Vessel with improved stability curve

Abstract

The invention relates to a vessel (1) having motorised propulsion means (8, 9), with a streamlined hull (2), having an improved stability curve and including at least one keel (3a, 3b) and at least one bulbous bow (4), the vessel (1) being a wave piercer and being configured to sail at speeds corresponding to a Froude number greater than 0.45 without, however, being of the planing type, wherein the hull (2) has specific dimensions. The vessel (1) has a stability curve such that the righting arm GZ reaches a maximum value (GZMax) for a heel angle of the vessel greater than 90° and is less than 0.1 metre (GZ10) when the heel angle of the vessel is 10 degrees.

Description

[0001] Title: Vessel with improved stability curve.

[0002] Field of invention

[0003] The field of the invention relates to shipbuilding. The invention relates more particularly to a vessel having an improved stability curve and exhibiting advantageous performance in its use as a drone, in particular in hydrographic measurement and surveillance missions, in particular due to its improved stability.

[0004] State of the art

[0005] Marine drones, particularly surface ship drones, are increasingly used for various missions: hydrography, particularly of the deep seabed, laying cables or pipelines, surveillance, inspection, maintenance and repair, particularly of wind farms, underwater positioning, etc.

[0006] Since these drones are unmanned and the means for their maintenance / repair are generally remote, it is necessary that they are reliable and efficient and that they can withstand and operate in potentially violent navigation conditions.

[0007] It is therefore necessary for these vessels to have very good stability, both for the quality of the measurements and the results of their missions, and for their durability, these two qualities being able to be antagonistic. Indeed, they must be very stable to ensure their survival in very rough seas but a high initial stability implies a very high sensitivity to waves (especially beam) because this stability implies strong accelerations in rolling, and angular accelerations are very detrimental to the quality of the measurements.

[0008] We know from patent application FR3065705 filed in the name of IXBLUE a “Surface vessel with motorized propulsion with a fusiform hull and ballasted keel” which exhibits good behavior in rough seas thanks to its shape.

[0009] The invention provides a vessel with improved stability which is particularly efficient and stable and which has significant autonomy.

[0010] Summary of the invention

[0011] More specifically, the invention relates to a motor-powered surface vessel, comprising a spindle-shaped hull and at least one ballasted keel in the lower part of the hull, the hull being elongated in a longitudinal direction of the vessel and comprising a live work part and a dead work part separated by a waterline, said at least one keel being provided at its lower end with at least one bulb internally providing a storage space for instrumentation and comprising ballast, said at least one bulb having a length in the longitudinal direction of the hull of between 3 and 10 meters, the vessel being of the wave-piercing type and configured to navigate at speeds corresponding to a Froude number greater than 0.45 without being of the "planing" type, the hull having a shape having:

[0012] - a total width to total length ratio of less than 0.15,

[0013] - a total length of less than 20 meters,

[0014] - a total length of at least 8 meters,

[0015] - a ratio of the freeboard height to the hull height of between 0.1 and 2, the hull height being the height measured between the fully loaded waterline of the vessel and the lowest point of the hull, excluding the keel and other appendages, said vessel having a stability curve representing variations of a righting lever arm GZ of the vessel as a function of angles of heel of the vessel, the righting lever arm GZ being defined between a centre of gravity (G) of the vessel and a centre of flotation (B) of the vessel where the sum of the flotation forces of the vessel is applied.

[0016] According to the invention, the righting lever arm GZ of the stability curve of the ship in navigation conditions, both empty and fully loaded and in both cases without any deck loading: reaches a maximum (GZMax) for a ship heel angle greater than 90° and

[0017] - is less than 0.1 meter (GZ10) when the ship's heel angle is 10 degrees, the maximum (GZMax) of the righting lever arm being the maximum of the lever arm (GZ) of the ship's stability curve.

