of ballast water on board the ship can be increased or decreased, which tends to change the ship's draft, i.e., the distance from a point on the keel to the waterline. The term "trim" refers to the relative draft at the bow and stern. If the draft is greater at the stern than at the bow, the ship has a positive bow trim and a negative stern trim.

[0005] One significant drawback of ballast water systems is that they are a source of invasive species, such as zebra mussels, sea lampreys, and spiny water fleas. Invasive plant species, such as Eurasian milfoil, can also be introduced. Various international, national, and regional laws influence whether and to what extent ballast water is discharged. The International Convention for the Control and Management of Ships' Ballast Water and Sediments requires ships to meet stricter invasive species standards, which will require the installation of new ballast water management systems (BWMS) within the next five years. In many cases, the standards are expected to be cost-prohibitive. Furthermore, retrofit efforts are expected to exceed the capacity of current dry docks, forcing many ships into decommissioning.

[0006] Ships often carry large quantities of batteries used to power instruments and equipment. Theoretically, batteries constitute discrete units of mass that could be selectively deployed within the ship to maintain stability. However, no reliable and automatic means of relocating them has been proposed. Furthermore, batteries cannot be added or discarded at sea to increase or decrease the ship's total ballast weight. Therefore, there is a growing need for battery ballast systems. Furthermore, some existing ships have insufficient available space to accommodate the number of batteries necessary to provide significant ballast. Therefore, there is a growing need for ships designed to accommodate battery ballast systems. Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION It is an object of the present invention to provide a watercraft having a battery ballast system. [Means for solving the problem]

[0008] According to a first aspect of the present disclosure, there is provided a watercraft comprising a hull, a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, an air storage tank in selective fluid communication with the air motor, an air compressor operable to selectively supply compressed air to the air storage tank, and ballast including a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along at least one of a longitudinal axis of the vessel and a transverse axis of the vessel. In the first embodiment, the batteries are selectively positionable along the longitudinal axis of the vessel and the transverse axis of the vessel. In the same or other embodiments, the watercraft further comprises a battery-ballast system including a carriage system and a plurality of batteries, the carriage system including a plurality of carriage assemblies, each carriage assembly including a plurality of stages, each stage including a pair of tracks, the carriage system further including a plurality of battery supports, each battery support engaging a corresponding one of the pair of tracks and movable relative to the hull along the corresponding one of the pair of tracks.

[0009] According to a second aspect of the present disclosure, there is provided a watercraft comprising a hull, a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, and an air compressor operable to supply compressed air to the air motor, wherein the watercraft does not include a fossil fuel engine or a fossil fuel tank, and the ballast comprises a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along at least one of a longitudinal axis of the vessel and a transverse axis of the vessel. In the first embodiment, the batteries are selectively positionable relative to the hull along the longitudinal axis of the vessel and the transverse axis of the vessel. In the same or another embodiment, the watercraft further comprises a battery ballast system including a carriage system and a plurality of batteries, the carriage system comprising a plurality of carriage assemblies, each carriage assembly including a plurality of stages, each stage including a pair of tracks, the carriage system further comprising a plurality of battery supports, each battery support engaging a corresponding one of the pair of tracks and movable along the corresponding one of the pair of tracks relative to the hull.

[0010] According to a third aspect of the present disclosure, there is provided a watercraft comprising a hull, a propeller operable to propel the watercraft through a body of water, and a battery ballast system including a carriage system and a plurality of batteries, the batteries of which are selectively positionable relative to the hull along a longitudinal axis of the vessel and a transverse axis of the vessel. According to a first embodiment, the carriage system includes a plurality of carriage assemblies, each carriage assembly including a plurality of stages, each stage including a pair of tracks, and the carriage system further includes a plurality of battery supports, each battery support engaged with a corresponding one of the pair of tracks and movable relative to the hull along the corresponding one of the pair of tracks. In the same or other embodiments, the battery supports are movable relative to each other along the transverse axis of the vessel. In the same or other embodiments, the carriage assemblies are movable relative to the hull along the longitudinal axis of the vessel.

[0011] According to a fourth aspect of the present disclosure, there is provided a method of adjusting trim for a watercraft having bow and stern defining longitudinal axes, the method including providing a battery ballast system including a carriage system and a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along the vessel's longitudinal axis and the vessel's transverse axis, and selectively moving a subset of the plurality of batteries along the longitudinal axes relative to the hull.

[0012] According to a fifth aspect of the present disclosure, there is provided a method of adjusting heel of a watercraft having a hull and port and starboard sides defining a transverse axis, the method including providing a battery ballast system including a plurality of batteries and a plurality of stages, each stage including a plurality of battery supports movable relative to the hull along the transverse axis, and selectively moving a subset of the plurality of batteries along the transverse axis of the vessel.

[0013] According to a sixth aspect of the present disclosure, there is provided a method of adjusting a draft of a watercraft having a potable water system having an untreated water inlet in fluid communication with a desalination unit and a fresh water tank in fluid communication with the desalination unit, the method comprising adjusting a volume of fresh water in the fresh water tank. [Brief explanation of the drawings]

[0014] The present disclosure will now be described, by way of example only, with reference to the accompanying drawings.

[0015] [Figure 1] FIG. 1 is a side view of a watercraft used to explain the determination of a vessel's draft and trim. [Figure 2] FIG. 2 is a schematic rear view of a watercraft used to explain determining the heel of the watercraft. [Figure 3A] FIG. 3A is a cross-sectional view of a watercraft with a battery ballast system taken along a direction parallel to the length of the vessel. [Figure 3B]FIG. 3B is a cross-sectional view of a watercraft with a battery-ballast system taken along a direction parallel to the vessel's vertical axis. [Figure 4] FIG. 4 is a perspective view of a portion of the carriage assembly of the battery ballast system of FIGS. 3A and 3B. [Figure 5] FIG. 5 is an exploded view showing the structure of the battery support mounted on the rails of the carriage assembly of the battery ballast system of FIGS. 3A and 3B. [Figure 6A] FIG. 6A is a schematic diagram illustrating a drinking water system used in the watercraft of FIGS. 3A and 3B. [Figure 6B] FIG. 6B is a schematic diagram illustrating an exemplary control scheme using the potable water system of FIG. 6A to control the total ballast of a watercraft. [Figure 7] FIG. 7 is an air and electric propulsion system for a watercraft without a fossil fuel engine or fossil fuel tank, suitable for use on a watercraft with a battery ballast system. DETAILED DESCRIPTION OF THE INVENTION

[0016] The drawings show an example of a watercraft having a battery ballast system. Based on the above, it should be generally understood that the nomenclature used herein is merely for convenience, and that the terms used to describe the present invention should be given their broadest meaning by those skilled in the art. Unless otherwise specified, like numerals refer to like components herein.

[0017] Referring to FIG. 1, a watercraft 10 is shown. The watercraft 10 comprises a hull 20 including a bow 22 and a stern 24 and a keel 26. The distance between the bow 22 and the stern 24 defines a longitudinal axis L of the watercraft. A rudder 32 projects away from the keel 26 and is used to steer the watercraft 10. The watercraft 10 comprises at least one propeller operable to propel the watercraft 10 through the water. In FIG. 1, the at least one propeller is propeller 52a and propeller 52b (not shown in FIG. 1). Propeller 52a is spaced from the keel 26 and positioned below the waterline 34 (when the watercraft 10 is in water). The distance from the keel 26 to the waterline 34 along a vertical axis H defines the watercraft's draft.

[0018] As shown in FIG. 1, the watercraft 10 may have a draft that varies along its longitudinal axis. The variation in draft between the bow 22 and the stern 24 is characterized as the trim of the watercraft. Draft is the vertical distance from any part of the keel to the waterline, i.e., perpendicular to the waterline and the water surface. F ) and stern (H A The difference in draft at the bow and stern is known as "trim." "Bow trim" is the difference in feet of draft at the bow and stern, as shown in equation (1). (1) Bow trim = H F -H A where H F = Draft at bow (feet) H A = draft at stern (feet)

[0019] "Stern trim" is the difference in feet of draft at the stern and bow, as shown in equation (2): (2) Stern trim = H A -H F

[0020] In general, it is customary to state trim as a positive value. A HF If it is greater than H, the trim is described as positive aft trim. A H F If it is less than H, the trim is described as positive bow trim. A H F The vessel is on even keel when the trim is equal to ≈ 0.05. The trim can be affected by water conditions, cargo load, and vessel design. As previously mentioned, ballast is typically adjusted along the longitudinal axis of the watercraft 10 to achieve the desired trim.

[0021] 2A and 2B show schematic diagrams of the stern 24 of the watercraft 10, used to illustrate the heel of the watercraft 10. In FIG. 2A, the watercraft 10 is upright, with its center of gravity and center of buoyancy collinear with the vertical axis (i.e., an axis perpendicular to the Earth, the water surface, and the waterline W). Thus, the watercraft 10 has a zero heel angle. In FIG. 2B, an external disturbance has caused the watercraft 10 to heel to starboard, with its center of gravity and center of buoyancy collinear with the vertical line in FIG. 2A and a line defining the heel angle θ. As previously mentioned, ballast can be adjusted along the spanwise axis of the watercraft 10 to adjust the heel angle θ.

[0022] 3A and 3B, a vessel 200 is shown having a hull 201 and a battery ballast system 211. The battery ballast system 211 is preferably located on a lower deck 210 below the main deck (not shown) along the vessel's height axis H. The lower deck 210 has a starboard bulkhead 202 and a port bulkhead 204 spaced apart along the vessel's width axis. In FIG. 3A, the battery ballast system 211 is shown below the main deck and cargo hold 206, and below a potable water system deck 208 that houses part of the vessel's potable water system, one embodiment of which is described below with reference to FIG. 6A. Purified potable water is located on deck 212.

[0023] The battery ballast system 211 includes a carriage system including a plurality of carriage assemblies 214-244 (FIG. 3B). Each carriage assembly 214-244 includes a plurality of batteries 292. The carriage assemblies 214-244 are selectively movable along the vessel's longitudinal axis to adjust the vessel's ballast along the vessel's longitudinal axis. Each carriage assembly 214-244 includes a plurality of stages disposed along the vessel's elevation axis. Each stage includes a pair of tracks and a plurality of battery supports, each battery support engaging with and movable along a corresponding one of the pair of tracks.

[0024] Carriage assembly 214 is shown schematically in FIG. 3A. Each carriage assembly 214-244 has the same structure in the illustrated embodiment, although different structures may be used. Carriage assembly 214 includes eight stages AH arranged along the vessel's elevation axis H. The same stage numbering scheme applies to the stages of carriage assemblies 216-244. The stages AH are spaced apart along the elevation axis in FIG. 3 for clarity, but in practice are connected to define the integral carriage assembly 214.

