Sail propulsion device for a ship

Abstract

The invention relates to a sail propulsion device using rotary sails, adaptable to a ship undergoing transformation / renovation and new construction, making it possible to reduce the consumption of said ship by around 50%. FIG. 4.

Description

Title of the invention: Sail propulsion device for a ship Technical field

[0001] The invention belongs to the field of marine propulsion, more particularly to the field of sail propulsion, as main propulsion or assistance.

[0002] The invention is adaptable to an existing ship or is integrated into the ship during its construction, or incrementally with the aim of reducing its consumption of fossil fuel. Prior art

[0003] 90% of world trade passes by ships, powered by fuels fossil fuels and which are responsible for around 3% of global greenhouse gas emissions.

[0004] About 7% of the world's oil, and thus used today to propel these ships.

[0005] International regulations aim to reduce CO2 emissions per tonne-kilometre by at least 40% in 2030, 70% in 2040 and close to 100% in 2050 compared to the 2008 reference year.

[0006] However, the total energy consumption of maritime transport, nearly 3000 TWh per year, is such that solutions based on low-carbon fuels such as agrofuels or synthetic fuels must be accompanied by measures to reduce the energy consumption of ships.

[0007] The use of sail propulsion is a solution that has been considered and is currently being developed, however it faces several difficulties.

[0008] First of all the tonnages, the ships concerned have loads several hundred times greater than the largest sailing ships built in the past.

[0009] Logistical constraints: ships must deliver their goods within predictable timescales which are difficult to adapt to the vagaries of the wind.

[0010] Also, the solutions adopted to date consist rather of using the means of sail propulsion as means of assistance to propulsion, the ship retaining motor means.

[0011] The sail propulsion systems deployed to date essentially include: "kites", rigid sails, deployable sails (conventionally or by inflation), thick suction profiles and Flettner rotors using the Magnus effect.

[0012] These systems make it possible to reduce the consumption of ships but also present technical and operational constraints: they require large surfaces to produce a propulsive force, they can require numerous masts which make port operations difficult, they can limit visibility, they can cause access difficulties in certain ports and navigation areas, due to the passage under bridges, they may require maintenance operations and replacement of parts subject to significant wear, and they do not provide gains for low apparent wind angles and in particular facing the wind. When they are not retractable or retractable, they can constitute significant additional aerodynamic drag and lead to additional consumption in these conditions, the vessel then being propelled by the engine.

[0013] Some systems such as Flettner rotors or thick suction profiles require energy to operate, under the majority of operating conditions, limiting their overall efficiency.

[0014] Thus, these prior art sail propulsion systems used on transport vessels of significant size, if they have a certain efficiency in favorable wind conditions (which can be obtained on certain maritime routes and / or by reducing the operating speed of the vessels), make it difficult to save more than 30% of the vessel's consumption while maintaining its operating speeds and on a variety of routes.

[0015] Summary of the invention

[0016] The invention aims to solve the drawbacks of the prior art, and aims to achieve a reduction in emissions greater than the devices of the prior art, in more extensive wind conditions and wider operation, and for this purpose relates to a ship comprising a displacement hull and motorized propulsion means, the ship producing hydrodynamic drag for a reference forward speed, comprising a sail propulsion device comprising a mast extending in a vertical direction, a rotor comprising a rotary wing capable of rotating about an axis of rotation secant to the vertical direction, the rotor being carried by the mast and comprising a device for orientation about the vertical direction, characterized in that the rotary wing is capable, when subjected to a wind, of producing a sail thrust to propel the ship and an engine torque about the axis of rotation.

[0017] Thus, this sail propulsion device for the ship is similar to a wind turbine, with the difference that the latter is used simultaneously and optimally to reduce the consumption of the ship to produce a steerable sail propulsion force to move the ship forward, while retaining the possibility of generating engine torque in order, in particular, to produce energy which can, in turn, be used for the propulsion of the ship or for other uses.

[0018] These characteristics allow this device to produce assistance to the propulsion, or even to produce all of the propulsion, in much more varied wind conditions than the systems of the prior art, in particular but not exclusively for low apparent wind angles and even facing the wind, while having a reduced size, at equivalent propulsion force, compared to the systems of the prior art.

[0019] The device obstructs visibility significantly less than prior art devices and its aerodynamic drag can be greatly reduced when the device is not in use.

[0020] The invention can be implemented according to the embodiments and variants set out below, which are to be considered individually or according to any technically effective combination.

[0021] According to an exemplary embodiment, a length of the hull is less than 150 meters, the reference forward speed is between 5 knots and 20 knots and the sail thrust, under a tailwind whose actual speed is equal to 2.5 times the reference forward speed, is equal to 50% or more of the hydrodynamic drag of the ship at said reference forward speed.

[0022] According to another embodiment, a length of the shell is greater than 150 metres, the reference forward speed is between 5 knots and 20 knots and the sail thrust, under a tailwind whose true speed is equal to 2.5 times the reference forward speed, is equal to 30% or more of the hydrodynamic drag of the vessel at said reference forward speed.

[0023] Advantageously, the sail propulsion device consists of two masts separated by a longitudinal distance.

[0024] Advantageously, the two masts are separated by a transverse gap.

[0025] According to an exemplary embodiment, the mast carries a single rotor whose rotating wing consists of two blades, one section of which is an aerodynamic wing profile, the rotor comprising a mechanism for orienting the blades around an axis relative to the rotor.

[0026] Advantageously, the ship comprises an electric battery and the sail propulsion device comprises an electric generator driven by the rotary sail.

[0027] According to one embodiment, the sail propulsion device comprises a nacelle connected to the mast and carrying the rotor, the electric generator being housed in the nacelle.

[0028] According to another embodiment, the electric generator is housed inside the mast or on a deck and is connected to the rotor by a mechanical or hydraulic connection capable of transmitting mechanical rotational power from the rotary wing to drive the electric generator.

[0029] Advantageously, the motorized propulsion means comprise means electric drives.

[0030] Advantageously, the electrical drive means are reversible and capable of producing electricity when they are driven.

[0031] Advantageously, the device comprises an electric motor capable of driving the rotary wing so as to operate the rotary wing as an aero-propulsor.

[0032] According to one embodiment, the sail propulsion device comprises a plurality of rotors distributed on the mast in the vertical direction.

[0033] Advantageously, the mast comprises a telescopic section.

[0034] According to a variant, the mast comprises a section tilting around a pivot with an axis perpendicular to the vertical direction.