[0018] Other advantageous characteristics of the vessel according to the invention, taken individually or in all technically possible combinations, are the following:

[0019] - the ship has no wind propulsion system,

[0020] - the ship is a drone,

[0021] - motorized propulsion includes mechanical propulsion powered by an internal combustion engine,

[0022] - motorized propulsion includes electric propulsion powered by an electric motor,

[0023] - the vessel has several separate keels aligned longitudinally under the vessel, each keel having its own bulb or adjacent keels having a bulb in common extending between said adjacent keels,

[0024] - the vessel has two separate keels aligned longitudinally under the vessel, both keels having a bulb in common,

[0025] - the vessel also includes at least one submerged appendage chosen from appendages such as rudder, fins, anti-drift planes outside the keel, wing or stabilizing flap, - the vessel includes at least two mobile submerged appendages including at least one rudder and one stabilizing flap,

[0026] - the vessel has a housing for equipment at the rear, said housing being located above the waterline of the hull,

[0027] - the equipment housing has an opening on the transom of the vessel allowing the said equipment to be launched,

[0028] - the hull is made up of several sections which are assembled together and which are removable and interchangeable,

[0029] - the hull has an interchangeable rear section,

[0030] - the vessel is primarily propelled by a motorized propulsion system comprising at least one engine driving a submerged terminal thrust device,

[0031] - the submerged thrust terminal device is a propeller,

[0032] - the submerged thrust terminal device is a turbine,

[0033] - the hull has an interchangeable rear section with motorized propulsion systems.

[0034] - motorized propulsion systems are at least one electric motor,

[0035] - motorized propulsion systems are at least one internal combustion engine,

[0036] - the interchangeable rear section includes the equipment housing,

[0037] - the hull has an interchangeable front section,

[0038] - the hull has an intermediate section with a kiosk erected upwards, above the waterline

[0039] - the bulb or at least one of the bulbs includes acoustic transducers,

[0040] - acoustic transducers are sonar,

[0041] - at least one of said at least one keel is removable,

[0042] - the vessel has at least one retractable keel in vertical translation in the kiosk,

[0043] - the hull comprises an intermediate section comprising a kiosk erected upwards above the waterline, and a removable keel, preferably retractable by raising it through the hull and inserting it into the kiosk,

[0044] - the hull and main deck are made of “E” fiberglass composite, i.e. “E-glass”, and epoxy by infusion on a polyvinyl chloride body,

[0045] - the kiosk is made of “E” fiberglass composite, i.e. “E-glass”, and epoxy by infusion on a polyvinyl chloride body,

[0046] - the pins are made of “E” fiberglass composite, i.e. “E-glass”, and epoxy by infusion on a polyvinyl chloride body,

[0047] - the bulb(s) are made of “E” fiberglass composite, i.e. “E-glass”, and epoxy by infusion on a polyvinyl chloride body, - as an alternative or in addition to fiberglass, carbon and / or aramid fibers are used,

[0048] - the submerged appendages are made of “E” fiberglass composite, i.e. “E-glass”, and epoxy by infusion on a polyvinyl chloride body,

[0049] - at least one bulb of said at least one bulb is interchangeable,

[0050] - the vessel has at least one interchangeable bulb,

[0051] - the bulb or at least one of the bulbs has an internal space allowing the installation of at least four payloads,

[0052] - the geometry of the bulb is designed so that the bulb produces hydrodynamic lift along a vertical axis and in a positive direction, i.e. upwards, when the ship moves forward,

[0053] - the ship has a bulb which is configured to produce hydrodynamic lift along a vertical axis and in a positive direction, i.e. upwards, when the ship moves forward.

[0054] Brief description of the figures

[0055] In the attached figures:

[0056] [Fig. 1] represents a side / lateral view of an example of a vessel according to the invention, said vessel being a drone,

[0057] [Fig. 2] represents the ship of figure 1 in a semi-rear and slightly plunging perspective view,

[0058] [Fig. 3] represents the vessel of figure 1 in a semi-rear and slightly plunging perspective view which carries in the equipment accommodation housing of the rear part of the hull a catamaran structure with payload, said structure being navigable and capable of being dropped and recovered,

