Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
  • B63B39/02—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses
  • B63B39/03—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses by transferring liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
  • B63B25/12—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed
  • B63B25/16—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed heat-insulated
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B43/00—Improving safety of vessels, e.g. damage control, not otherwise provided for
  • B63B43/02—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking
  • B63B43/04—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking by improving stability
  • B63B43/06—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking by improving stability using ballast tanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
  • B63B2025/085—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid comprising separation membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
  • B63B2025/087—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid comprising self-contained tanks installed in the ship structure as separate units
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
  • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
  • B63B2035/4486—Floating storage vessels, other than vessels for hydrocarbon production and storage, e.g. for liquid cargo

Definitions

• the invention relates to a transport vessel comprising an attitude control system, more particularly a transport vessel comprising an attitude control system not communicating with the sea.
• seawater ballast which can be filled, or partially filled, with seawater.
• the seawater ballast tanks are filled in such a way as to sink the ship in the water, in other words increase its draft or even raise the ship's waterline.
• the propulsion propeller(s) are completely submerged, which avoids a lift-off phenomenon of the propeller or propellers. It also prevents the draft at the front bow of the ship from being too shallow, which can occur in a cargo ship because the ship's equipment is most often located at the rear of the ship.
• a ship equipped with such seawater ballasts is described for example in document GB 2 044 201 A.
• a roll attenuator tank known as RST for "Roll-Stabilizing Tank” or ART for "Anti-Roll Tank”.
• RST Roll-Stabilizing Tank
• ART Anti-Roll Tank
• Such a roll attenuator tank has a larger dimension which is along a transverse axis of the ship. It is intended to be partially filled with seawater. The flow of seawater present in the roll attenuator tank is slowed down by one or more partitioning walls, this creating a moment which tends to attenuate the roll of the ship.
• the ballast tanks and the roll attenuator tank are filled with seawater.
• the ship loads seawater when leaving its port of departure, and releases this seawater when arriving its port of destination. In doing so, it transports aquatic organisms from one geographic area to another, posing risks to seaport ecosystems. For this reason, regulations increasingly tend to impose decontamination or sterilization of ballast water before it is released. Suitable equipment for this exists but has the disadvantage of being expensive.
• An idea at the base of the invention consists in proposing a system for controlling the attitude of a transport ship, which system makes it possible to eliminate the disadvantages linked to seawater ballast tanks.
• Another idea at the base of the The invention consists in making it possible to activate or deactivate at will an attenuation of the roll of the ship by this attitude control system.
• the ship does not load or release seawater during its journey, which avoids all the aforementioned drawbacks relating to seawater ballasts.
• the ship carries a volume of liquid, for example a fixed volume, which is not intended to be released into the sea.
• the distribution device makes it possible to distribute this volume of liquid between the tank(s) front fluid reservoir, rear fluid reservoir(s), and roll dampening reservoir. Consequently, the dispensing device makes it possible to modify the trim of the vessel at will, these modifications of the trim of the vessel being limited only by the volume of liquid and by the respective filling volumes of the tanks.
• the dispensing device also makes it possible to activate or deactivate at will the attenuation of the roll of the ship by the roll attenuator tank, by partially filling the latter with liquid.
• such a transport vessel may have one or more of the following characteristics.
• the liquid is a liquid having a density approximately equal to 1, for example between 0.95 and 1.05.
• the liquid is fresh water.
• the roll attenuator tank comprises a pair of partitioning walls, preferably facing each other, more preferably parallel to the longitudinal axis of the ship.
• the dispensing device can in principle be operated manually by the ship's crew, by closing or opening the relevant valves or by activating or deactivating the at least one pump, as required.
• the ship comprises a control unit configured to control the dispensing device according to a program and/or commands received from a man-machine interface.
• control unit is configured to, in response to a roll attenuation command, control the dispensing device to transfer liquid to the roll attenuator reservoir until the roll attenuation reservoir roll is filled between 25% and 75% of its maximum filling volume.
• control unit makes it possible to activate or deactivate at will the attenuation of the roll of the ship by the roll attenuator tank.
• the roll attenuation command can for example be entered manually by a member of the crew, when the latter observes that the navigation conditions are likely to lead to excessive rolling of the vessel.