[0025] Each tier AH includes 50 slots, which are positions that can accommodate batteries 292. The slots are arranged along the transverse axis of the ship. Slots 1-50 are fixed positions within the carriage assembly. Different batteries 292 may be relocated to different slots. Batteries 292 are located on battery supports (described below) that move along the tracks of their respective tiers and along the transverse axis of the ship. As described in more detail below, the battery supports are generally I-shaped members, the ends of which slidably engage the rails of their respective tiers of carriage assemblies. In certain embodiments, each battery and the corresponding battery support (described below) on which it is located are independently movable along the transverse axis of the ship. However, in other examples, individual batteries are grouped and moved together, such as in groups of 5, 10, 15, or 20 batteries. Grouping batteries in this manner provides some flexibility in placing batteries where needed, but simplifies the motor assembly required to move the battery supports.

[0026] Preferably, the number of battery supports in a given stage AH is less than the number of slots 1-50 in the stage. Otherwise, the batteries 292 in that stage cannot be relocated along the transverse axis to change the heel angle θ (FIG. 2B). All batteries 292 may be moved along the transverse axis toward or away from the starboard bulkhead 202 and the port bulkhead 204. A subset of batteries 292 may be moved along the transverse axis (Mw) from one side of the midship to the other. The number of batteries in a subset depends on the slot installation. In the example of FIG. 3A, nine of the 32 batteries in each stage may be moved along the transverse axis from one side of the midship to the other.

[0027] The number of open slots 293 (slots without battery supports) in a given tier AH is preferably about 30% to about 50% of the total slots in the tier, more preferably about 35% to about 45% thereof, and even more preferably about 34% to about 38% of the slots in a given tier. In Figure 3A, slots H(10)-H(41) of tier H are occupied by carriage assemblies 214, while slots H(1)-H(9) and H(42)-H(50) are unoccupied.

[0028] As shown in Figure 3A, different stages AH can have similar or different battery 292 mounting arrangements. Stage AD has batteries 292 and battery supports only in slots 1-16 and 35-50, while stage EH has batteries and battery supports only in slots 10-41. As an example of how batteries 292 may be repositioned to change the heel angle θ, if the vessel 200 has the orientation shown in Figure 2B, moving the batteries 292 from the starboard side to the port side of the transverse axis centerline Mw will tend to return the watercraft 10 to the upright position of Figure 2A.

[0029] Referring to FIG. 3B, each upper tier H of carriage assemblies 214-244 is shown. The configuration of batteries 292 and slots 1-50 in tier H of carriage assembly 214 in FIG. 3B differs from FIG. 3A. Sixteen carriage assemblies 214-244 are shown in FIG. 3B. However, depending on the vessel 200, more may be provided. As shown, each carriage assembly 214-244 is selectively movable along the vessel's longitudinal axis relative to the hull 201. Also, as shown, the stowage configuration of batteries 292 for the upper tier H of each carriage assembly 214-244 may vary along the vessel's longitudinal axis. In carriage assemblies 214-218 and 220, slots 1-9 and 28-50 are occupied by batteries 292. In carriage assemblies 222-228, slots 1-32 are occupied. In carriage assemblies 230-234, slots 1-22 and 41-50 are occupied, and in carriage assemblies 236-244, slots 1-32 are occupied.

[0030] The number of slots, percentage of open slots per row, and number of carriage assemblies are preferably selected based on the size and weight of the battery and the desired degree of ballast on either side of the amidships position along the transverse axis (MW) and the amidships position along the longitudinal axis (ML). In some examples, the distance along the longitudinal axis occupied by the carriage assemblies 214-244 is about 60% to about 75%, preferably about 65% to about 70%, and more preferably about 66% to about 68% of the maximum available distance along the longitudinal axis. The distance occupied by the carriage assemblies 214-244 along the longitudinal axis is the distance along the longitudinal axis occupied by the carriage assemblies 214-244 when all of the carriage assemblies 214-244 are positioned in adjacent engagement with no gaps between them. The maximum available distance is the distance between the maximum forward and maximum aft positions of the two carriages closest to the bow and stern. In FIG. 3B, these carriage assemblies are 214 and 244.

[0031] Carriage assemblies 214-244 are similarly constructed. One carriage assembly 220 is shown in FIG. 4. Only the four stages of AE and a portion of carriage assembly 220 adjacent starboard bulkhead 202 are shown in FIG. 4. Stage E includes a set of parallel tracks 262, 264 extending along the transverse axis of vessel 200 and spaced apart from one another along the longitudinal axis of vessel 200. Four vertical members (not shown) are positioned at the ends of tracks 262, 264 and secured to tracks 262, 264 and to the tracks of all other stages within carriage assembly 220 by suitable mechanical fasteners, welding, or other reliable means. Battery support 261 is one of several battery supports on stage E and may also be referred to as a "carriage seat." Battery support 261 is an I-shaped member comprising a cross beam 266 extending between parallel tracks 262, 264 along the longitudinal axis of vessel 200, and end beams 267, 265 (not shown), which slidably engage with parallel tracks 262, 264, respectively, along the transverse axis of vessel 200. End beam 267 includes a vertical section 269 and a horizontal section 273. End beam 265 (not shown) is structured to engage with corresponding track 264 in a similar manner. Details of the engagement between the battery support and the tracks are shown in FIG. 5 and described further below.

[0032] Batteries 292 each rest on a corresponding battery support. In Figure 4, slots 45, 46-49 in row E are occupied. Battery support 261 is visible, but if support 261 is unoccupied, support 261 would typically be removed to allow for greater movement of other batteries in the row.

[0033] Stage D extends along the transverse axis of vessel 200 and includes parallel tracks 268, 270 spaced apart along the longitudinal axis of vessel 200. Battery support 271 extends between the parallel tracks 268, 270 along the longitudinal axis of the vessel and includes cross beams 272 and end beams 274, 276. Each end beam 274, 276 slidably engages with a respective one of the parallel tracks 268, 270 along the transverse axis of vessel 200 in the same manner as end beam 267 engages with track 262, as described above. When support 271 is occupied, battery 292 rests on cross beam 272 and end beams 274, 276.

[0034] Stage C includes parallel tracks 278, 280 and battery support 281 (with additional supports not called out). Parallel tracks 278, 280 extend along the transverse axis of vessel 200 and are spaced apart along the longitudinal axis of vessel 200. Battery support 281 is an I-shaped member with a cross beam 282 extending between parallel tracks 278, 280 along the longitudinal axis, and end beams 284, 286 that engage with each of parallel tracks 278, 280 in the same manner as end beam 267 of battery support 261 engages with track 262 and are slidable along the transverse axis of vessel 200. Slots E(50), D(50), and A(50) are not shown in FIG. 4. Carriage assembly 220, like the other carriage assemblies 214-244, preferably slidably engages a pair of rails spaced apart along the vessel's transverse axis and extending along the vessel's longitudinal axis for moving carriage assembly 220 along the vessel's longitudinal axis relative to hull 201.

[0035] Referring now to Figure 5, an exemplary battery support for the carriage assemblies 214-244 described herein is shown. In Figure 5, battery support 271 from carriage assembly 220 of Figure 4 is shown. However, it is understood that in this example, battery supports for the other carriage assemblies are similarly configured.

[0036] Each battery support of each stage AH is movable relative to the hull 201 transversely to the vessel's longitudinal axis and along the vessel's transverse axis. In this example, the battery support 271 includes a cross beam 272 attached to end beams 274, 276, as previously described. The end beam 274 includes an upper horizontal section 312 and a lower vertical section 316. Two wheels are rotatably attached to the lower vertical section 316 and are spaced apart along the vessel's transverse axis. Only the wheel 320 is shown on the lower vertical section 316. The wheel 320 is located between the lower vertical section 316 of the end beam 274 and the vertical section 306 extending above the track 268. The track 268 also includes a lower edge 302 that projects toward the other track 270 along the vessel's longitudinal axis. Wheel 320 rests on and rolls along lower edge 302, and end beam 274 slidably engages track 268 along the transverse axis of vessel 200. The other wheel (not shown) mounted on the opposite end of end beam 274 is similarly configured.

[0037] The end beam 276 also includes an upper horizontal section 314 and a lower vertical section 308. The track 270 is configured as a mirror image or as the track 268. The end beam 276 includes two wheels attached to either end of the lower vertical section. Wheel 322 is shown, but the wheel at the other end of the end beam 276 is not. The lower edge 304 functions similarly to the lower edge 302. Thus, the wheel 322 is disposed between the lower vertical section of the end beam 276 and the vertical section 308 extending above the track 270, and travels along the lower edge 304 of the track 270. Thus, the end beam 276 has two wheels at either end of the end beam 276 that roll along the lower edge 304 of the track 270, thereby allowing the end beam 276 to slidably engage with the track 270 along the transverse axis of the vessel 200.

[0038] In some examples, each battery support in a carriage assembly 214-244 is motorized along a corresponding pair of tracks. An existing motor assembly is provided and operable to move each battery support in a given stage AH of a given carriage assembly 214-244 to a desired slot position. In other examples, the battery supports are coupled in groups (such as groups of 5, 10, 15, or 20) of battery supports that move together along the transverse axis of the vessel 200 relative to the hull 201.

[0039] As shown in FIG. 5, each battery 292 is positioned and secured to the battery support 271 by, for example, four twist locks 325, 327, 329, 331 at the four corners of the battery 292, which can be coupled with openings 324, 326, 328, 330 (not shown in FIG. 4) located manually or remotely in the end beams 274, 276 of the battery support 271. While the battery support 271 is shown with openings 324, 326, 328, 330 for mating with the twist locks 325, 327, 329, 331 of the battery support 271, it should be understood that the battery support 271 can also be provided with twist locks that mate with corresponding openings in the battery 292. Similar twist locks can also be provided on either the battery supports to interlock adjacent battery supports or to couple the batteries together while the vessel is in motion.

[0040] In a preferred embodiment of the battery and ballast system 211 described herein, an existing motor assembly is provided to drive each battery support 271 on each tier AH along the tracks 268, 270. Additionally, a motor assembly control system comprising an existing remote control may be provided to allow a user to operate the battery ballast system 211 outside the deck on which the battery ballast system 211 is located. Thus, the user can drivably move the battery 292 to the desired slot on each tier. These existing mechanisms are typically provided to achieve proper alignment of the battery support 271 within each tier for storage and retrieval operations. The remote control motor assembly may be mounted, for example, within the cross beam 272 of each battery support 271.

[0041] Thus, in one embodiment, each individual battery support is independently drivable, and the remote motor control is provided with an existing selection device for independently driving each battery support 271, independent of the other battery supports. When ballast adjustment is required in a particular tier, a user can individually drive each battery support into the appropriate slot to affect the vessel's list and / or trim. In one embodiment, each battery support is assigned a unique identifier, and each slot is assigned a unique identifier, which can be remotely actuated to move a particular battery support to a particular slot. Of course, depending on the number of battery supports in a tier, not all slots in a given tier will have access to all battery supports. For example, each tier may have 32 battery supports, identified as S(1)-S(32). In the tier shown in FIGS. 3A and 3B, the S(1) support can be positioned in any of slots 1-32. The S(2) battery support can be positioned in any of slots 2-33, etc. In other words, the number of available slots in each tier is equal to the number of different slots a given battery support 271 can occupy in that tier. However, the particular slot that a given battery occupies depends on the battery's position relative to other batteries in the same tier. In other examples, battery supports can be grouped as described above. They can also be selectively grouped using a suitable mechanism for connecting adjacent battery supports 271 together, such as an electromagnetic coupling system, an electromotive coupling system, or a mechanical coupling system (e.g., a system of hooks connecting adjacent battery supports 271).