[0059] [Fig. 4] represents the vessel of figure 1 in a semi-rear and slightly plunging perspective view which carries in the equipment housing of the rear part of the hull a system for dropping and recovering a payload comprising a winch, a cable and a sliding and articulated ramp, the payload of the autonomous or wire-guided underwater vehicle type being stored in the sliding and articulated ramp,

[0060] [Fig. 5] [Fig. 6] [Fig. 7] [Fig. 8] represent the release by launching the autonomous or wire-guided underwater vehicle from the ship of Fig. 4, the underwater vehicle being autonomous or being wire-guided and then remaining connected by the umbilical cable to the ship,

[0061] [Fig. 9] represents the vessel of figure 1 in a semi-rear and slightly plunging perspective view which carries in the housing of the rear part of the hull a system for releasing and recovering a payload comprising a winch, a cable and a sliding and articulated ramp, the payload of the autonomous robotic towed vehicle (ROTV) type being stored in the sliding and articulated ramp, [Fig. 10] represents the release by launching the autonomous robotic towed vehicle (ROTV) from the vessel of figure 9, the robotic towed vehicle (ROTV) is then towed while submerged,

[0062] [Fig. 11] represents a ship in cross-section diagrammatically showing GZ, the ship's righting lever arm, the ship's center of gravity G and the ship's center of flotation, Bo being the ship's center of flotation without heel and Bi being the ship's center of flotation with heel, and

[0063] [Fig. 12] represents two curves of GZ as a function of the heel angle for two different vessels but configured according to the invention,

[0064] [Fig. 13] represents an enlargement of the curves of figure 14 around the origin of the GZ (GZ=0) and the angles (0°),

[0065] [Fig. 14] represents a comparison between GZ curves as a function of the ship's heel angle for different ships referenced ab and cdeghi by their GZ curves,

[0066] [Fig. 15] is a wireframe perspective view of the vessel of the invention,

[0067] [Fig. 16] is a wireframe side view of the vessel of the invention,

[0068] [Fig. 17] is a wire-frame top view of the vessel of the invention,

[0069] [Fig. 18] is a wire front view of the vessel of the invention, and

[0070] [Fig. 19] shows views of the ships referenced cdeghi serving as comparison for figures 13 and 14.

[0071] Detailed description

[0072] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0073] We first recall the following definitions:

[0074] - the transom is the emerged part of the rear / stern of the ship's hull,

[0075] - the freeboard height (Hfb in the figures) of the vessel is the height between the waterline (Lf in the figures) when the vessel is fully loaded and the main deck (the edge is referenced 25 in the figures),

[0076] - the hull is the submerged part of the hull excluding appendages, therefore excluding propulsion units and keel(s) and bulb(s), and, within the framework of the invention, the hull height (HdeC figure 16) is the height measured vertically between the waterline (Lf in the figures) when the vessel is fully loaded and the lowest point of the hull, excluding appendages, therefore excluding propulsion units and keel(s) and bulb(s),

[0077] - deck cargo refers to all the goods stowed on deck, - GZ is defined as the ship's righting lever arm, and is the projected distance between the ship's center of gravity G and the ship's center of flotation (B), the center of flotation B being the point where the sum of the ship's buoyancy forces is applied. In Figure 11, Bo is the center of flotation of the ship without a list, GZ=0 in this case, and Bi is the center of flotation of the ship with a list (GZ<>0), and

[0078] - GZMSX is the maximum of the GZ evolution curve as a function of the ship's heel angle a.

[0079] In Figure 11 of a hull in cross section, 30 is the horizontal with respect to which the indicated heel angle a is determined (a on the right in Figure 11). The heel angle a is also defined by the intersection of the longitudinal plane of symmetry of the hull (passing through Bo and G) and the vertical passing through Z and Bi (a at the top of Figure 11).

[0080] As an example, two curves a (for the ship "Drix Ocean"), b (for the ship "Drix EM712"), of GZ as a function of the ship's heel angle are shown in Figure 12. These two curves a, b correspond to different ships, one of which is described in more detail below, and which are both configured according to the invention. For these two ships, the GZ curves are above 0° at all ship's heel angles, i.e. between 0 and 180 degrees. It is noted that the GZ at low angles is very low, which is a sign of insensitivity to beam waves. In addition, the GZ passes through a maximum for ship's heel angles greater than 90°, which is a sign of very high resistance to extreme sea conditions. Such characteristics are not found in conventional ships, in particular drones.