[0035] Advantageously, a section of the mast is profiled so as to reduce aerodynamic drag of the mast.

[0036] This latter configuration also makes it possible to create additional sail thrust by using the mast as a rigid wing and orienting it judiciously according to the wind and navigation conditions. Brief description of the drawings

[0037] The invention is implemented according to the embodiments, which are in no way limiting and set out below with reference to [Fig.l] to [Fig.l4D] in which: Fig.l

[0038] [Fig.l] shows in a schematic sectional view a ship equipped with a sail propulsion device in a downwind navigation situation; Fig.2

[0039] [Fig.2] shows a schematic sectional view of a ship equipped with a sail propulsion device in a headwind navigation situation; Fig.3

[0040] [Fig.3] is an example of a flowchart representing a method of selecting a sail propulsion device for a ship; Fig.4

[0041] [Fig.4] shows in a profile view a cargo ship for an example of a sail propulsion device, with an enlarged view of a folded section of a blade profile of the sail propulsion device; Fig.5

[0042] [Fig.5] shows a side view of an oil tanker type vessel, equipped with a example of a sail propulsion device Fig.6

[0043] [Fig.6] is a schematic profile view in longitudinal section of an example of realization of a sail propulsion device in which an electric generator is placed inside the mast; Fig.7

[0044] [Fig.7] is a top view of the cargo ship of [Fig.4] in which the masts of the sail propulsion device are lowered on point; Fig.8

[0045] [Fig.8] is a front view schematic diagram showing the equivalence in terms of sail thrust of a single rotor and a plurality of rotors; Fig.9

[0046] [Fig.9] is an example of an embodiment, according to a front perspective view, of a sail propulsion device comprising multiple rotor masts; Fig. 10

[0047] [Fig.10] shows the ship of [Fig.9] with its masts retracted; Fig. ll

[0048] [Fig. 11] schematically shows the use of the power generated by the motorized propulsion device Fig. 12

[0049] [Fig.l2A], [Fig.l2B], [Fig.l2C], [Fig.l2D] and [Fig.l4D] schematically show in top view configurations of the sail propulsion device as a function of the wind direction; Fig. 13

[0050] [Fig.13] shows a top view of the ship of [Fig.4] with the rotors oriented relative to the longitudinal direction of the vessel; Fig. 14

[0051] [Fig.l4A], [Fig.l4B] and [Fig.l4C] schematically show in top view configurations of the sail propulsion device comprising 2 masts, depending on the wind direction. Description of the embodiments

[0052] Definitions

[0053] Ship means a vessel whose normal use consists of moving so as to cover a distance in a predictable time and / or at a controlled speed, in order, in particular, to transport cargo or passengers, or to carry out specific operations during this movement such as fishing, exploration or even the laying of submarine cables without these examples being limiting, and this whatever the wind conditions.

[0054] Vertical direction is perpendicular to the waterline of the vessel.

[0055] Sail thrust defines a mechanical thrust generated by the rotating sail subjected to a wind perpendicular to its axis independently of the production of engine torque and electricity production. This mechanical thrust exists when the rotary wing is free to rotate around its axis, it also exists when the rotary wing, subjected to the wind, produces engine torque and operates as a wind generator.

[0056] Aero-propulseur designates a mode of operation where the rotary wing is driven in rotation by motor means and behaves like an airplane propeller.

[0057] Real wind is the wind as it blows characterized by a vector whose direction is that of the wind and the norm its speed.

[0058] Apparent wind is the vector sum of the real wind and the ship's forward speed, represented by a vector whose direction is that of the ship and the norm the speed of the ship, it is in a way the wind felt on the deck of the ship.

[0059] Drag, whether hydrodynamic or aerodynamic, is a force that opposes the movement of the ship.

[0060] The propulsive force is the projection onto the direction of movement of the ship of the resultant of the thrusts produced by the ship's propulsion means and the drag.

[0061] Although the device which is the subject of the invention can, under certain specific conditions, provide 100% of the propulsion needs of a ship, in the context of the transformation / renovation of an existing ship, already provided with propulsion means, generally by an internal combustion engine, the objective is to provide propulsion assistance means making it possible to reduce overall consumption by at least 30%, preferably by at least 50%.

[0062] Thus, in general, the device which is the subject of the invention is intended to operate in concert with propulsion means already existing on the ship, with the aim of reducing their consumption.

[0063] [Fig-1] according to a schematic example of embodiment a ship (100) implementing The invention comprises a displacement hull (10) carrying motorized propulsion means, for example in the form of an internal combustion engine (20) driving a propeller (21).

[0064] The ship is characterized in particular by its drag in a range of speeds of movement of the ship and the wind to which it is subjected. The total drag of the ship is composed of:

[0065] - the drag of the hull, superstructures and appendages;

[0066] - the drag of its hydrodynamic propulsion means

[0067] - the drag of sail propulsion devices

[0068] Those skilled in the art understand that the propulsion means, whether hydrodynamic (propeller 21) or sail / aerodynamic (115), are capable of producing mainly a propulsive force and / or drag depending on their mode of use.

[0069] The ship comprises a sail propulsion device (101) comprising a mast (111) extending in a vertical direction (110) relative to the hull, on which is installed a rotary wing (115) capable of rotating around an axis (116) secant relative to the vertical direction (110).

[0070] According to this schematic example of embodiment, the rotary wing is installed in a nacelle (120) in pivot connection around the vertical axis at the top of the mast (111).

[0071] The rotary wing comprises blades (115b 1152) in wing profile, which can be oriented by an appropriate mechanism around an axis (117) substantially perpendicular to the axis of rotation (116) of the rotary wing so as to vary the pitch of said rotary wing.

[0072] According to this exemplary embodiment, the nacelle (120) comprises an electric generator (121), connected to a battery (130).

[0073] Thus, according to this exemplary embodiment, the sail propulsion device is presented as a wind turbine but its use differs from that of a wind turbine.

[0074] When the sail propulsion device is subjected to a wind (190) of speed Vo, this tends to turn the rotary sail producing both a rotational power proportional to the surface swept by the blades (115i, 1152) during their rotation and to V03, as well as a sail thrust substantially perpendicular to the plane of rotation of the rotary sail, proportional to the surface swept by the blades and to V02.

[0075] If the blades are left free to rotate, that is to say that the electric generator (121) does not produce any resistive torque, the rotational power is zero and the propulsive force results from the sail thrust.