[0042] In some examples, each carriage assembly 214-244 is motor-driven along its track (not shown) and along the vessel's longitudinal axis. The total length of the available area not occupied by a carriage assembly divided by the length of each carriage assembly (along the vessel's longitudinal axis) determines the number of carriage assembly locations that a particular carriage assembly can occupy. For example, if the carriage track extends 600 feet along the vessel's longitudinal axis and each carriage assembly is 4 feet long along the vessel's longitudinal axis, there are effectively 150 carriage assembly positions along the vessel's longitudinal axis. If 100 carriage assemblies are provided, the total usable length of all carriage assemblies is 400 feet, with 200 feet unoccupied. In this case, each carriage assembly can use 50 different carriage assembly positions along the vessel's longitudinal axis. In other examples, adjacent carriage assemblies may be coupled or selectively coupled for movement as a group along the vessel's longitudinal axis relative to the hull 201.

[0043] In one example, the total weight (or mass) of the battery-ballast system 211 is approximately 20 to 30 percent of the deadweight tonnage of the vessel 200. "Deadweight tonnage" is a measurement of the total contents of the vessel, including cargo, fuel, crew, passengers, provisions, and water, excluding boiler water. In the same or other examples, each slot of the carriage assembly (including the battery supports, but excluding the batteries) weighs approximately 15 to 25 pounds, preferably approximately 17 to 23 pounds, and more preferably approximately 18 to 21 pounds. In the same or other examples, the batteries 292 weigh approximately 100 to 200 pounds, preferably approximately 120 to 180 pounds, and more preferably approximately 140 to 160 pounds.

[0044] Unlike a ballast water system, the battery ballast system 211 cannot add or remove batteries 292 while at sea. Thus, while it can be repositioned along the vessel's longitudinal and transverse axes, the total weight of battery ballast on board the vessel 200 cannot be changed while the vessel 200 is at sea. In one embodiment, the amount of potable water produced by the vessel 200's potable water system is varied, effectively creating an additional source of ballast. In certain embodiments, the vessel's potable water system is used to change the vessel's total ballast weight by varying the total amount of treated water on board, such as by discharging treated water overboard or by changing the proportion of untreated water supplied to the potable water system.

[0045] Referring to Figure 6A, a drinking water treatment system 340 is shown. The drinking water treatment system 340 is provided for producing fresh drinking water from seawater. The drinking water treatment system 340 includes a desalination device 341 that includes an evaporator 344 and a condenser 342. The evaporator 344 produces steam from the seawater and removes salts and other non-volatile materials. The steam is then condensed to produce drinking water.

[0046] Seawater brought in through seawater inlet 345 is pumped by ejector pump 348 into condenser cooling water inlet line 356. Coil 370 is provided within condenser 342 to provide additional surface area for heat transfer from the condensing steam to the cooling water. The cooling water exits the condenser as discharge stream 372. A portion of discharge stream 372 is recirculated to the condenser via recirculation stream 366, and the remainder of discharge stream 372 is discharged overboard in overboard discharge line 364.

[0047] The recirculation stream 366 enters the secondary cooling coil 368 in the condenser 342, providing secondary cooling to the evaporating steam. After exiting the cooling coil 368, the stream is sent to the evaporator 344 and becomes the evaporator supply steam 374. The engine jacket water provides the heat of evaporation and enters the evaporator 344 via the evaporator heating medium inlet stream 376. The evaporator heating medium inlet stream 376 enters the evaporator heating nest 380 and exits the evaporator 344 via the evaporator heating medium outlet stream 378. The heat from the engine jacket water and the pressure from the operation of the evaporator 344 cause the evaporator supply water 374 to evaporate in the evaporator 344 and enter the condenser 342. The evaporating water (steam) passes through the annular demister 358, transferring heat to the cooling water in the cooling water coils 370 and 368, causing the steam to condense in the condensate trap 360. Condensate from condensate trap 360 enters process water pump suction line 362 and is pumped by process water (fresh water) pump 354 to fresh water tank 346. In one embodiment, a level controller may be provided to control the level of condensate trap 360 and may be cascaded to condenser fresh water discharge line 355 and flow controller 392 (FIG. 6B). Flow controllers may also be provided in condenser cooling medium recirculation line 366 and / or evaporator heating medium injection line 376 or discharge line 378. While a variety of different control schemes can be used, preferably, they ensure that condensate trap 360 does not run dry and that the necessary amount of fresh water is supplied to fresh water tank 346 based on the needs on board.

[0048] In a preferred example, a portion of the volume of fresh water in the fresh water tanks 346 is used as ballast. According to this embodiment, there are no ballast water tanks that are not fluidly coupled to the potable water system 340. As previously mentioned, the battery-ballast system 211 cannot add or remove ballast while the vessel 200 is at sea. If it is desired to increase or decrease the vessel's draft at both the bow and stern, simply adjusting the position of the batteries 292 is insufficient. Therefore, in one embodiment, the potable water treatment system 340 is dimensioned so that the volume of water in the fresh water tanks 346 can be changed to provide a desired amount of total ballast variation, i.e., the amount of fresh water that can be removed from or added to the fresh water tanks 346 that corresponds to the maximum expected ballast weight change.

[0049] In some embodiments, when total ballast reduction is required, fresh water from fresh water tank 346 is discharged overboard. The volume of water corresponding to a particular mass of water discharged is given by equation (3) below: (3) V E =M E / ρ where V E = Discharge volume (gal.) M E = Discharge mass (lb m ) ρ = density of water (8.35 lb m / gal.)

[0050] Based on the dimensions of the tank, the corresponding level change can be calculated as follows (assuming a cylindrical shape): (4)ΔL=(0.5348V E ) / πD 2 where V E = Discharge volume (gal.) D = Tank diameter (ft.)

[0051] For rectangular tanks, equation (3) still applies, but instead of equation (4), the following equation is used to calculate the level change: (5)ΔL=(0.1337V E ) / (a·b) where V E = Discharge volume (gal.) a = Tank width (ft.) b = Tank length (ft.)

[0052] If a total ballast change is required, it can be done manually or automatically. In a manual implementation, if an increase in ballast is required, the flow control valve 406, if open, is first closed. If the valve 406 is already closed, or if closing it does not provide the desired amount of additional ballast, the flow rate of seawater to the drinking water treatment system 340 may be increased, for example, by opening the flow control valve 351 on the discharge side of the pump 352 (FIG. 6A) or by increasing the set point of the flow controller 353, which receives a flow measurement signal from the flow meter 355.

[0053] Various suitable control systems may be provided to allow the amount of fresh water in the fresh water tank 346 to be varied or discharged based on ballast needs. In one embodiment, a suitable control scheme is provided configured to accept or discharge a certain amount of water from the tank 346 based on ballast needs while ensuring that the condensate trap 360 does not run dry and ensuring the water level in the tank 346 remains at an acceptable level to operate the potable water pump 408, providing the ship's fresh water for cooking, bathing, laundry, and other uses via the onboard fresh water line 414. One exemplary control scheme adjusts the flow rate of onboard fresh water in the fresh water line 414 to control the water level in the tank 346 and adjusts the flow rate in the overboard discharge line 411 to vary the total amount of ballast for the ship. The fresh water line 414 and the overboard discharge line 411 are described in more detail below.

[0054] In one embodiment, the ballast change is accomplished by changing the flow rate of treated water discharged through overboard line 411. In the same or other embodiments, the ballast change is accomplished by varying the flow rate of seawater to the potable water system by adjusting the set point of flow controller 353 or adjusting valve 351 to open a desired percentage.

[0055] In a further embodiment, the desired reduction in ballast is achieved by increasing the flow rate of discharge water in the overboard line 411, and then, if necessary, reducing the flow rate of seawater injection into the drinking water treatment system 340. In the same embodiment, an increase in ballast is achieved by first reducing the amount of fresh water discharged in the overboard line 411, and then, if necessary, increasing the flow rate of seawater injection into the drinking water treatment system 340. These adjustments can be made by manually operating the valves 406, 351, or by changing the set points via the respective flow controllers 404, 353, or by using a ballast controller, such as the ballast controller 400 described below.

[0056] In another exemplary control scheme, the ballast controller adjusts the flow rate in the overboard discharge line 411 until the valve 406 is closed or until the ballast controller is overridden by a level controller controlling the water level in the tank 346, at which point the ballast controller adjusts the setpoint of the flow controller 353 (FIG. 6A) to adjust the seawater injection rate into the potable water system 340. Because ballast changes are often discrete, if a decrease in ballast is required, in this example the ballast controller first attempts to increase the flow rate of ballast water in the overboard line 411 and then decreases the seawater injection rate into the potable water treatment system 340. In this example, if an increase in ballast is required, the ballast controller first attempts to decrease the flow rate in the overboard line 411 and then increases the seawater injection rate into the potable water treatment system 340, if necessary.

[0057] Referring to Figure 6B, the water level in tank 346 must generally be maintained to provide sufficient net suction head to pump 408, which can constrain the extent to which the desired ballast exchange can be achieved using the opening and closing of valve 406. In Figure 6B, an exemplary control system is provided that addresses both level control and ballast control of tank 346. The illustrated control scheme controls the vessel's total ballast loading by adjusting the flow rate of discharge water in overboard line 411. A desired change in total ballast over a desired period of time may be translated into a flow rate in overboard discharge line 411, as follows: (6)F 411 =(W E / ρ) / Δt where F 411 = flow rate of line 411 (gal / hour) W E = total desired ballast replacement (lbs.) ρ = density of water (8.35 lb. / gal.) Δt = time interval between ballast changes (hours)

[0058] Pump 408 pumps fresh potable water from tank 346 to overboard discharge line 411 and onboard fresh water line 414. Overboard discharge line 411 directs fresh water from tank 346 overboard and is used to adjust the total amount of ballast by discharging fresh water overboard if ballast reduction is required or by throttling the amount of water sent overboard if ballast increase is required.

[0059] The flow rate in the overboard discharge line 411 is controlled by a flow controller 404, which adjusts a control valve 406 based on the flow rate measured by a flow meter 402. An onboard fresh water line 414 delivers fresh water to showers, bathrooms, laundry rooms, kitchens, and other areas requiring fresh water. The flow rate of fresh water in the onboard fresh water line 414 is controlled by a flow controller 413, which adjusts a control valve 412 based on the flow rate measured by an onboard fresh water flow meter 410. Although not shown, a recycle line may be provided downstream of the control valve 412 to allow fresh drinking water not needed by onboard users to be recycled to the fill line 355 of the tank 346.