[0081] Figures 13 and 14 allow a comparison of the GZ curves as a function of the ship's heel angle between the ships "Drix Ocean" (curve a) and "Drix EM712" (curve b) and other ships:

[0082] “iXWork50”, 15-meter long cargo ship (curve c),

[0083] “Cmm”, 25-meter cargo vessel (curve d), “iXWork40 WF”, 12-meter speedboat (curve e), “Workboat_Sample”, 20-meter cargo vessel (curve g), “30m Crew Supply Vessel”, 30-meter personnel transfer vessel (curve h) and

[0084] “Rigidlnflatable”, 8 meter semi-rigid (i curve).

[0085] Views of the cdeghi referenced vessels corresponding to the cdeghi curves are visible in figure 19.

[0086] For the "Drix Ocean", the hull height HdeC is approximately 1.2 meters and the freeboard height Hfb is approximately 1 meter. These values ​​vary depending on the weight of the ship's cargo. In the example ship 1 shown in Figures 1 to 10 and 15 to 18, two keels 3a, 3b are used, these two keels 3a, 3b sharing a single bulb 4.

[0087] Vessel 1 has a hull 2 ​​of the wave-piercing type and is configured to sail at speeds corresponding to a Froude number greater than 0.45 without being of the "planing" type. Hull 2 ​​has a total length of approximately 15.5 meters, a maximum width of approximately 1.75 meters and a total height of its submerged parts, i.e. hull and also appendages, propulsion units, keels and bulb of approximately 2.5 meters.

[0088] The hull 2, in its hull part, comprises submerged propulsion members: a steerable propulsion unit 8 which is arranged under the rear part 6 of the hull which corresponds to the rear section 21 of the latter, a fixed propulsion unit 9 with a transmission shaft and which is arranged towards the rear part of the hull, between the two keels 3a, 3b.

[0089] The hull 2 ​​has internal storage compartments and in its rear part 6 has a housing 12 for receiving external equipment, for storing / transporting equipment. The housing 12 for receiving equipment is on the upper side of the hull 2 ​​forming the main deck of the ship.

[0090] Stabilizing wings (i.e. fixed position device) or flaps (i.e. adjustable device) 11 are arranged on either side of the front part of the bulb 4.

[0091] The keels 3a, 3b also include movable vertical elements 7 of the rudder or fin type.

[0092] Note that in the context of the invention, the bulb is considered equivalent to a gondola, the bulb having a shape flattening towards the rear and more rounded towards the front where a sonar and / or sounder is installed for a sonar scan oriented forward and downward. In particular, in Figures 15 and 18 the visible front part of the bulb / gondola has a cross shape in a circle which corresponds to the sonar and / or sounder 24.

[0093] It should also be noted that the shape and arrangement of the bulb allow hydrodynamic lift to be produced along a vertical axis and in a positive direction, i.e. upwards, when the vessel is moving forward. The vertical thrust axis due to the bulb is located in the longitudinal axial plane and can be positioned longitudinally vertical to the center of gravity, in which case the lift of the appendage will reduce the sinking of the advancing hull. The longitudinal position of the thrust can also be positioned either in front of or behind the center of gravity, in which case the action of this lift will also have an impact on the longitudinal trim of the vessel moving forward. This lift is the consequence of the asymmetry of the upper and lower shapes of the bulb / gondola. Thus, by playing on the shapes of the bulb, it is possible to act on the amount of lift as well as on the center of thrust of this lift. A bow thruster 10 (ietransverse thruster) is arranged towards the front of hull 2 ​​of ship 1 in the hull part of hull 2.