[0076] Conversely, if the blades are locked in rotation, the rotational power is also zero and the surface exposed to the wind is limited to the surface of the blades. The sail thrust is then a function of the orientation of the blades around their axis (117).

[0077] Between these two extreme cases and in particular depending on the orientation of the blades around their axis (117) and the orientation of the apparent wind relative to the axis of the rotor, it is possible to adjust the proportion of sail thrust and rotation power, the latter making it possible to produce electrical energy to power the battery.

[0078] The sail thrust makes it possible to propel the ship at a speed V (150) so that the sail thrust and the rotational power are in reality proportional to the apparent wind speed (Vo-V) (in vector relation) and must be adjusted accordingly.

[0079] Thus, the sail thrust on the rotary wing (115) can be used to participate in the propulsion of the ship while producing electricity which can be stored in the battery.

[0080] According to one embodiment, the simplest, the sail propulsion device assists, by the sail thrust, the motorized propulsion means reducing their consumption, the energy produced by the rotational power is stored in the battery and is used for purposes other than the propulsion of the ship, for example to power refrigeration means or any other equipment on board the ship.

[0081] [Fig.2] in a configuration of progression of the ship in headwind (290), the With the rotary sail facing the wind, the ship moves forward at a speed (250) using the motorized propulsion means. The sail thrust on the rotary sail produces aerodynamic drag which opposes the movement of the ship.

[0082] However, according to a first embodiment, this drag can be considerably reduced by blocking the rotation of the wing and by orienting the blades appropriately.

[0083] According to a second embodiment, the ship is provided with an electric propulsion means making it possible to assist the propulsion of the ship under these conditions.

[0084] According to a first variant, the generator (221) driven by the rotary wing is reversible and can be used as a motor to drive the rotary wing.

[0085] The generator / motor (221) is powered by the battery, which may have been previously charged by means of said generator / motor (221) operating in generator mode and driven by the rotary wing.

[0086] Thus, according to this embodiment, the rotary wing, used as an aeropropulsor, makes it possible to generate a propulsive force and to assist the motorized means, or even to replace them for the propulsion of the ship.

[0087] According to another embodiment, compatible with the previous one, the ship is equipped with electric propulsion means (230) which make it possible to drive the propeller (21), alone or in combination with the internal combustion engine (20).

[0088] In this case, in the configuration of [Fig.2], headwind, the rotary sail can be driven in rotation and produce electrical energy capable of supplying the electric propulsion means (230), via the battery, which electric propulsion means assists the internal combustion engine (20) in propelling the ship, consequently reducing consumption.

[0089] Thus, this sail propulsion device is capable of assisting the propulsion of the vessel regardless of the wind direction, including in a headwind.

[0090] This device is also capable of producing and storing electrical energy even when the ship is at anchor, and can be brought into a minimal aerodynamic drag configuration if necessary.

[0091] [Fig.3] the sail propulsion device can be adapted to any type of vessel existing in order to achieve fuel consumption reduction rates of at least 30%, 50%, in simplified configurations and close to 100% in so-called complete configurations,

[0092] It thus offers a great deal of flexibility in adapting to an existing vessel depending on the use of this vessel and the cost envisaged for the transformation.

[0093] To this end, according to a first step (310) of data collection, the relevant technical information on the ship is collected, in particular with regard to the geometric, hydrodynamic and aerodynamic characteristics of the ship such as:

[0094] the characteristics of the hull: length, displacement, position of the center of gravity and the center of buoyancy;

[0095] hydrodynamic and aerodynamic drag as a function of speed.

[0096] These characteristics make it possible to construct a model of the ship that can be used for simulations.

[0097] According to a parallel step (320) of collecting the operating constraints, elements such as the maximum permissible height and width, for example for passage under bridges or in canals, the positioning and the size of the cargo or equipment on the deck are acquired. This information makes it possible to define the maximum size of the sail propulsion system as well as the possible retraction techniques thereof.

[0098] Finally, a step (330) of acquiring the navigation conditions comprises the acquisition of the targeted navigation speeds, in particular at least one reference cruising speed, the characteristics of the motorization means as well as the wind conditions in the targeted navigation zone.

[0099] For example, as a first approximation, the wind direction is predominantly west in the Atlantic with speeds between 11 m / s and 21 m / s, similar data are available for all navigation zones.

[0100] Most cargo or passenger ships travel at speeds between 5 knots and 20 knots (2.57 m / s to 10.29 m / s)

[0101] Although there may be special cases, the installation of such a sail propulsion system on a ship represents a cost which must be able to be amortized in operation, by the fuel savings achieved, over a reasonable period.

[0102] The system of the invention has a lot of flexibility to be adapted to different configurations.

[0103] In a first feasibility check, the elements set out below

[0104] However, having more than two masts poses difficulties both in terms of the occupation of the bridge than aerodynamic disturbances from one rotor to the other.

[0105] From this basis, to ensure a sufficient level of assistance leading to a reduction in emissions of the order of 50% in a wide range of wind and road conditions, the sail thrust in a tailwind, the rotary wing being oriented perpendicular to the wind, for an average wind speed Vm and a reference forward speed Vj of the ship's movement, must be at least equal to a proportion of the hydrodynamic drag force (DH) of the ship at this same speed, when the speed V07 of the real wind is equal to 2.5 times the forward speed Vj. (V0i=2.5 ■ V^.

[0106] Additionally, when the ship is equipped or is intended to be equipped with electric propulsion means, whether aerodynamic or hydrodynamic, the electric power generated by the rotors for a second speed V2 of movement of the ship with an average wind speed V02 is proportional to (Vo2± V2)3 depending on the orientation of the wind relative to the forward speed, the two speeds being added together in headwind conditions.

[0107] These conditions lead to a minimum surface swept by the rotary sails of sail propulsion devices which can be determined by the following equations:

[0108] [Math.l] 7- = lM(V0I-V,)2Cr

[0109] [Math.2] P^pAiy^ + vÿc,,

[0110] Where A is the surface swept by the rotors of the sail propulsion device, q is the density of the air, T the sail thrust and P the rotational power, CT and CP are coefficients which can be obtained by tables, databases or numerical calculations for the different embodiments of the sail propulsion system.

[0111] Thus in a general navigation situation where the rotors are oriented differently than perpendicular to the wind, the operation of the device consists of determining an optimal position of the rotors and the pitch of the blades to produce maximum propulsive force.

[0112] In the context of pre-dimensioning and the choice of the characteristics of a sail propulsion device, the sail thrust in a tailwind is considered to constitute a dimensioning parameter.