[0060] A ballast controller 400 is provided to adjust the flow rate in the overboard discharge line 411 by resetting the set point of the flow controller 404, thereby changing the total amount of vessel ballast according to equations (3) and (4). As shown in FIG. 6, the ballast controller 400 receives a level indication from the level transmitter 396 and uses the level indication to determine the current volume and weight of fresh water in the tank 346. The ballast controller 400 receives a user-entered set point corresponding to the amount of ballast, or the change in the total amount of ballast in the tank 346, and the time interval between ballast changes (the ballast provided by the battery 292 can only be moved within the vessel; it cannot be increased or decreased while at sea). Once the total ballast set point is entered, the ballast controller 400 calculates the ballast change required to achieve that set point. In either case, the ballast controller 400 includes an algorithm that converts the desired change in total ballast weight and the time frame for making the user-entered change into a flow rate for the overboard water flow 411 according to equation (6). The ballast controller 400 adjusts the set point of the flow controller 404 to the determined set point to send fresh water overboard via the overboard discharge line 411 until the desired amount of total ballast is achieved or until the desired change in ballast is achieved, at which point the ballast controller resets the set point of the flow controller 404 to zero. The ballast controller 400 may also gradually ramp the set point of the flow controller 404 to provide a smoother change in ballast.

[0061] The level controller 398 receives a level indication signal from the level transmitter 396 in the tank 346 and resets the set point of the flow controller 413 to maintain the desired level of fresh water in the tank 346. During normal, steady-state operation, the overboard discharge line control valve 406 preferably remains closed to avoid wasting purified water. Thus, the level controller 398 typically regulates the flow rate of the onboard fresh water line 414 by adjusting the set point of the flow controller 413 to maintain the desired level in the fresh water tank 346. However, if the control valve 412 is fully open and the level in the tank 346 continues to rise, the level controller 398 preferably increases the set point of the discharge line flow controller 404 to send fresh water overboard until the level in the tank 346 reaches its set point. Alternatively or additionally, the level controller 398 may first reset the flow controller 353 (FIG. 6A) and then reset the set point of the flow controller 404 to reduce the amount of seawater entering the drinking water treatment system 340 and stop the level in the tank 346 from increasing. The flow of fresh water to tank 346 is controlled by flow controller 392, which adjusts control valve 391 based on the flow measured by inlet flow meter 390. Flow controller 392 is reset by level controller 394, which controls the level in condensate trap 360. Condensate trap 360 is provided with a level indicator, not shown in FIG. 6A. As the setpoint of flow controller 353 changes, the level in condensate trap 360 changes, and condensate tray level controller 394 adjusts the inlet flow rate setpoint of flow controller 392 to stabilize the level in tank 346.

[0062] In embodiments in which the level controller 398 overrides the ballast controller 400 and adjusts the set point of the flow controller 404 to control the level in the tank 346, a high signal selector 403 is provided to select the higher output signal between the level controller 398 and the ballast controller 400. This override function preferably occurs only after the onboard fresh water flow control valve 412 is fully open. Thus, the level controller 398 is preferably configured as a split range controller, adjusting the set point of the flow controller 413 in the onboard fresh water line 414 for an initial portion of its output range, e.g., 0 to 50 percent, and sending an output signal to the high signal selector 403 to adjust the set point of the flow controller 404 in the overboard discharge line 411 as needed for a second portion of the set point of the flow controller 413, e.g., greater than 50 percent to 100 percent. As previously mentioned, a three-part range may be used where the level controller opens valve 412 from 0 to 33 percent of the level controller 398 output signal, closes valve 351 (FIG. 6A) from 33 to 66 percent, and then opens valve 406 from 67 to 100 percent. Valve adjustments may be made directly or by resetting the flow controller 353, 413, 404 setpoints.

[0063] The controller shown in FIG. 6B may be implemented in software or hardware and may be digital or analog. Appropriate transducers may be provided to convert electrical signals to pneumatic signals, or vice versa, as needed. In one embodiment, the set point of the ballast controller 400 is manually adjusted by the crew to achieve the desired total amount of ballast on board. However, if draft measurement devices or draft estimation techniques are used, an advanced ballast control scheme may be provided that automatically adjusts the set point of the ballast controller 400. For example, the advanced control scheme may include a draft controller that allows a user to input the total amount of draft at a location along the hull, or the average draft and draft values at multiple locations, and then reset the ballast controller set point as needed to achieve the desired draft.

[0064] In one embodiment of a watercraft with a battery-ballast system, the watercraft lacks water ballast tanks other than fresh water tanks that form part of the vessel's potable water system. In many existing watercraft, the volume of the hull consumed by ballast water tanks leaves insufficient space for a battery-ballast system with sufficient batteries to provide meaningful ballast regulation. Therefore, in some cases, it is preferable that the watercraft 10 lack water ballast tanks, except to the extent that the tanks serve the dual purpose of holding treated potable water for use on board the vessel, as in the case of tank 346. In other words, in such cases, it is preferable that the watercraft 10 lacks ballast water tanks that are not in fluid communication with the fresh potable water system 340.

[0065] According to another example, a watercraft is provided with a battery-ballast system of the type described herein that is devoid of fossil fuel tanks and a fossil fuel engine. Fossil fuel tanks and engines typically consume a significant amount of volume on a vessel, making it difficult to include a battery-ballast system of sufficient size to provide meaningful ballast adjustments. According to a further example, a watercraft is provided that includes a hull, a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, an air storage tank in selective fluid communication with the air motor, an air compressor operable to selectively supply compressed air to the air storage tank, and ballast including a plurality of batteries, the batteries of which are selectively positionable along at least one of a longitudinal axis of the vessel and a transverse axis of the vessel. In one embodiment of a further example, the watercraft is devoid of fossil fuel and a fossil fuel engine. According to the same or other examples, the watercraft includes a potable water system, for example, a potable water system 340 of the type shown in FIGS. 6A and 6B .

[0066] Referring to FIG. 7, an air and electric propulsion system 40 useful for use with a watercraft including a battery ballast system of the type described herein is provided. The air and electric propulsion system of FIG. 7 is sized for a small watercraft, such as the watercraft 10 of FIG. 1. However, the size and / or number of components may be increased as needed depending on the size and weight of the watercraft. With reference to the watercraft 10 of FIG. 1 and the air and electric propulsion system 40 of FIG. 7, a watercraft including an air and electric propulsion system and a battery ballast system is described. However, it should be understood that the watercraft 10 and the air and electric propulsion system 40 can be appropriately sized to accommodate the battery ballast system 211 of the watercraft 200, and that the watercraft 200 having the air and electric propulsion system 40 of FIG. 7 with a battery ballast system of the type described herein is expressly intended to be appropriately sized to accommodate the dimensions of the watercraft 200.

[0067] The propeller 52a is operatively connected to the proximal propeller shaft section 48a, which rotates about its longitudinal axis 1 to rotate the propeller 52a through the body of water. Rotation of the propeller 52a through the water propels the watercraft 10 in a direction defined by the direction of rotation of the propeller 52a, the shape of the propeller blades, and the orientation of the rudder 32.

[0068] In this embodiment, the watercraft 10 is not powered by a fossil fuel engine and does not include a fossil fuel engine or fossil fuel tank. Instead, an air motor is provided that operates to rotate at least one propeller. Referring to FIG. 7 , an air propulsion system 40 is provided that includes a propeller train 42, an air supply system 47, and a rechargeable battery system 44. A control system is also provided. The air supply system 47 includes at least one compressed air storage tank in selective fluid communication with the at least one air motor, and at least one compressor operable to selectively supply compressed air to the at least one air storage tank.

[0069] In FIG. 7, the at least one propeller used to propel the watercraft 10 through water includes two propellers 52a, 52b. The propeller train 42 includes two parallel propeller systems 43a, 43b. Each propeller system 43a, 43b further includes a respective propeller shaft assembly 46a, 46b and a respective propeller 52a, 52b. The propeller shaft assembly 46a is a multi-segment shaft including a proximal propeller shaft section 48a and a distal propeller shaft section 50a. The proximal propeller shaft section 48a and the distal propeller shaft section 50b are connected by a coupler 54a. The proximal end of the propeller shaft assembly 46a is defined by the proximal end of the proximal propeller shaft section 48a and is connected to an air motor 62a. The distal end of propeller shaft assembly 46a is defined by the distal end of distal propeller shaft section 50a and is coupled to propeller 52a. Similarly, propeller shaft assembly 46b is a multi-segment shaft including proximal propeller shaft section 48b and distal propeller shaft section 50b. Proximal propeller shaft section 48b and distal propeller shaft section 50b are connected by coupler 54b. The proximal end of propeller shaft assembly 46b is defined by the proximal end of proximal propeller shaft section 48b and is coupled to air motor 62b. The distal end of propeller shaft assembly 46b is defined by the distal end of distal section 50b and is coupled to propeller 52b. Each propeller shaft assembly 46a, 46b has a length along longitudinal axis l. When each air motor 62a, 62b is activated, each shaft assembly 46a, 46b rotates about its respective longitudinal axis 1, as indicated by the curved arrow. The rotation of the shafts causes each propeller 52a, 52b to rotate about its longitudinal axis 1, moving the watercraft 10 through the water.

[0070] As described above, the air motors 62a, 62b are operable to rotate the respective propeller shaft assemblies 46a, 46b and respective propellers 52a, 52b. The air motors take in compressed air and expand it to produce mechanical work. The air motors may be linear or rotary, depending on the type of mechanical work required. For the air motors 62a, 62b, rotary air motors are preferred. The specific rotational frequency and horsepower of the propellers depend on the weight and desired speed of travel of the watercraft 10. In one example, a rotary air motor is used. Suitable commercially available rotary air motors include the 1UP-NRV-15 rotary air motor from Gast Manufacturing, Inc. of Benton Harbor, Michigan. This motor provides 0.45 HP and 5.25 in-lb of torque at a maximum (no-load) rotational speed of 6000 RPM. It also provides a maximum torque of 6.0 in-lb at 500 RPM. The motor's maximum air consumption is 27 cubic feet per minute. The shaft diameter is 3 / 8 inch and the intake port size is 1 / 8 inch NPT. The maximum pressure rating is 80 psig. For a Marine 200, a suitable air motor would have at least 29-30 HP and approximately 65 lb-ft at a maximum speed of approximately 1400 rpm. f It includes an Ingersoll Rand KK5B piston air motor that provides 1.5-ft of torque. The motor's maximum air consumption is approximately 800-850 standard cubic feet per minute.