[0094] In the part above the waterline of the hull, i.e. above the waterline and in practice on the main deck, a kiosk 5 is erected in the approximately middle part of the hull, in the intermediate section 22, i.e. between the forward part / forward section 23 and the aft part 6 corresponding to the aft section 21 of the hull. The kiosk comprises one or more of the following equipment or parts of equipment (e.g. antennas, sensors, transducers, etc.): telecommunications (e.g. WIFI, 4G, Satellite, Broadband radio, SSB radio, VHF radio, VHF over IP / INTERNET protocol, etc.), radar, lidar, camera(s) (e.g. infrared, visible, color, black and white, etc.), automatic identification system (AIS - class A), directional acoustic antenna, etc.

[0095] Still in the above-water part of the hull, access hatches to the storage compartments are arranged. The storage compartments allow the storage of equipment or parts of equipment including those listed above. Moreover, the kiosk 5 may also include one or more access hatches to one or more storage compartments of its own. At least one of the storage compartments may be a temperature-controlled enclosure, a cold generating unit, i.e. air conditioning, being on board the vessel.

[0096] Other hatches may also be provided on the above-water part of the hull or in the kiosk for access to the internal organs of the ship, including energy sources, e.g. electrical (e.g. batteries), mechanical (e.g. internal combustion engine, in particular diesel, which can also possibly produce electrical energy), thermal (e.g. cold or heat generator), hydraulic (e.g. pump), pneumatic (e.g. compressor), chemical (e.g. fuel tank, possibly oxidizer), transmission organs (e.g. the intra-hull part of the propeller shaft), internal wiring of the ship, in particular electrical and data transmission (e.g. computer bus, optical fiber), internal circuitry of the ship, in particular pipes (e.g. fuel system), connections (e.g. access hatch to a fuel filler neck, electrical connector for recharging batteries, etc.)), control and navigation equipment (e.g. a computer system, in particular for pre-programmed and / or remote-controlled mission management, obstacle avoidance system, route planning, corridor navigation mode, path tracking mode, autonomous underwater vehicle (AUV) or wire-guided vehicle tracking mode, destination indication navigation mode, etc.).

[0097] Finally, in the rear part 6 of the hull 2, the housing 12 for receiving equipment is located above the waterline of the hull and is therefore completely or mostly out of the water (e.g. the rear end of the housing 12 may be partly in the water).

[0098] This housing is similar to a cradle or cockpit for receiving (storing or transporting) equipment 13, 14; 16, 17, 18 or 19. It forms a recess in the main deck of the ship and has a front edge at the front and two side edges laterally. The edges being erected upwards, they are therefore raised relative to the bottom (i.e. floor) of the equipment housing. The rear of the equipment housing 12 is open on the transom 20 of the hull and forms a U-shaped notch therein. The equipment housing 12 is therefore open upwards and aft. The opening on the transom 20 of the stern of the ship allows the equipment received in the housing to be launched into the water.

[0099] The equipment, eg 13, 14; 16, 17, 18; 19, which is stored / transported in this housing 12 of the ship 1 can be made directly integral (in a removable manner for some) with the bottom and / or the walls of the housing, that is to say that each of the elements of the equipment in the case where the equipment is not made up of a single element, must be installed individually.

[0100] However, when the equipment is made up of several elements it is advantageous to provide a support or cradle for fixing the elements and it is this support or cradle which is installed and made integral with the equipment housing. Thus, it is possible to have a stock of several supports or cradles having different equipment pre-installed, the support or cradle therefore being pre-equipped, and to install the support or cradle useful for the intended mission in the housing: it is then sufficient to only fix the pre-equipped support or cradle in the ship's housing without having to install each element of the equipment on the ship. The exchange of equipment is therefore greatly simplified.

[0101] The support can be a simple flat plate and the cradle a U-shaped plate in cross section which fits the shape of the material housing.

[0102] The empty weight of the ship 1 is approximately 9 metric tons and in addition to the carrying capacity of the bulb 4, the equipment accommodation 12 of the aft part 6 of the hull 2 ​​of the ship 1 has a carrying capacity of approximately 1 metric ton.