[0113] As will be shown later, this condition is in reality little used in real navigation situations, it only constitutes a remarkable case making it possible to determine a minimum configuration in terms of performance of the sail propulsion device, for a first choice of the latter.

[0114] The proportion is equal to 50% (T>0.5DH) for vessels whose length is less than 150 meters and 30% (T>0.3DH) for vessels whose length is greater than 150 meters. These limits are theoretical and are used for a first di- mentioning.

[0115] One of the reasons for this is that on large vessels it is possible to install two rotor-carrying masts. So that apart from particular operating points, including the point mentioned above, where due to aerodynamic disturbances between rotors only one rotor is really effective, the assistance levels produced by the sail propulsion device will be significantly higher.

[0116] For small vessels of less than 100 metres in length it will generally be difficult, but not necessarily impossible, to install 2 rotor masts; for vessels of intermediate length, between 100 m and 150 m, it is generally preferable to opt for a technical solution comprising 2 rotor masts, given the advantages of this solution.

[0117] The examples set out below show that these minimum requirements are easily exceeded,

[0118] The integration of the other constraints makes it possible to select the most appropriate embodiment.

[0119] One rotor per mast

[0120] According to a first embodiment, the sail propulsion device comprises a rotor per mast as shown [Fig.4] and [Fig.5], [Fig.4] for an example of a bulk cargo ship (400) and [Fig.5] for an example of a Suez class oil tanker (500).

[0121] [Fig.4]] and [Fig.5] generally for a vessel whose length is greater than or equal to 150 m, or even less, the sail propulsion device consists of 2 rotor-carrying masts (411, 412, 511,512) and spaced longitudinally on the hull.

[0122] The two masts (411, 412, 511, 512) are installed a longitudinal distance (Z) apart. Preferably, this distance is maximized taking into account the structural installation constraints and other constraints specific to the ship.

[0123] The total distance between the two masts is at least equal to 1.5 times the diameter of the blades of the rotary wing having the largest diameter, this in order to limit the aerodynamic disturbances between the rotors, knowing that in operation [Fig. 13] the rotors are generally oriented at an angle (1320) relative to the longitudinal direction (1310).

[0124] According to this embodiment, the rotors are installed in a pivot connection at the top of the masts and comprise a nacelle containing the various control mechanisms, in particular the pitch of the blades of the rotary wing, as well as an electric generator driven by the rotary wing. Advantageously, the electric generator is reversible and can be used as a motor to drive the rotary wing, which then operates in aero-propulsion mode.

[0125] Alternatively, or in addition, the pivot connection is located at the base of the mast or in a section of the mast close to its base.

[0126] The mast section (413) is advantageously profiled to limit its aerodynamic drag.

[0127] The rotary wing consists, for each rotor, of 2 blades (415b 4152, 515b5152), the section (415, 416) of which follows an aerodynamic wing profile, here shown solid but which can be hollow.

[0128] The aerodynamic profile of the blades is optimized to produce a sail thrust and for its control with the variable pitch mechanism.

[0129] In the case where the rotary wing is used solely driven by the wind, the section (415) is asymmetrical and the blades are twisted along their length.

[0130] In the case where the rotary wing is also used as an aero-propellant, the section (416) of the blades is preferably symmetrical and the blades are preferably free from twisting.

[0131] This two-blade configuration is important because it allows:

[0132] to reduce the lateral bulk of the sail propulsion device as well as its aerodynamic drag by aligning said blades with the mast,

[0133] to reduce the total height of the sail propulsion device by orienting the blades perpendicular to the mast.

[0134] Thus, the alignment of the blades with the mast makes it possible to reduce the impact of the device on visibility, in particular during maneuvers, to avoid hindering loading and unloading operations by crane or to put the devices in a configuration where they can be lowered towards the deck of the ship, for example for passage under a bridge.

[0135] The minimum surface determined previously gives the minimum diameter of the rotary wing and consequently a first mast height.

[0136] This minimum surface area and the corresponding mast height can be increased, increasing the potential efficiency of the sail propulsion device, as long as the stability of the vessel remains within acceptable limits. The two masts (511, 512) can be of different heights. Likewise, the 2 rotors can be provided with rotary sails of different diameters.

[0137] The stability of the ship depends on its mass, the position of its center of gravity, its center of hull and more generally on the characteristics of the hull, mainly with regard to the height of application and the intensity of the sail thrust and to a lesser extent, the displacement of the center of gravity by the installation of the rotors.

[0138] [Fig.6] according to an exemplary embodiment the electric generator (621), whether of the generator only type or of the generator / motor type, can be placed inside the mast (611) on a platform (630) so as to lower the center of gravity of the sail propulsion device. A mechanical connection comprising a homo- kinetic (625) allows the driving of said electric generator by the rotary wing (615), and the driving of the rotary wing in aero-propulsion when it is a generator / motor.

[0139] According to an embodiment not shown, the generator or generator / motor may be placed on a deck of the ship and be connected to the rotary sail by a mechanical or hydraulic connection.

[0140] According to yet another embodiment, the generator and the drive motor of the rotary wing for its operation as an aero-propulsor are two separate entities placed at different locations chosen from the nacelle, the interior of the mast or on a deck of the ship.

[0141] The envelope of the volume covered by the sail propulsion device as a function of the wind direction is a sphere (490), it is appropriate to check that this does not interfere with structures of the ship or its cargo.

[0142] [Fig.7] when passing under a bridge or in other similar situations, except the solution consisting of orienting the rotary sails so that the blades are perpendicular to the mast and thus reducing the total height of the sailing device, according to one embodiment, the masts (411, 412) comprise a section in pivot connection around an axis perpendicular to the vertical direction, relative to a section of the fixed mast in connection with the hull.

[0143] According to variants, this pivot connection is located at or near the base of the mast and a deck of the ship or higher on the mast.

[0144] According to alternative embodiments, this pivot connection allows the upper section of the mast to pivot relative to the fixed section by an angle between 0° and 180°. For an angle of 0°, the mast is vertical, the two sections are aligned, for an angle of 180° the two sections are parallel.

[0145] In order to achieve these rotations, the blades are first aligned with the mast.

[0146] In the example presented [Fig.7] the pivot connection is located at the bridge level and the upper section can be tilted through a 90° angle to lower the sail propulsion devices close to the ship's deck (400).