[0071] The air used to operate the air motors 62a, 62b is provided by an air supply system 47. The air supply system 47 includes an air compressor 78 and multiple in-line air storage tanks 80a, 82a, 80b, 82b. The term "in-line" refers to the fact that each pair of storage tanks (80a / 82a and 80b / 82b) is in the flow path from the compressor 78 to the air motors 62a, 62b. The pair of storage tanks, 80a / 82a on the one hand and 80b / 82b on the other hand, are parallel to each other but are each in the flow path from the compressor discharge lines (108a, 108b, respectively) to the air motors 62a, 62b. In other words, the air storage tanks 80a, 82a, 80b, 82b do not supply the air motors 62a, 62b in parallel with the compressor 78. One or more auxiliary air compressors (not shown) may be provided to supply auxiliary air to ensure that the air motors 62a, 62b have sufficient air flow while also ensuring that the air storage tanks 80a, 82a, 80b, 82b can be refilled after reaching a desired depletion condition (e.g., a pressure condition below a threshold).

[0072] The air compressor 78 discharges to and is in fluid communication with parallel slave air storage tanks 82a, 82b via compressor discharge lines 108a, 108b. Each slave air storage tank 82a, 82b is fluidly connected to and in fluid communication with a respective master air storage tank 80a, 80b by a respective pressure reduction valve 84a, 84b. The pressure reduction valves 84a, 84b ensure that the slave air storage tanks 82a, 82b operate at a higher pressure than their corresponding master air storage tanks 80a, 80b, ensuring that air flows from the slave air storage tanks 82a, 82b to their corresponding master air storage tanks 80a, 80b, but not back out of the air storage tanks 80a, 80b, such as when the slave air storage tanks 82a, 82b are being refilled. The extra pressure drop causes the compressor 78 to operate at a higher discharge pressure and lower flow rate than would otherwise be required, preventing excessive air supply to the air motors 62a, 62b. The pressure drop valves 84a, 84b may be control valves, pressure regulators, check valves, etc. However, in certain instances, they are not automatically operable to achieve the desired pressure; rather, they simply provide a source of pressure drop within the system to regulate compressor operation to the higher discharge pressure regime. In certain embodiments, the pressure drop across each pressure drop valve is from about 1000 psig to about 4000 psig, preferably from about 1500 psig to about 3500 psig, even more preferably from about 2000 psig to about 3000 psig, and even more preferably from about 2400 psig to about 2600 psig.

[0073] In a preferred embodiment, the air compressor 78 periodically operates to fill the slave air storage tanks 82a, 82b until their respective pressures reach a desired maximum pressure (Pmax). Filling the slave air storage tanks 82a, 82b also fills the master air storage tanks 80a, 80b with air. This periodic refilling operation occurs when the pressure in the slave air storage tanks 82a, 82b reaches a predetermined lower limit (Pmin). Low-pressure switches may be attached to the slave air storage tanks 82a, 82b to determine when the predetermined lower limit pressure Pmin has been reached. Alternatively, hardware or firmware within the control unit 69 may use a pressure signal provided by a pressure sensor in the slave air storage tanks 82a, 82b to determine when the pressure drops below Pmin. Among other benefits, periodic (not continuous) operation of the compressor 78 allows the watercraft 10 to operate quieter for extended periods of time (e.g., when the compressor is off). In certain examples, Pmin is greater than or equal to about 1500 psig, preferably greater than or equal to about 1700 psig, and more preferably greater than or equal to about 1900 psig. In the same or other embodiments, Pmin is less than or equal to about 2500 psig, preferably greater than or equal to about 2200 psig, and more preferably greater than or equal to about 2100 psig.

[0074] The inline slave air storage tanks 82a, 82b are preferably maintained at an operating pressure above a first specified threshold, a predetermined lower limit (Pmin), and below a second specified threshold, a predetermined upper limit (Pmax). The predetermined lower limit Pmin is preferably high enough to maintain the desired air flow rate to the air motors 62a, 62b at the desired air inlet pressure at the air motors 62a, 62b. The rotary air motors 62a, 62b have characteristic curves relating motor rotational speed to air motor inlet pressure and volumetric air flow. The inline air storage tanks 80a / 80b, 82a / 82b ensure that the desired combination of volumetric air flow rate and air motor inlet pressure is maintained to achieve the desired propeller rotational speed. Additionally, the tanks 80a / 80b, 82a / 82b are preferably pre-charged to the desired maximum tank pressure (Pmax) prior to departure. As a result, the compressor 78 need only operate periodically. However, when the compressor 78 is operating, it is preferable for the compressor discharge flow rate (mass of air) to exceed the rate of consumption by the air motors 62a, 62b so that the tanks 80a, 80b, 82a, 82b are refilled. Nevertheless, even during refilling operations, the air motors 62a, 62b may periodically consume more air than the compressor 78 supplies, so long as they consume less air on average than is supplied by the compressor 78. Thus, the in-line air storage tanks 80a, 80b, 82a, 82b may allow greater flexibility in regulating the boat's speed by providing surge and reserve volumes of air.

[0075] In one example, the desired maximum air pressure Pmax for the slave tanks 82a, 82b is at least about 3000 psig, preferably at least about 4000 psig, and more preferably at least about 4200 psig. Pmax is preferably no greater than about 6000 psig, preferably no greater than about 5000 psig, and more preferably no greater than about 4600 psig. In the same or other embodiments, the volume of each slave tank 82a, 82b and master tank 80a, 80b is at least about 350 cubic feet, preferably at least about 380 cubic feet, and more preferably at least about 440 cubic feet, and the volume is no greater than about 530 cubic feet, preferably no greater than about 500 cubic feet, and more preferably no greater than about 450 cubic feet. One exemplary type of air storage tank useful as the master tanks 80a, 80b and slave tanks 82a, 82b is the NUVT4500 storage tank supplied by Nuvair of Oxnard, California. The tanks have a maximum working pressure of 4500 psig and an internal storage volume of 437 cubic feet. In one embodiment where the watercraft is a vessel 200, the volume of each slave tank 82a, 82b and master tank 80a, 80b is sized to provide a desired maximum vessel speed at the maximum anticipated vessel weight based on the vessel weight, the selected air motor, the anticipated maximum cargo load, and non-cargo items that affect the vessel weight.

[0076] The air compressor 78 draws air from the atmosphere and compresses it to a pressure sufficient to supply the master and slave tanks 80a / 80b, 82a / 82b until the slave air storage tanks 82a, 82b reach their desired maximum pressure (Pmax) during the filling operation. A high-pressure switch may be provided to determine when Pmax is reached. The switch may be a hardware switch installed on each slave air storage tank 82a, 82b, or a software or firmware switch in a controller within the power distribution board 88 that receives a pressure sensor signal from a sensor located on the slave air storage tanks 82a, 82b. In either configuration, the controller uses the input signal or signals to determine whether to turn off the compressor 78 motor. In the case of multiple slave air storage tanks 82a, 82b, the compressor 78 can be turned off when either of the slave tanks 82a, 82b reaches Pmax. Alternatively, the compressor 78 may remain on until both slave air storage tanks 82a, 82b reach Pmax. However, the former approach is preferred because it prevents overfilling of the slave air storage tanks 82a, 82b if one of the pressure sensors or switches fails. Suitable commercially available air compressors include the Bauer Model No. 100 air compressor, which has a maximum air discharge pressure of approximately 5000 psig. For the vessel 200, a suitable air compressor is preferably selected based on the desired maximum motor power.

[0077] The compressor 78 discharges compressed air to the slave air storage tank 82a via compressor discharge line 108a and to the slave tank 82b via compressor discharge line 108b. In some embodiments, the air compressor 78 can supply air at a mass flow rate that exceeds the rate at which the air motors 62a, 62b consume air at their maximum operating speed and desired maximum compressor discharge pressure. In this case, the rate at which compressed air is added to the slave air storage tanks 82a, 82b by the compressor 78 exceeds the rate at which air is consumed by the air motors 62a, 62b, such that when the slave air storage tanks 82a, 82b are filling (when their pressures reach the desired low pressure limit P), the amount of air in the master tanks 80a / 80b and slave tanks 82a / 82b increases until the pressure in the slave air storage tanks 82a, 82b reads the desired upper pressure limit P.

[0078] The slave air storage tanks 82a, 82b are maintained at a pressure that varies between a first selected value (a predetermined minimum pressure (Pmin)) and a second selected value (a predetermined maximum pressure (Pmax)). When air is flowing to the air motors 62a, 62b, the pressure in the master air storage tanks 80a, 80b will be lower than the pressure in the slave air storage tanks 82a, 82b. The air pressure in the slave tanks 82a, 82b and the master tanks 80a, 80b will be significantly higher than required by the air motors 62a, 62b. This is because it is desirable to maximize the amount of air pre-charged into the slave tanks 82a / 82b and master tanks 80a / 80b while controlling the air flow to the air motors 62a, 62b so that the speed of the watercraft 10 can be controlled. In order to regulate the air flow to the air motors 62a, 62b, the pressure must be significantly reduced from the pressure in the storage tanks 80a / 80b, 82a / 82b. In a first example, pressure drop valves 84a, 84b significantly reduce the air pressure. However, in addition, pressure regulators 86a, 86b (fixed or adjustable valves that reduce air pressure) are provided downstream of master air storage tanks 80a, 80b. Master air storage tank discharge line 110a is connected to regulator 86a, and master air storage tank discharge line 110b is connected to regulator 86b. Regulators 86a, 86b control the inlet air pressure to air pressure control unit 69. In one example, regulators 86a, 86b control the inlet pressure of control unit 69 to about 80 psig to about 120 psig, preferably about 90 to about 110 psig, and more preferably about 95 to about 105 psig. In one particular example, 100 psig is used.

[0079] The air pressure control unit 69 includes compressed air discharge lines 68, 70. Air pressure supplied to the air motors 62a, 62b via the discharge lines 68, 70 is adjustable using a throttle 72. The compressed air discharge line 68 is a forward line preferably connected in parallel to the air motor forward inlet port 64a of the air motor 62a and the air motor forward inlet port 64b of the air motor 62b. The compressed air discharge line 70 is a reverse line preferably connected in parallel to the air motor reverse inlet ports 66a, 66b of the air motor 62b. One or more internal air control valves within the control unit 69 adjust the air pressure in the discharge lines 68, 70 based on the position of the throttle 72. The throttle 72 includes two levers that can be operated to selectively supply air from the forward line 70 or the reverse line 68 to move the watercraft 10 forward and reverse (i.e., the throttle 72 is operable to adjust the air flow rate and the direction of propeller rotation). Supplying air to the air motor forward injection ports 64a, 64b rotates the gears within the air motors 62a, 62b in a first direction, which causes the propellers 52a, 52b to rotate in a first direction about the longitudinal axis 1 of the propeller shaft, moving the watercraft 10 forward. Supplying air to the air motor reverse injection ports 66a, 66b rotates the gears within the air motors 62a, 62b in a second direction, which causes the propellers 52a, 52b to rotate in a second direction about the longitudinal axis 1 of the propeller shaft, moving the watercraft 10 backward. The lever of the throttle 72 is operable to rotate the propellers 52a, 52b in both forward and reverse directions from zero speed to the maximum rotational speed of the air motors 62a, 62b. In one embodiment, the supply pressure to the air motors 62a, 62b ranges from 0 to 100 psig, corresponding to a propeller speed of 0 to about 400 rpm.