[0103] Due to its dimensions, the ship 1 can be transported in a standard container. In addition, the case of a ship whose bulb(s) and / or keel(s) are removable, i.e., dismountable, retractable or retractable as appropriate, is provided. It is also provided that the ship's kiosk 5 and / or the aerial appendages it may contain, e.g., antenna, radar, etc., are removable, i.e., dismountable, retractable or retractable as appropriate.

[0104] The maximum speed of Vessel 1 is approximately 16 knots (1 knot = 1.852 kilometers / hour). The average operating speed of Vessel 1 is between 0 and 16 knots, with electric propulsion allowing for very low speed movement.

[0105] The vessel uses a hybrid diesel and electric engine. The vessel 1 has a 110 kW diesel engine capable of achieving a maximum speed of approximately 16 knots with the propeller 9 and drive shaft. It is also possible to use a more powerful 300 kW diesel engine. The vessel 1 also has a 20 kW electric auxiliary propeller 8. A more powerful electric auxiliary propeller can be used. The vessel has rechargeable batteries with a total capacity of between 20 and 30 kWh. The batteries can be recharged by an electric generator (dynamo or alternator) of the diesel engine and / or by connection to an electrical source external to the vessel. In an advantageous embodiment, the electric thruster can operate as an electric generator, in particular for recharging the batteries.

[0106] Finally, in order to ensure the regulation of the temperature of the ship's compartment(s), a cold generating unit, i.e. air conditioning, is implemented.

[0107] The diesel tank, which can be in several sub-tanks distributed within hull 2, has a capacity of approximately 2,300 liters.

[0108] Typically, ship 1 has a range of 2500 nautical miles (1 nautical mile = 1,852 km) at a speed of 8 knots.

[0109] Figures 3, 4-8 and 9, 10 show several examples of equipment that can be stored / transported in this equipment housing 12 of the ship 1.

[0110] Figure 3, the equipment installed in the equipment housing 12 is a catamaran structure 13 with two side floats 15 which is configured to carry a payload 14. The catamaran structure 13 is preferably seaworthy and can be dropped and recovered on the vessel. The catamaran structure 13 can drop and recover the payload 14 which is here a torpedo-shaped autonomous exploration device.

[0111] In one variant, the catamaran structure 13 remains fixed in position in the accommodation (apart from equipment exchanges), the payload 14 being able to be dropped and recovered.

[0112] It should be noted that the catamaran structure 13 installed in the equipment housing 12, due to the presence of its two lateral floats 15, can, in the event that the two lateral floats 15 of the catamaran structure 13 are in contact with the water, provide additional stability to the vessel 1.

[0113] The two lateral floats 15 can therefore comprise propulsion and guidance / maneuverability devices, in particular when the catamaran structure 13 is navigable. Furthermore, with the propulsion and guidance / maneuverability devices of the two lateral floats 15 and if the two lateral floats 15 are in contact with the water with the catamaran structure 13 installed in the housing 12 then the latter can provide additional propulsion and maneuverability to the vessel 1.

[0114] Figures 4-8, the equipment installed in the equipment housing 12 is a payload release and recovery system which is of the autonomous underwater vehicle type 18. The release and recovery system comprises a winch 16, a cable and a sliding and articulated ramp 17, the autonomous underwater vehicle being stored in the sliding and articulated ramp 17.

[0115] The sliding and articulated ramp 17 can slide out of the housing, towards the rear of the ship, then tilt to form a guide for launching the autonomous underwater vehicle 18, as shown in Figures 5 to 8, and vice versa for its recovery. The sliding and articulated ramp 17 remains secured to the ship 1 and does not move away from it. In this example, the autonomous underwater vehicle 18, which can move away from the ship 1, remains connected by the cable to the ship 1.

[0116] Figures 9-10, the equipment installed in the equipment housing 12 is still a system for dropping and recovering a payload but this time it is of the robotic towed vehicle (ROTV) type 19. The dropping and recovery system comprises, as before, a winch 16, a cable and a sliding and articulated ramp 17, the robotic towed vehicle (ROTV) 19 being stored in the sliding and articulated ramp 17.