[0147] To this end, the two masts carrying the rotors are offset by a transverse distance e according to the width of the hull. The presence of this offset also makes it possible to limit the impact of the presence of the sail propulsion device on visibility and also to reduce aerodynamic disturbances between the rotors of the masts.

[0148] Multirotor masts

[0149] [Fig.9] according to another embodiment of the sail propulsion device of the ship (900), this comprises a plurality of rotors, here 5, per mast (911,912), distributed in the vertical direction of the mast.

[0150] This configuration makes it possible to distribute the sail thrust over the height of the mast and allows in particular, for equivalent sail thrust, to affect the stability of the vessel less, or for a given stability limit to obtain a greater sail thrust.

[0151] The envelope of the volume covered by the sail propulsion device as a function of the wind direction is an ellipsoid (690) which can also be advantageous for certain types of vessels.

[0152] This configuration also makes it possible to reduce the distance required between the masts with respect to aerodynamic disturbances, compared to the solution with a single rotor per mast.

[0153] Thus, the use of multi-rotor masts can allow, when the configuration of the ship lends itself to it, the installation of more than two masts.

[0154] [Fig-8] As a first approximation, from the point of view of the sail thrust, a plurality N of rotors of diameter d superimposed on a mast, provided that the trajectories of the rotary wings are contiguous or almost contiguous, produces a sail thrust of the same order of magnitude as a single rotary wing whose diameter D is the sum (Nd) of the diameters of the rotary wings of the plurality.

[0155] Thus, 4 superimposed rotors whose rotating wings have a diameter of 15 meters produce a sail thrust of the same order of magnitude as that of a single rotor whose rotating wing diameter is 60 meters.

[0156] Alternatively, the rotors of the plurality do not have the same diameter but the trajectories of the rotating wings are nevertheless contiguous or almost contiguous with a distance between the blade ends of the order of 1 / 20th of the rotor diameter.

[0157] [Fig. 10] advantageously the masts (611, 612) carrying the plurality of rotors com take one or more telescopic sections allowing the said masts to be retracted to a lower height, for example to pass under a bridge, after having oriented the blades of the rotary sails perpendicular to the mast.

[0158] Those skilled in the art understand that a mast, whether comprising a single rotor or a plurality of rotors, may comprise both one or more telescopic sections and a section pivotally connected relative to a fixed section so as to tilt said pivotally connected section, the pivotally connected section and / or the fixed section comprising a telescopic section.

[0159] Similar to the solution comprising one rotor per mast, the pivot connection of the rotors around the vertical direction of the mast is carried out individually for each rotor or the mast has at its base a pivot connection around the vertical axis allowing all the rotors to be oriented at the same time, these two variant embodiments not being mutually exclusive. This configuration takes into account in particular the fact that for a mast whose height is around 100 meters in certain applications, the wind conditions, in particular speed, are not the same at the top of the mast only near the ship's deck.

[0160] Masts

[0161] [Fig.4] whatever the embodiment, single-rotor or multi-rotors, the section (413) of the masts is advantageously profiled to limit their aerodynamic drag, or the masts include an aerodynamic fairing for this purpose.

[0162] Advantageously, the mast, particularly when it comprises an orientation device at its base in addition to a nacelle orientation device at its top, can be used as a rigid sail by being oriented appropriately with respect to the wind, thus providing additional sail thrust.

[0163] In the case of a multi-rotor mast, the operation of the rotors in aeropropulsive mode cooperates with the profiled mast to produce a thrust force via the mast acting as a wing under the effect of the aerodynamic flow caused by said rotors, in addition to the aeropropulsive thrust

[0164] According to an exemplary embodiment not shown, the masts consist of a lattice structure on which an aerodynamic fairing is fixed.

[0165] Electric motor

[0166] According to embodiments, the device which is the subject of the invention advantageously comprises an electric propulsion means.

[0167] According to a first embodiment, these electric propulsion means (221 [Fig.l]) directly drive the rotary wing which functions as an aeropropulsor. This mode of operation is possible both in the single-rotor configuration and in the multi-rotor configuration.

[0168] According to another embodiment substitutable or complementary to the first embodiment, the electric propulsion means comprise an electric motor (230 [Fig.l]) capable of driving, alone or with the assistance of the internal combustion engine, at least one propeller (21 [Fig.l]) for hydrodynamic propulsion of the ship.

[0169] According to exemplary embodiments, the electric motor driving the propeller is pre-existing, for example when the ship comprises an internal combustion propulsion device (diesel or gas turbine) coupled to an electric motor, or the electric motor is installed during the modification of the ship and the installation of the sail propulsion device.

[0170] As a non-limiting example, such electrical devices known as PTO / PTI can be installed on an existing propeller shaft and are capable of operating in concert with the internal combustion engine, either in assistance, or by providing 100% of the necessary propulsion power, or in regenerative braking by absorbing mechanical energy and transforming it into electrical energy which can be stored in a battery or used directly on board, or in generator mode driven by the internal combustion engine or by the free rotation of the propeller. under the effect of the hydrodynamic flow generated by the movement of the ship.

[0171] Such PTO / PTI devices suitable for installation on an existing vessel are for example offered by the Swedish company Asea Brown Boveri Ltd (ABB®) for powers of up to 6 MW.

[0172] [Fig. 11] 1 in a general case corresponding to a so-called complete system, the electricity produced by the rotor passes through a rectifier (720) then is directed towards a power distributor (730).

[0173] The distributor distributes the electrical power to and from the PTO / PTI device, to and from the battery and to the on-board uses (740) if applicable.

[0174] The power distributor is also capable of directing power to the engine or generator / motor driving the rotary wing in aero-propulsion mode.

[0175] The PTO / PTI device is capable of driving the propeller (21) and delivering power to it via a transmission shaft (750) alone or with assistance from the heat engine.

[0176] The PTO / PTI device is also capable of producing electrical energy, being driven by the transmission shaft (750), the latter being driven either by the propeller (21), for example in a regenerative braking situation, or by the heat engine.

[0177] The electrical power produced by the PTO / PTI device is directed to the power distributor (730) and redirected according to the needs of the navigation conditions.

[0178] To this end, a control device (790) comprising a piloting program controls the different power sources and their distribution according to the navigation conditions so as to remain within the targeted emission reduction conditions.

[0179] Operation

[0180] [Fig.l2A] to [Fig.l2D] show examples of operation of the sail propulsion device in different wind conditions, other than tailwind and headwind, and which correspond to the usual operation of the device with the rotors oriented at an angle a relative to the apparent wind. The tailwind and headwind conditions are essentially cited as design bases, although the device is capable of operating in these conditions, they do not constitute usual operating conditions.