[0080] The throttle 72 includes wires 98a, 98b and / or appropriate electronics that send control signals to the control unit 69, causing the control unit 69 to adjust the controller discharge pressure in lines 68, 70 via an internal air control valve. Thus, the master air storage tanks 80a, 80b are in fluid communication with the air motors 62a, 62b via pressure regulators 86a, 86b and air control valves within the control unit 69. In certain embodiments, the compressed air pressure in the compressed air discharge lines 68, 70 ranges from 0 to approximately 100 psig.

[0081] The control unit 69 is also operably connected to indicators 74, 76. The indicators 74, 76 provide a visual indication of the rotational speed (e.g., RPM) of each propeller 52a, 52b based on appropriate gauges connected to the propeller shaft assemblies 46a, 46b or air motors 62a, 62b. Indicator lines 100a, 100b provide the electrical signals necessary to operate the indicators 74, 76 and to provide electrical communication with other devices used to indicate the rotational speed of the air motors 62a, 62b or shaft assemblies 46a, 46b.

[0082] The air compressor 78 (and auxiliary compressor, if provided) is preferably powered by battery power. A plurality of batteries 92a, 92b, 94a, 94b are provided to supply the electrical energy necessary to operate the air compressor 78. The positive terminals of batteries 92a, 94a are connected to a power distribution board 88 via electrical connections 102a, 102b, respectively, and the negative terminals of batteries 92a, 94a are connected to earth. The positive terminals of batteries 92b, 94b are connected to the power distribution board 88 via electrical connections 103a, 103b, and the negative terminals of batteries 92b, 94b are connected to earth. The power distribution board 88 is connected to the positive terminal of the electric motor of the air compressor 78 via connection 113a and to the negative terminal of the electric motor of the air compressor 78 via connection 113b. The power distribution board 88 selects one of the four batteries 92 a , 94 a , 92 b , 94 b at a time to power the compressor 78 .

[0083] Batteries 92a, 94a, 92b, 94b are preferably rechargeable and each is capable of providing the energy necessary to periodically operate compressor 78. Suitable examples include lithium iron phosphate batteries. Batteries 92a, 94a, 92b, 94b are preferably selected to provide a voltage compatible with the requirements of motor compressor 78 and sufficient capacity to ensure sufficient power to enable watercraft 10 to remain at sea at a desired speed for a desired period of time without recharging. In one example, batteries 92a, 94a, 92b, 94b are supplied by RELi, Inc. of Fort Mill, South Carolina. 3 Four sizes of 8D lithium iron phosphate batteries supplied by ON® are used. The batteries 92a, 94a, 92b, and 94b are connected to a recharging panel 90 via recharging lines 104a, 104b, 106a, and 106b. The recharging panel 90 is connected to a plug 96 that connects the recharging panel 90 to a dock power source. When the watercraft 10 is docked in port, the plug 96 can be connected to a power source to recharge the batteries 92a, 94a, 92b, and 94b. As previously mentioned, 512 batteries are shown for the vessel 200. The particular size, weight, and energy capacity of the batteries may be selected based on the weight of the vessel 200, the expected cargo load, the desired maximum draft, the expected power load for operating the vessel's electrical systems, and the expected variations in list and trim that the battery ballast system 211 is expected to encounter. An exemplary mass of an individual battery 292 is at least 40 lb. m , at least 60 lbs m , and at least 80 lbs m and simultaneously contains a mass of 200 lb m Below, 175 lb. m and below 150 lb m It contains the following masses:

[0084] In a particular example, the kinetic energy of the rotating propeller shaft assemblies 46a, 46b is converted into electrical energy for use by other electrical systems onboard the watercraft 10. In one embodiment, an alternator 58a, 58b, 60a, 60b is connected to each shaft assembly 46a, 46b to convert a portion of the kinetic energy of the rotating shafts into electrical energy. The current provided by the alternators 58a, 58b, 60a, 60b is provided to a power distribution board 88. The power distribution board 88 can then provide current to recharge accessory batteries used to operate lights, horns, radios, etc.

[0085] In some embodiments, the propulsion system 40 is used to retrofit a watercraft 10 from which an existing fossil fuel engine and fossil fuel tanks have been removed. In certain embodiments, the components forming the propulsion system 40 are significantly lighter than the removed fossil fuel tanks and engine, fossil fuel, and engine, while still allowing the watercraft 10 to remain at sea longer than a watercraft 10 equipped with a fossil fuel engine and fuel tanks. In certain examples, additional batteries, such as batteries 92a, 94a, 92b, and 94b, can be installed and used as both ballast and additional power sources to allow the watercraft 10 to remain at sea even longer. In such cases, each battery 92a, 94a, 92b, and 94b is preferably selectively positionable along one or both of the vessel's longitudinal axis and the vessel's transverse axis.

[0086] In a preferred embodiment, multiple batteries 92a, 94a, 92b, 94b are provided, each functioning as one of the ballast batteries 292 of FIGS. 3A-3B and 4-5. In one embodiment, each battery 92a, 94a, 92b, 94b is a standard truck battery. In a preferred embodiment, the ballast system 211 is designed to selectively electrically connect any number of batteries 92a, 94a, 92b, 94b to a power grid operatively connected to the power distribution board 88 and the compressor 78 and any powered components, allowing any combination of batteries 92a, 94a, 92b, 94b to be used. In such a case, a carriage assembly, such as carriage assemblies 214-244, is provided and designed with conductive paths so that when a given slot is occupied by a battery 92a, 94a, 92b, 94b, that battery can be selectively connected to the power grid and the power distribution board 88 to power accessories or devices requiring battery power.

[0087] The following describes how the watercraft 10 is operated. The watercraft 10 is docked. The compressed air storage tanks 80a / 80b, 82a / 82b are filled with air until the slave air storage tanks 82a, 82b reach their desired maximum pressure, Pmax. The air motors 62a, 62b are initially off, so the master tanks 80a, 80b are at the same pressure as their respective slave tanks 82a, 82b. For NUVT4500 tanks, the maximum pressure is the working pressure of 4500 psig. At this point, the pressure regulators 86a, 86b are set to supply the desired air pressure (e.g., 100 psig) to the supply lines 112a, 112b of the control unit 69. However, the internal valves of the control unit 69 are closed, providing no air (e.g., 0 psig) to the air motors 62a, 62b. The batteries 92a, 94a, 92b, 94b are fully charged. After the watercraft 10 is undocked, the throttle 72 is actuated to transmit air pressure to the air motor forward injection ports 64a, 64b via the forward line 68, with the throttle position corresponding to both the pressure in the forward line 70 and the RPM of the propellers 52a, 52b. The batteries 92a, 92b, 94a, 94b are aligned along the longitudinal and spanwise axes of the watercraft 10 to provide the desired trim and heel at launch. Additionally, the freshwater tank 346 preferably contains a volume of water that, when combined with the weight of the batteries and carriage assembly, provides the initial desired amount of total ballast.

[0088] After a period of voyage operation, the air pressure in the slave air storage tanks 82a, 82b drops to a first selected value, the desired minimum pressure Pmin. At this point, the controller in the power distribution panel 88 electrically connects one of the batteries 92a, 94a, 92b, 94b to the electric motor driving the compressor 78 and / or activates the electric motor that operates the compressor 78. The compressor 78 takes in ambient air, compresses it, and channels it to the slave air storage tanks 82a, 82b and then to the master air storage tanks 80a, 80b. Alternatively, the regulators 86a, 86b can be configured and / or controlled to use only one pair of tanks 80a / 82a or 80b / 82b at a time. When the pressure in the slave air storage tanks 82a, 82b reaches a second selected value, the desired maximum pressure Pmax, the compressor 78 is turned off (e.g., by removing power from the power distribution panel 88). If the slave air storage tanks 82a, 82b are at different pressures, the system may be configured to turn off the compressor 78 when either of the slave tanks 82a, 82b reaches a desired maximum pressure Pmax. The system may be configured to keep the compressor 78 running until both slave tanks 82a, 82b reach Pmax, but it is preferable to turn off the compressor 78 when one of the pressure sensors or switches reaches Pmax to prevent overfilling in case one of them fails.

[0089] This process of turning compressor 78 on and off is repeated as pressure drops and rises within slave tanks 82a, 82b. Eventually, the currently active one of batteries 92a, 94a, 92b, 94b drops to a low enough potential difference with the controller in switchboard 88 to place another one of batteries 92a, 94a, 92b, 94b in electrical communication with the motor of compressor 78. Furthermore, the entire process consumes no fossil fuels and produces no emissions of carbon dioxide, carbon monoxide, water, NOx, SOx, or other pollutants.

[0090] If it is desired to adjust the trim of the watercraft 10, one or more of the batteries 92a, 92b, 94a, 94b can be moved along the longitudinal axis of the watercraft 10. If it is desired to adjust the heel of the watercraft 10, one or more of the batteries 92a, 92b, 94a, 94b can be moved along the transverse axis of the watercraft 10. In instances where the watercraft 10 is a larger vessel, such as the watercraft 200, additional batteries may be provided in the manner described above for the ballast battery 292 in FIGS. 3A-3B, 4, and 5. If the overall draft of the watercraft 10 needs to be reduced, potable water may be discharged overboard via the overboard line 411 using the ballast controller 400 or any of the other techniques described above. Conversely, if more draft is needed, the flow of seawater to the potable water treatment system 340 may be increased by increasing the setting of the flow controller 353 or using any of the other techniques described above to increase the level in the tank 346.

[0091] Example 1 A 1972 Luhrs sport fishing boat weighing approximately 19,000 pounds is provided. The boat includes two Chrysler 318cc engines. Including reverse and reduction gears, the engines weigh approximately 900 pounds each. Two 75-gallon gasoline tanks are also included, for a total empty weight of approximately 250 pounds. 150 gallons of gasoline weighs approximately 1,100 pounds. Therefore, the total weight of the gasoline engines, gasoline tanks, and gasoline is approximately 3,150 pounds. The boat is modified to be propulsion system 40 of FIG. 2.

[0092] The Chrysler engine, gas tanks, and gas are removed from the vessel. The vessel is equipped with four Nuvair NUVT4500 compressed air storage tanks, each weighing approximately 145.5 pounds empty.

[0093] Two GAST 1UP-NRV-15 rotary air motors are arranged as shown in FIG. 2. One commercially available main compressor weighing approximately 800 pounds and two commercially available auxiliary compressors weighing approximately 400 pounds are also arranged. The compressors have a maximum discharge pressure of approximately 4500 psig and are selected to provide a flow rate in excess of the amount of air consumed by the air motors 62a, 62b, or to supply air to both air tanks 80a, 82a, 80b, 82b, when the watercraft 10 is at a cruising speed of 15 to 18 miles per hour. Each air motor 62a, 62b weighs approximately 25 pounds. RELi 3 Twelve ON® Lithium Iron Phosphate 12V batteries, size 8D, weighing 83 lbs, were installed. The boat had its existing control panel and electrical panel, which were rewired and equipped with pneumatic lines for use with the air motor.