[0117] The operation of the drop and recovery system is similar to the previous one. However, unlike the autonomous underwater vehicle 18.

[0118] It is envisaged within the framework of the implementation of the invention that other types of equipment are installed in the housing 12 and in particular equipment which does not require launching to accomplish a mission. Thus, an aerial drone can take off and land directly from the housing 12.

[0119] It is understood that the vessel of the invention may be implemented differently, for example with one keel or more than two keels, with more than one bulb, without flap 11 or more flaps than in the example.

Claims

CLAIMS 1. Motor-powered surface vessel, comprising a fusiform hull (2) and at least one keel (3a, 3b) ballasted in the lower part of the hull, the hull (2) being elongated in a longitudinal direction of the vessel and comprising a live work part and a dead work part separated by a waterline (Lf), said at least one keel (3a, 3b) being provided at its lower end with at least one bulb (4) internally providing a storage space for instrumentation and comprising ballast, said at least one bulb (4) having a length in the longitudinal direction of the hull of between 3 and 10 meters, the vessel being of the wave-piercing type and configured to navigate at speeds corresponding to a Froude number greater than 0.45 without being of the "planing" type, the hull (2) having a shape having: - a total width to total length ratio of less than 0.15, - a total length of less than 20 meters, - a total length of at least 8 meters, - a ratio of the freeboard height (Hfb) to the hull height (HdeC) between 0.1 and 2, the hull height (HdeC) being the height measured between the waterline (Lf) at full load of the vessel and the lowest point of the hull, excluding the keel and other appendages, said vessel having a stability curve representing variations of a righting lever arm GZ of the vessel as a function of angles of heel of the vessel, the righting lever arm GZ being defined between a centre of gravity (G) of the vessel and a centre of flotation (B) of the vessel where the sum of the buoyancy forces of the vessel is applied, in which, the righting lever arm GZ of the stability curve of the vessel in navigation condition, both empty and fully loaded and in both cases without any deck loading: - reaches a maximum (GZMax) for a ship's heel angle greater than 90° and - is less than 0.1 meter (GZ10) when the ship's heel angle is 10 degrees, the maximum (GZMax) of the righting lever arm being the maximum of the lever arm (GZ) of the ship's stability curve.

2. A vessel according to claim 1, comprising a plurality of distinct keels (3a, 3b) aligned longitudinally beneath the vessel, each keel having its own bulb (4) or adjacent keels having a bulb in common extending between said adjacent keels.

3. Vessel according to claim 2, comprising two separate keels (3a, 3b) aligned longitudinally under the vessel, the two keels having a bulb (4) in common.

4. Vessel according to any one of claims 1 to 3, comprising in the rear part (6) a housing (12) for receiving equipment (13, 14; 16, 17, 18; 19), said housing being located above the waterline of the hull.

5. Vessel according to claim 4, in which the housing (12) for receiving equipment has an opening on the transom (20) of the vessel allowing said equipment to be launched.

6. Ship according to any one of claims 1 to 5, in which the hull (2) is made up of several sections (21, 22, 23) which are assembled together and which are removable and interchangeable.

7. Vessel according to claim 6, in which the hull comprises an interchangeable rear section (21) comprising motorized propulsion systems.

8. Vessel according to any one of claims 6 and 7, in which the hull (2) comprises an interchangeable front section (23).

9. Vessel according to any one of claims 6 to 8, in which the hull (2) comprises an intermediate section (22) comprising a kiosk (5) erected upwards, above the waterline.

10. Vessel according to claim 9, comprising at least one retractable keel in vertical translation in the kiosk (5).

11. Vessel according to one of claims 1 to 10, comprising at least one interchangeable bulb.

12. Vessel according to one of claims 1 to 11, mainly propelled by a motorized propulsion system (8, 9) comprising at least one motor driving a submerged terminal thrust device.

13. Vessel according to any one of claims 1 to 12, without a wind propulsion system.

14. Vessel according to one of claims 1 to 13, in which the bulb is configured to produce hydrodynamic lift along a vertical axis and in a positive direction, that is to say upwards, when the vessel moves forward.

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