[0181] Although not an absolute rule, the best results are generally obtained when the rotary sail is oriented substantially perpendicular to the true wind in upwind, downwind, downwind and beam conditions. In upwind conditions the rotary sail is oriented substantially parallel to the vessel's axis.

[0182] [Fig. 13] It should be noted that when the device comprises two masts equipped with rotors the orientation of the rotating sails other than perpendicular to the longitudinal direction tudinal (1310) of the hull, considerably limits the aerodynamic disturbances of the rotors of one mast on the rotors of the other mast, including for sailing conditions with downwind and headwind.

[0183] The rotor orientation means allow the rotary wing to be oriented in any direction relative to the wind. By playing on this orientation and on the orientation of the blades (pitch) it is possible to find optimal conditions for generating a propulsive force whatever the wind conditions.

[0184] In all the cases shown, the rotary wing (115) is oriented at an angle a relative to the direction of the apparent wind (1195). The vector representing the apparent wind is the vector sum of the real wind (1190) and the speed vector (1150) of the ship's movement.

[0185] [Fig. 12A] the vector representing the apparent wind (11951) is perpendicular to the direction of progression (150) and to the speed (11500) of the ship. Under these conditions the rotary sail is for example left free to rotate and produces a sail thrust (1191i) which is projected onto the direction of progression (150) as a propulsive force TA

[0186] [Fig. 12B] the projection of the vector (11952) representing the apparent wind on the direction of progression of the ship is parallel to the speed vector (11502) of movement of the ship. Under these conditions the rotary wing acts both as a sail producing a sail thrust (11912) and as a wind generator producing a torque (11922) and a rotary power, transformed into electrical energy, which can power an electric motor of the PTO / PTI type to produce a hydrodynamic thrust by driving the propeller of the motorized propulsion means. The propulsive force TA is the sum of this hydrodynamic thrust of the propeller and the projection of the sail thrust (11912) on the direction (150) of progression of the ship. Alternatively, all or part of the electrical production of the rotos can be used to charge the battery.

[0187] [Fig. 12C] the projection of the vector representing the apparent wind (11953) onto the direction (150) of progression of the ship is in the opposite direction to the speed (11503) of the ship in close-hauled navigation. Under these conditions, the sail propulsion device is used as a wind generator producing a torque (11923) and a rotational power which, transformed into electrical power, is capable of supplying the PTO / PTI type electric motor to assist the motorized propulsion means. The sail propulsion device produces a sail thrust (11913) which, projected onto the direction of progression of the ship, opposes this progression. The resistance power generated by this aerodynamic drag is less than the electrical power produced, so that the sail propulsion device produces assistance

[0188] In an extreme case, particularly in a headwind, the sail propulsion device can be placed in a minimal aerodynamic drag configuration, for example by aligning the blades of the rotary wing (115) with the mast and stopping their rotation. The vessel can then move forward by means of the electric motor drawing its power from the battery.

[0189] It should be noted that in most of the ships concerned by the invention it is possible to house a battery with a capacity of several MWh and that this is capable of powering the PTO / PTI device for several hours while the latter assists or ensures the propulsion of the ship alone.

[0190] [Fig. 12D] corresponds to a downwind sailing situation in light winds. The rotary wing is driven in rotation, for example by drawing energy from the battery and produces a sail thrust (11914) which produces a propulsive force, in parallel the motorized means, driven by the PTO / PTI device or the thermal engine can produce an additional propulsive force.

[0191] Those skilled in the art understand that if the vessel is equipped with both a PTO / PTI device and a sail propulsion device capable of operating in aeropropulsion mode, both devices can be used at the same time.

[0192] Also, the objective being to produce propulsion assistance making it possible to reduce greenhouse gas emissions and other pollutants, the thermal motorization means can be used in conjunction with the sail propulsion device either to propel the vessel or to produce electricity, via the PTO / PTI device, in particular to recharge the battery.

[0193] In practice, large internal combustion engines cannot be stopped and restarted repeatedly. Consequently, the device which is the subject of the invention, particularly when adapted for conversion on large ships, aims above all to maintain the operation of the thermal engine below a power threshold.

[0194] The transition from one operating mode to another is carried out depending on the wind, in particular by the orientation of the rotors, and by the distribution of the powers produced and consumed.

[0195] [Fig.l4A] to [Fig.l4C] shows examples of operation in different wind and forward speed conditions for a vessel comprising 2 single-rotor masts similar to the vessel shown [Fig.4] and whose characteristics are given [Table 1]. They show in particular a preferential orientation of the rotors in these conditions. In all cases the hydrodynamic drag of the hull at 12 knots is 153 kN.

[0196] [Fig.l4A] in a close-hauled sailing condition, a ship's forward speed (1150) of 12 knots, a true wind (1191) of 20 knots, oriented at 40° relative to the ship's progress.

[0197] Under these conditions the rotors turn and produce 1 MW of electrical power. The rotors are oriented at an angle a of the order of 30° relative to the apparent wind (1195) their aerodynamic drag is of the order of 8 kN, in the direction of progress of the ship, the effect of this force on the hull produces an additional drag of the hull of 11 kN, due to drift and heel. The electrical power supplied is supplemented by the battery, it could be supplemented by a thermal engine, so as to deliver 1.1 MW to the propeller which produces a propulsive force of 172 kN. Taking into account the electrical and mechanical losses this situation allows a saving of 46% of propulsion power.

[0198] [Fig.l4B] in a close-hauled sailing condition, a ship's forward speed (1150) of 12 knots, a true wind (1191) of 30 knots, oriented at 35° relative to the ship's progress.

[0199] The rotors are oriented at an angle a of 40° relative to the apparent wind so as to limit their aerodynamic drag in the direction of progress of the ship, here of the order of 64 kN. This force induces an additional drag of the hull of 12 kN. The rotors produce an electrical power of 2.6 MW which is directed towards the engine driving the propeller which, taking into account the losses, delivers a propulsive power of 1.4 MW and a thrust of 230 kN. In this configuration, the sail propulsion device produces 100% of the power necessary for the propulsion of the ship.

[0200] [Fig.l4C] In a crosswind sailing condition, the ship's forward speed (1150) is 12 knots, the true wind speed (1191) is 30 knots, oriented at 90° relative to the ship's direction of progress.