[0094] The modified components are approximately 220 pounds heavier than the removed components. However, before the modification, the watercraft 10 consumes approximately 7 gallons of gasoline per hour when traveling at a speed of 15 to 18 miles per hour, depleting the 150-gallon fuel supply in approximately 21.4 hours. In contrast, twelve lithium iron phosphate batteries are estimated to be able to operate the main and auxiliary compressors continuously for 72 hours, even if the compressors only operate periodically during operation (i.e., the pressure in the slave tanks 82a, 82b drops below Pmin). Using twelve lithium iron phosphate batteries of the type described above, the air motor can operate continuously for approximately 36 days (874 hours), even with the main and auxiliary compressors operating continuously, allowing the watercraft 10 to move through the water at speeds of approximately 15 to 18 miles per hour. Thus, the air propulsion system according to the present disclosure provides the ability to remain at sea more than 30 times longer than a fossil fuel engine and fuel system for a vessel of the same size.

[0095] When only one of the twelve lithium iron phosphate batteries is used, the watercraft 10 can remain at sea more than three times longer using the air propulsion system of the present disclosure than the fossil fuel system it replaced, and the modified watercraft 10 weighs over 650 pounds less than the original watercraft. Thus, it has been surprisingly discovered that an air propulsion system constructed in accordance with the present disclosure not only avoids the burning of fossil fuels, but also allows the vessel to remain at sea much longer than a fossil fuel engine.

[0096] It has been discovered that adding lithium iron phosphate batteries also aids in maintaining the heel and trim of the watercraft 10. According to this embodiment, the lithium iron phosphate batteries are selectively positionable along the longitudinal and transverse axes of the boat, preferably using a carriage system similar in design and size to the ballast system 211 of FIGS. 3A-3B, 4, and 5. When the watercraft 10 exhibits positive stern trim (FIG. 1), one or more of the twelve lithium iron phosphate batteries are moved toward the bow along the boat's longitudinal axis to reduce stern trim. Conversely, when the watercraft 10 exhibits negative stern trim, one or more lithium ion batteries are moved toward the stern along the longitudinal axis to increase stern trim.

[0097] 2B, when the heel angle is a positive angle in the clockwise direction when looking at the stern of the watercraft 10 in a direction toward the bow of the watercraft 10, one or more of the lithium iron phosphate batteries are moved along the spanwise axis toward the port side of the watercraft 10. Conversely, when looking at the stern of the watercraft 10 in a direction toward the bow of the watercraft 10, when the watercraft 10 has a negative heel angle in the clockwise direction, one or more of the lithium iron phosphate batteries are moved along the spanwise axis of the watercraft 10 toward starboard.

[0098] Example 2 An example of a large ship with a 112-foot beam equipped with a battery ballast system such as battery ballast system 211 of Figures 3A-3B is provided herein. One hundred carriage assemblies similar to carriage assemblies 214-244 are provided and positioned on lower deck 210. Each carriage assembly has eight tiers arranged along the ship's height axis H. Each battery support (e.g., battery support 271) on each carriage assembly is four feet long along the ship's length axis, two feet wide along the ship's width axis, and spaced two feet apart from its vertically adjacent neighbors. 100 feet of the ship's 112-foot width are available for carriage assemblies. Thus, there are 100 / 2 = 50 slots (e.g., H(1)-H(50)) with each tier of each carriage assembly. Each tier has 32 batteries and battery supports, occupying 32 of the 50 slots. Each battery weighs 150 pounds, and the average weight per slot (taking into account that 18 slots do not have battery supports 271) is 20 pounds. Therefore, the battery weight per stage on each carriage support is 150 pounds x 32 batteries / stage = 49,800 pounds / stage. The slot weight per stage (excluding batteries) is 20 pounds / slot x 50 slots / stage = 1,000 pounds / stage. Therefore, the weight of each stage, including batteries, is 50,800 pounds, or 25.4 tons.

[0099] Each carriage assembly has eight stages, so the total weight per carriage assembly is 8 stages / carriage assembly (25.4 tons / stage) = 203.2 tons / carriage assembly. The total weight of the entire battery ballast system is 100 carriage assemblies x 203.2 tons / carriage assembly = 20,320 tons. A potable water system is provided and includes a fresh water tank 200 feet long and 50 feet by 14 feet in cross section, in the shape of a rectangular parallelepiped, providing a volume of 145,600 cubic feet. The weight of potable water in such a tank is 145,600 cubic feet x 62.4 pounds / cubic foot = 4,542 tons.

[0100] In one embodiment, the potable water tanks are designed to provide ballast water capacity in excess of the amount required to meet the maximum anticipated potable water consumption on board the ship. As previously mentioned, battery ballast can be used to adjust the ship's list and trim, but batteries cannot be selectively added or removed from the ship while at sea. In one embodiment, the potable water tanks are sized to hold the maximum required amount of potable water needed for consumption on board the ship over a specified period of time and to ensure that the ship's waterline does not change more than a desired amount as the cargo load varies between the expected minimum and maximum loads. Based on the known relationship between the ship's gravity (i.e., weight expressed as a force), the buoyancy exerted by the water body, and the maximum desired variation in the waterline, a maximum allowable change in the ship's weight is calculated. This variation corresponds to the weight and volume of ballast water held in the potable water tanks and the maximum change in cargo weight. If the ship is desired to handle larger variations in cargo weight while remaining within the desired maximum variation in the waterline, additional potable water tank capacity may be provided so that the weight of potable water allocated to ballast is adjusted accordingly. For example, if a ship's maximum waterline variation is 20 feet, we can calculate the corresponding change in the ship's total weight corresponding to that waterline variation. The maximum weight variation can be assigned as follows: (7)ΔM T =ΔM C +ΔM B where ΔM T = Total change in hull weight (lb) corresponding to the maximum permissible change in waterline height m or kg) ΔM C = Maximum expected fluctuation in cargo weight (lb) m or kg) ΔM B = Maximum variation in ballast mass (lb m or kg)

[0101] The mass of the battery ballast does not change at sea, so ΔM Bcan be used to calculate the increment of potable water required for the largest desired cargo and equation (3) above can be used to calculate the waterline variation.