[0201] The rotors are oriented at an angle a of 42° relative to the apparent wind direction (1195). The rotors produce a total sail thrust of 165 kN; this force introduces an additional hull drag of 12 kN, so that the sail thrust is sufficient to propel the ship. But in addition, the rotors produce 2.2 MW of electrical power which can be, for example, stored in the battery. Thus, the assistance generated by the sail propulsion device reaches 243%, taking into account electrical and mechanical losses.

[0202] [Fig. 14D] represents a close-hauled sailing condition with a true wind (1191) of 20 knots, oriented at 65° to the ship's forward speed (1150) of 12 knots.

[0203] The rotors are oriented at an angle a of 30° relative to the apparent wind, the rotors produce both a sail thrust of 73 kN and an electrical power of 0.9 MW. The sail thrust produces an additional hull drag of 12 kN. The electrical power produced by the rotors is directed to the motorized propulsion means which, taking into account electrical and mechanical losses, produce a propulsive power of 0.6 MW and a propulsive force of 92 kN. Thus, assistance reaches 99%.

[0204] These examples show that the sail propulsion device makes it possible to assist the ship's propulsion means in significant proportions, which can exceed 100%, even when the ship is going upwind.

[0205] Thus, by choosing the operating mode of the sail propulsion device depending on the wind, the thermal means can be maintained at an operating power lower than a determined threshold, thereby reducing greenhouse gas emissions and other pollutants, while maintaining the battery at a desired charge level.

[0206] Returning to [Fig.3], if during a pre-dimensioning step (340) the constraints are analyzed, and in particular the stability constraints.

[0207] If it is possible to define a sail propulsion device implementing one or two masts provided with rotors and offering a sufficient surface area to produce sail thrust at the required level, then during a design step (350) the characteristics of the sail propulsion device and, where appropriate, of the PTO / PTI device are refined as a function of the initial constraints and by simulation of the operating conditions.

[0208] Following the simulation design steps, the performance of the system integrating, for example, a sail propulsion device with two masts carrying rotors capable or not of operating in aero-propulsion mode and a PTO / PTI device are summarized in a diagram (370) giving the level of assistance for a given speed as a function of the direction of the wind and its speed, each polar (371, 372, 373, 374) corresponding to a real wind speed.

[0209] This diagram shows that 1 the levels of assistance achievable are quickly significant, of the order of 100% and even more as soon as the wind direction deviates from the vertical axis (tailwind - headwind), but nevertheless remain significant in these extreme conditions. Examples

[0210] The examples set out below show that the minimum conditions are easily met and exceeded provided that the vessels in question are sufficiently large in size. Indeed, the inclining and righting moments which define the stability of the vessel in the presence of sail propulsion devices and consequently, which structurally limit the height and power of these devices are respectively proportional to the square and cube of the length of the hull, so that for vessels of length greater than approximately 100 meters, the devices installed are capable of producing propulsion assistance of at least 50% in all circumstances, the remaining constraints essentially concerning questions of size and cost,

[0211] A first example of embodiment corresponds to the ship, bulk carrier, represented [Fig.4] whose characteristics are summarized in the table below:

[0212] [Tables 1] Length 138 m Beam 18 m Draft 6.5 m Cruising speed 12 knots Displacement 11,570 t Empty weight 8,210 t Gross tonnage 7,548 t Engine power (electric) 2,700 kW

[0213] For this vessel, an example of a sail propulsion device comprises two single-rotor masts with the following characteristics:

[0214] [Tables2] Rotor diameter 60 m Mast height 43.5 m Number of blades per rotor (symmetrical profile) 2 Total rotor power 3,000 KW

[0215] At 12 knots forward speed the hull produces a drag force of 153 kN,

[0216] In tailwind conditions (similar to [Fig.l]) with a true wind speed of 30 knots, or 2.5 times the ship's forward speed, the sail propulsion system can produce a thrust force of 294 kN, or almost double the ship's drag. In practice, it is then possible to use the propeller of the motorization means in regenerative braking to brake the ship and produce energy.

[0217] In tailwind conditions with a true wind speed of 20 knots, i.e. less than twice the ship's forward speed, the sail propulsion device produces a sail thrust of 141 kN, i.e. 92% of the ship's drag.

[0218] It should be noted that in these tailwind situations where the axis of rotation of the rotary wings is oriented parallel to the true wind, the aerodynamic disturbances between rotors mean that these sail thrust conditions are obtained in practice with a single rotor.

[0219] For this same vessel, in a headwind situation (similar to [Fig.2]) with a ship's forward speed at 8 knots and a real wind with a speed of 22 knots, the sail propulsion device, acting as a wind generator, produces 40% of the power required to propel the ship by electric motorized means.

[0220] With a ship's forward speed of 12 knots and a real wind speed of 25 knots, the sail propulsion device, acting as a wind generator, produces 15% of the power required to propel the ship by electric propulsion means.

[0221] In the same way as for the tailwind, the headwind situation is not favorable due to the aerodynamic disturbances generated from one rotor to the other, so that in practice the device operates in these conditions as if it had almost only one rotor.

[0222] The following examples show examples of pre-dimensioning of the sail propulsion device for different vessels, based on a single-rotor mast. This pre-dimensioning must then be refined according to the other technical constraints.

[0223] According to a 3rd example, corresponding to a bulk carrier, with an overall length of 127 m, beam of 21.2 m and DWT (deadweight tonnes) of 14,130 tonnes, equipped with a 4.4 MW thermal engine, maximum speed 16 knots, the following results are given as a function of different reference speeds and different rotor diameters:

[0224] [Tables3] Reference speed (knots) 4 6 8 10 12 14 16 True wind speed (knots) 10 15 20 25 30 35 40 Apparent wind speed (knots) 6 9 12 15 18 21 24 Vessel drag (kN) 25 53 92 144 222 348 551 Sail thrust Rotor 60 meters [kN] 14.4 32.3 57.5 89.8 129.3 176.0 229.9 as % of drag 58% 61% 62% 62% 58% 51% 42% Sail thrust Rotor 80 meters [kN] 25.5 57.5 102.2 159.6 229.9 312.9 408.7 as % of drag 103% 108% 111% 111% 104% 90% 74% Sail thrust Rotor 100 meters [kN] 39.9 89.8 159.6 249.4 359.2 488.9 638.5 as % of drag 161% 169% 173% 173% 162% 140% 116%

[0225] These results show that the sail thrust condition of 50% of the drag is achieved with a rotor of 60 meters in diameter. Even if a single single-rotor mast allows the result to be achieved, the use of 2 single-rotor masts possibly of a smaller diameter, if the installation distance condition can be respected, can however be judicious.

[0226] According to a fourth example concerning a bulk carrier with an overall length of 171.7 m, beam 27 m, DWT 28,356 tonnes, a 4.95 MW thermal engine:

[0227] [Tables4] True wind speed (knots) 10 15 20 25 30 35 40 45 Apparent wind speed (knots) 6 9 12 15 18 21 24 27 Vessel drag (kN) 37.2 80.0 137.9 212.3 311.5 455.8 674.2 994.7 Sail thrust Rotor 60 meters [kN] 14.4 32.3 57.5 89.8 129.3 176.0 229.9 290.9 as % of drag 39% 40% 42% 42% 42% 39% 34% 29% Sail thrust Rotor 80 meters [kN] 25.5 57.5 102.2 159.6 229.9 312.9 408.7 517.2 as % of drag 69% 72% 74% 75% 74% 69% 61% 52% Sail thrust Rotor 100 meters [kN] 39.9 89.8 159.6 249.4 359.2 488.9 638.5 808.2 as % of drag 107% 112% 116% 117% 115% 107% 95% 81%

[0228] According to this example, a rotor diameter of the order of 80 m, more precisely between 60 m and 80 m, would be necessary to obtain a sail thrust of the order of 50% of the drag. However, due to the length of the hull (171 m), it would be difficult to install two 80 m rotors while maintaining a distance of 1.5 times the diameter between them. However, given the operating modes presented above, it is preferable in this case to install two 60 meter rotors, the 60 m rotor meeting the condition of sail thrust equal to 30% of the drag.

[0229] According to a 5th example, concerning a bulk carrier with an overall length of 285 m, beam 45 m, DWT 180,915 tonnes, with a 15.45 MW thermal engine and a maximum speed of 16.7 knots:

[0230] [Tables5] Reference speed (knots) 4 6 8 10 12 14 16 True wind speed (knots - downwind) 10 15 20 25 30 35 40 Apparent wind speed (knots) 6 9 12 15 18 21 24 Vessel drag (kN) 103.2 221.8 381.8 582.5 825.9 1124.1 1511.0 Sail thrust Rotor 60 meters [kN] 14.4 32.3 57.5 89.8 129.3 176.0 229.9 as % of drag 14% 15% 15% 15% 16% 16% 15% Sail thrust Rotor 80 meters [kN] 25.5 57.5 102.2 159.6 229.9 312.9 408.7 as % of drag 25% 26% 27% 27% 28% 28% 27% Sail thrust Rotor 100 meters [kN] 39.9 89.8 159.6 249.4 359.2 488.9 638.5 as % of drag 39% 40% 42% 43% 43% 43% 42%

[0231] Thus, according to this example, the choice would be oriented towards two rotors with a diameter between 80 m and 100 m, or their equivalent in multi-rotor masts.

[0232] The above description and the exemplary embodiments show that the invention achieves the intended aims and makes it possible for ships of any size to obtain a reduction in thermal engine emissions of at least 30%, preferably at least 50%, regardless of the route and wind conditions.

Claims

Claims

1. A ship (100, 400, 500, 900) comprising a displacement hull (10) and motorized propulsion means (20), the ship producing hydrodynamic drag for a reference forward speed (150), comprising a sail propulsion device comprising a mast (111, 411, 412, 511, 512, 911, 912) extending in a vertical direction (110), a rotor comprising a rotary wing (115) capable of rotating about an axis of rotation (116) intersecting the vertical direction, the rotor being carried by the mast and comprising a device for orientation about the vertical direction, characterized in that the rotary wing (115) is capable, when subjected to a wind, of producing a sail thrust (1191) to propel the ship and an engine torque (1192) around the axis of rotation.

2. A vessel according to claim 1, wherein a length of the hull is less than 150 meters, the reference forward speed (150) is between 5 knots and 20 knots and the sail thrust (1191), under a tailwind whose actual speed is equal to 2.5 times the reference forward speed, is equal to 50% or more of the hydrodynamic drag of the vessel at said reference forward speed.

3. A vessel according to claim 1, wherein a length of the hull is greater than 150 meters, the reference forward speed (150) is between 5 knots and 20 knots and the sail thrust (1191), under a tailwind whose actual speed is equal to 2.5 times the reference forward speed, is equal to 30% or more of the hydrodynamic drag of the vessel at said reference forward speed.

4. A vessel according to claim 2 or claim 3, wherein the sail propulsion device consists of two masts (411, 412, 511, 512, 911, 912) spaced apart by a longitudinal distance (Z), each mast carrying at least one rotor.

5. A vessel according to claim 4, wherein the two masts are spaced apart by a transverse distance (e).

6. A vessel according to claim 1, wherein the mast carries a single rotor whose rotating wing consists of two blades (415b 4152) one section of which is an aerodynamic wing profile (415, 416), the rotor comprising a mechanism for orienting the blades around an axis (117) relative to the rotor.

7. A vessel according to claim 1, comprising an electric battery

8.

9.

10.

11.

12.

13.

14.

15.

16. (130), the sail propulsion device comprising an electric generator (121) driven by the rotary wing (115). Vessel according to claim 7, in which the sail propulsion device comprises a nacelle (120) connected to the mast and carrying the rotor, the electric generator (121) being housed in the nacelle. A ship according to claim 8, wherein the electric generator (621) is housed inside the mast or on a deck and is connected to the rotor by a mechanical (625) or hydraulic connection capable of transmitting mechanical rotational power from the rotary wing for driving the electric generator. A ship according to claim 7, wherein the motorized propulsion means comprises electric drive means (230). A ship according to claim 10, wherein the electric drive means are reversible and capable of producing electricity when driven. Vessel according to claim 1, in which the sail propulsion device comprises a plurality of rotors distributed on the mast (911, 912) in the vertical direction. A vessel according to claim 1, wherein the mast (911, 912) comprises a telescopic section. Vessel according to claim 1, in which the mast (411, 412) comprises a section tilting around a pivot with an axis perpendicular to the vertical direction. A vessel according to claim 1, wherein a section of the mast (413) is profiled so as to reduce aerodynamic drag of the mast. Vessel according to claim 1, comprising an electric motor (221) capable of driving the rotary wing (115) so as to operate the rotary wing as an aero-propulsion vehicle.

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