[0102] The present invention has been described with reference to specific exemplary embodiments thereof. However, it will be readily apparent to those skilled in the art that the present invention can be embodied in specific forms other than the exemplary embodiments described above. This can be done without departing from the spirit of the invention. The exemplary embodiments are merely illustrative and should not be considered limiting in any way. The scope of the present invention is defined by the appended claims and their equivalents, rather than the foregoing description. According to aspect (1), there is provided a watercraft, The hull and a propeller operable to propel the watercraft through a body of water; an air motor operable to rotate the propeller; an air storage tank in selective fluid communication with the air motor; an air compressor operable to selectively supply compressed air to said air storage tank; ballast including a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along at least one of a longitudinal axis of the vessel and a transverse axis of the vessel; It is a watercraft equipped with According to aspect (2), the batteries of the plurality of batteries are selectively positionable relative to the hull along the longitudinal axis of the vessel and the transverse axis of the vessel. According to aspect (3), there is provided a battery ballast system comprising a carriage system and the plurality of batteries, wherein the carriage system includes a plurality of carriage assemblies, each of the carriage assemblies including a plurality of steps, each of the steps including a pair of tracks, and the carriage system further includes a plurality of battery supports, each of which engages with a corresponding one of the pair of tracks and is movable along the corresponding one of the pair of tracks. According to aspect (4), the watercraft has a deck, and the battery ballast system is disposed below the deck along the axis in the height direction of the vessel. According to aspect (5), the deck is a lower deck, and the watercraft further includes a main deck above the lower deck along the height direction of the ship. According to aspect (6), the battery support is movable along the axis in the width direction of the ship relative to the hull. According to aspect (7), the carriage assembly is movable along the longitudinal axis of the vessel relative to the hull. According to aspect (8), the watercraft has a bow and a stern, and at least some of the carriage assemblies are movable along the longitudinal axis of the vessel from a first position near the bow to a second position near the stern. According to aspect (9), each stage has a set of the batteries including the plurality of batteries, and at least some of the batteries in at least one stage are movable from a first position near the port side of the ship to a second position near the starboard side of the ship. According to aspect (10), each of the stages includes a plurality of slots sized to accommodate the battery supports, and less than half of the slots in each of the stages are occupied by the battery supports. According to aspect (11), each of the batteries of the plurality of batteries is selectively electrically connected to a power grid of the watercraft. According to aspect (12), the watercraft has a deadweight tonnage, and the plurality of batteries have a total weight that is approximately 20% to 30% of the deadweight tonnage of the watercraft. According to aspect (13), the drinking water system further includes a condenser, an evaporator, an untreated water inlet, and a treated water tank. According to aspect (14), the vessel further includes a control system operably connected to the carriage system and each of the battery supports and operable to adjust the position of each of the carriage assemblies along the longitudinal axis of the vessel and the position of each of the battery supports along the transverse axis of the vessel. According to aspect (15), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (16), the watercraft does not include a ballast water tank that is not fluidly connected to a potable water supply system. According to an aspect (17), there is provided a watercraft, The hull and a propeller operable to propel the watercraft through a body of water; an air motor operable to rotate the propeller; an air compressor operable to selectively supply compressed air to the air motor, the watercraft not including a fossil fuel engine or fossil fuel tank; ballast including a plurality of batteries, the batteries of the plurality of batteries being selectively positionable along at least one of a longitudinal axis of the vessel and a transverse axis of the vessel; It is a watercraft equipped with According to aspect (18), a battery ballast system is provided comprising a carriage system and the plurality of batteries, wherein the carriage system includes a plurality of carriage assemblies, each of the carriage assemblies including a plurality of steps, each of the steps including a pair of tracks, and the carriage system further includes a plurality of battery supports, each of the battery supports engaging with a corresponding one of the pair of tracks and movable along the corresponding one of the pair of tracks. According to aspect (19), the carriage assembly is movable along the longitudinal axis of the vessel relative to the hull. According to aspect (20), the battery support is movable along the axis in the width direction of the ship relative to the hull. According to aspect (21), the watercraft has a bow and a stern, and at least a portion of the carriage assembly is movable along the longitudinal axis of the vessel from a first position between the bow and a mid-ship position along the longitudinal axis of the vessel to a second position between the stern and the mid-ship position along the longitudinal axis of the vessel. According to aspect (22), each of the stages has a set of the batteries, and at least some of the batteries in at least one stage are movable from a first position between the port side of the ship and a mid-ship position along the transverse axis of the ship to a second position between the starboard side of the ship and the mid-ship position along the transverse axis of the ship. According to aspect (23), each of the stages includes a plurality of slots sized to accommodate battery supports, with less than half of the slots in each of the stages being occupied by the battery supports. According to aspect (24), each of the batteries of the plurality of batteries is selectively electrically connected to a watercraft power grid. According to aspect (25), the watercraft has a deadweight tonnage, and the batteries have a total weight that is approximately 20% to 30% of the deadweight tonnage of the watercraft. According to aspect (26), the system further includes a drinking water system including a condenser, an evaporator, an untreated water inlet, and a treated water tank. According to aspect (27), the vessel further includes a control system operably connected to the carriage system and each of the battery supports and operable to adjust the position of each of the carriage assemblies along the longitudinal axis of the vessel and the position of each of the battery supports along the transverse axis of the vessel. According to aspect (28), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (29), the watercraft does not include a ballast water tank that is not fluidly connected to a potable water supply system. According to a thirty aspect, there is provided a watercraft, comprising: The hull and a propeller operable to propel the watercraft through a body of water; a battery ballast system comprising a carriage system and a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along a longitudinal axis and a transverse axis of the vessel; It is a watercraft equipped with According to aspect (31), the carriage system includes a plurality of carriage assemblies, each of the carriage assemblies including a plurality of steps, each of the steps including a pair of tracks, and the carriage system further includes a plurality of battery supports, each of which engages with a corresponding one of the pair of tracks and is movable along the corresponding one of the pair of tracks. According to aspect (32), the battery support is movable along the axis in the width direction of the ship relative to the hull. According to aspect (33), the carriage assembly is movable along the longitudinal axis of the vessel relative to the hull. According to aspect (34), the watercraft has a bow and a stern, and the carriage assembly is movable along a longitudinal axis of the vessel from a first position near the bow to a position near the stern. According to aspect (35), each stage has a set of the batteries including the plurality of batteries, and the set of the batteries is movable from a first position near the port side of the ship to a second position near the starboard side of the ship. According to aspect (36), each of the stages includes a plurality of slots sized to receive the battery supports, and less than half of the slots in each of the stages are occupied by the battery supports. According to aspect (37), each of the batteries of the plurality of batteries is electrically connected to a power grid of the watercraft. According to aspect (38), the watercraft has a deadweight tonnage and the batteries have a total weight that is approximately 20% to 30% of the deadweight tonnage of the watercraft. According to aspect (39), the system further comprises a drinking water system including a condenser, an evaporator, an untreated water inlet, and a treated water tank. According to aspect (40), there is further provided a control system operably connected to the carriage system and each of the battery supports and operable to adjust the position of each of the carriage assemblies along the longitudinal axis of the vessel and the position of each of the battery supports along the transverse axis of the vessel. According to aspect (41), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (42), the watercraft does not include a ballast water tank that is not fluidly connected to a potable water supply line. According to aspect (43), there is provided a method of adjusting trim for a watercraft having a hull and having bow and stern defining a longitudinal axis, the method comprising: providing a battery ballast system comprising a carriage system and a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along a longitudinal axis and a transverse axis of the vessel; selectively moving a subset of the plurality of batteries along the longitudinal axis relative to the hull; The method includes: According to aspect (44), the carriage system includes a plurality of carriage assemblies, each carriage assembly selectively movable along the longitudinal axis, each carriage assembly including a plurality of steps, each step including a pair of tracks, the carriage system further including a plurality of battery supports, each battery support engaging with a corresponding one of the pair of tracks and movable along the corresponding one of the pair of tracks; Each battery of the plurality of batteries is disposed on one of the battery supports of the plurality of battery supports, and selectively moving a subset of the plurality of batteries along the longitudinal axis includes selectively moving a subset of the carriage assemblies along the longitudinal axis. According to aspect (45), a watercraft includes a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, an air storage tank in selective fluid communication with the air motor, and an air compressor operable to selectively supply compressed air to the air storage tank. According to aspect (46), the method includes selectively energizing the air compressor with at least one of the plurality of batteries. According to aspect (47), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (48), the watercraft does not include a ballast water tank that is not fluidly connected to a potable water system. According to aspect (49), selectively moving the subset of the plurality of batteries along the longitudinal axis includes collectively moving the subset of the plurality of batteries from a first position near the bow to a second position near the stern. According to aspect (50), a method of adjusting heel of a watercraft having a hull and having port and starboard sides defining a spanwise axis, comprising: providing a battery ballast system comprising a plurality of batteries and a plurality of stages, each stage comprising a plurality of battery supports movable relative to the hull along the transverse axis; selectively moving a subset of the plurality of batteries along the transverse axis relative to the hull; The method includes: According to aspect (51), each of the stages includes a pair of tracks, each of the battery supports engages with a corresponding one of the pair of tracks and is movable along the corresponding one of the pair of tracks, and selectively moving a subset of the plurality of batteries along the widthwise axis includes selectively moving the battery support corresponding to the battery of the subset of the plurality of batteries along the pair of tracks corresponding to the battery support. According to aspect (52), the battery ballast system includes a carriage system including a plurality of carriage assemblies, each of the carriage assemblies including a subset of the stages of the plurality of stages. According to aspect (53), a watercraft includes a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, an air storage tank in selective fluid communication with the air motor, and an air compressor operable to selectively supply compressed air to the air storage tank. According to aspect (54), the method includes selectively energizing the air compressor with at least one of the plurality of batteries. According to aspect (55), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (56), the watercraft does not include a ballast water tank that is not fluidly connected to a potable water system. According to aspect (57), selectively moving a subset of the plurality of batteries along the widthwise axis includes selectively moving the subset of the plurality of batteries from a first position near the port side to a second position near the starboard side. According to aspect (58), there is provided a method for adjusting a draft of a watercraft, the watercraft including a potable water system having an untreated water inlet in fluid communication with a desalination unit and a fresh water tank in fluid communication with the desalination unit, the method including adjusting a volume of fresh water in the fresh water tank. According to aspect (59), adjusting the volume of fresh water in the fresh water tank includes discharging a corresponding volume of water overboard. According to aspect (60), adjusting the volume of fresh water in the fresh water tank includes adjusting the flow rate of untreated water to the drinking water system. According to aspect (61), the watercraft includes bow and stern defining a longitudinal axis, port and starboard sides defining a transverse axis, a hull, and a battery ballast system including a plurality of batteries selectively positionable relative to the hull along the longitudinal axis and the transverse axis, and the method includes moving a subset of the batteries along the longitudinal axes. According to aspect (62), the battery ballast system further includes a carriage system, the carriage system including a plurality of carriage assemblies, each of the carriage assemblies including a plurality of stages, each of the stages including a pair of tracks and a corresponding plurality of battery supports, the plurality of battery supports movably engaging with the pair of tracks corresponding to the plurality of battery supports. According to aspect (63), the watercraft has a bow and a stern, and each carriage assembly is movable relative to the hull along a longitudinal axis from a first position near the bow to a second position near the stern. According to embodiment (64), the desalination device includes a condenser and an evaporator. According to aspect (65), the watercraft includes a propeller operable to propel the watercraft through a body of water, an air motor operable to rotate the propeller, an air storage tank in selective fluid communication with the air motor, and an air compressor operable to selectively supply compressed air to the air storage tank. According to aspect (66), the watercraft does not include a fossil fuel engine or a fossil fuel tank. According to aspect (67), the method includes selectively energizing an air compressor with at least one battery of the plurality of batteries. According to aspect (68), the watercraft does not include a ballast water tank that is not fluidly connected to any type of potable water system.

Claims

1. A watercraft, The hull and a propeller operable to propel the watercraft through a body of water; a battery ballast system comprising a carriage system and a plurality of batteries, the batteries of the plurality of batteries being selectively positionable relative to the hull along a longitudinal axis and a transverse axis of the vessel; Equipped with the carriage system includes a plurality of carriage assemblies, each of the carriage assemblies including a plurality of steps, each of the steps including a pair of tracks; the carriage system further includes a plurality of battery supports, each of the battery supports engaging a corresponding one of the pair of tracks and movable along the corresponding one of the pair of tracks; Each of the battery supports is independently movable along a transverse axis of the vessel relative to the hull. Watercraft.

2. 2. The watercraft of claim 1, wherein the battery support is movable relative to the hull along a transverse axis of the vessel.

3. 3. A watercraft according to claim 1 or claim 2, wherein the carriage assembly is movable relative to the hull along the transverse axis of the vessel.

4. 4. The watercraft of claim 1, wherein the watercraft has a bow and a stern, and the carriage assembly is movable along the longitudinal axis of the vessel from a first position near the bow to a position near the stern.

5. 5. The watercraft of claim 1, wherein each stage has a set of the batteries including the plurality of batteries, the set of batteries being movable from a first position near the port side of the vessel to a second position near the starboard side of the vessel.

6. 6. A watercraft according to any one of claims 1 to 5, wherein each of the stages includes a plurality of slots sized to receive the battery supports, and wherein less than half of the slots in each of the stages are occupied by the battery supports.

7. 7. The watercraft of claim 1, wherein each battery of the plurality of batteries is electrically connected to a watercraft electrical grid.

8. 8. The watercraft of claim 1, wherein the watercraft has a deadweight tonnage and the batteries have a total weight that is approximately 20% to 30% of the deadweight tonnage of the watercraft.

9. 9. The watercraft of claim 1, further comprising a potable water system including a condenser, an evaporator, an untreated water inlet, and a treated water tank.

10. 7. A watercraft as claimed in any one of claims 1 to 6, further comprising a control system operably connected to the carriage system and each battery support and operable to adjust the position of each carriage assembly along the longitudinal axis of the vessel and the position of each battery support along the transverse axis of the vessel.

11. 11. A watercraft according to any one of claims 1 to 10, wherein the watercraft does not include a ballast water tank that is not fluidly connected to a potable water supply line.

12. 1. A method of adjusting trim for a watercraft having a hull and having bow and stern defining a longitudinal axis, comprising: providing a battery ballast system comprising a plurality of batteries and a carriage system including a plurality of carriage assemblies capable of accommodating the plurality of batteries, wherein the carriage assemblies within the plurality of carriage assemblies are individually movable along the longitudinal axis of the vessel relative to the hull to selectively position the plurality of batteries along the hull; selectively moving a subset of the plurality of batteries along the longitudinal axis relative to the hull; A method comprising:

13. The method of claim 12 , wherein the watercraft does not include ballast water tanks that are not fluidly connected to a potable water system.

14. 1. A method of adjusting heel of a watercraft having a hull and having port and starboard sides defining a spanwise axis, comprising: providing a battery ballast system comprising a plurality of batteries and a plurality of stages, each stage comprising a plurality of battery supports independently movable relative to the hull along the transverse axis; selectively moving a subset of the plurality of batteries along the transverse axis relative to the hull; A method comprising:

15. 15. The method of claim 14, wherein the watercraft does not include ballast water tanks that are not fluidly connected to a potable water system.

Images