• control unit is further configured to control the distribution device according to the weight of a load of the ship and the maximum load weight capacity P TC of the ship.
• the maximum loading weight capacity P TC of the aforementioned vessel is provided by the vessel builder, and therefore may be stored in memory in the control unit.
• the weight of the aforementioned ship's cargo can be entered by a member of the crew, for example at the start of the ship's journey.
• control unit is configured for, in response to the roll attenuation command and when the ship's load has a weight between 0.2*P TC and 0.8*P TC , controlling the dispensing device to transfer fluid to the roll attenuator reservoir from the front fluid reservoir and/or the rear fluid reservoir, preferably from the front fluid reservoir and the rear fluid reservoir and/or so as not to not increase the draft at the bow of the vessel.
• control unit is configured to, in response to the roll attenuation command and when the ship's load has a weight less than or equal to 0.2*P TC , control the distribution device to transfer liquid to the roll attenuator tank from at least the forward liquid tank, preferably only from the forward liquid tank and/or so as not to increase the draft at the bow of the vessel.
• control unit is configured to, in response to the roll attenuation command and when the ship's load has a weight greater than equal to 0.8*P TC , control the distribution device for transferring fluid to the roll attenuator reservoir from the front fluid reservoir and/or the rear fluid reservoir, preferably from the front fluid reservoir and the rear fluid reservoir.
• the total weight P RT of the at least one front tank and of the at least one rear tank, when completely filled with a liquid of density equal to 1, represents between 2% and 8%, preferably between 3% and 6%, of the empty weight P v of the vessel.
• the total weight P ART of the roll attenuator tank when the latter is filled with a liquid of density equal to 1, represents between 1% and 4%, preferably between 2% and 4%, the empty weight P v of the vessel.
• the attitude control system further comprises a central liquid tank, located in a zone comprised between 40% and 60% of a length L of the vessel along the longitudinal axis of the vessel.
• the central liquid tank can in particular make it possible, when it is partially or totally filled with liquid, to compensate for the bending stresses of the central region of the ship's hull along the longitudinal axis of the ship. This is beneficial for the life of the vessel.
• the roll attenuator tank is located in the first third, preferably in the first quarter, along a longitudinal axis of the ship.
• Other embodiments are however possible, in particular depending on the various installations and layouts of the ship.
• the dispensing device is configured to transfer liquid from said at least one rear liquid reservoir to the roll attenuator reservoir via said central liquid reservoir.
• the trim control system comprises at least two forward liquid tanks spaced from each other and each located in the first third, preferably in the first quarter, along a longitudinal axis of the ship.
• two of said forward liquid tanks are spaced along the longitudinal axis of the ship.
• the trim control system comprises at least two aft liquid tanks spaced from each other and each located in the last third, preferably in the last quarter, along the longitudinal axis of the ship.
• two of said rear liquid tanks are spaced along the longitudinal axis of the vessel.
• the vessel further comprises at least one watertight and thermally insulating tank.
• the tank comprises at least one sealing barrier and at least one thermally insulating barrier.
• the tank comprises a main structure comprising a multilayer structure comprising, from the outside inwards, a secondary thermally insulating barrier comprising insulating elements and resting against the supporting structure, a secondary sealing membrane resting against the secondary thermally insulating barrier, a primary thermally insulating barrier comprising insulating elements and resting against the secondary sealing membrane, and a primary sealing membrane intended to be in contact with the liquefied gas contained in the tank.
• a single thermally insulating barrier is placed between a sealing membrane and the supporting structure.
• At least part of the space surrounding the tank is an open space.
• open space means the fact that the volume between two contiguous tanks or between the tank and another part of the ship (these spaces being known to those skilled in the art as cofferdam) are spaces open, or not closed, allowing the circulation, for example, of ambient air from or to said volumes and the adjacent volumes.
• the roll attenuator tank is adjacent to said open space.
• the roll attenuator tank is located forward of the tank, along the longitudinal axis of the ship.
• the tank contains a cold liquid product, in particular liquefied natural gas (LNG) or a liquefied gas.
• LNG liquefied natural gas
• the roll attenuator tank is located above the or a front liquid tank, along a vertical axis of the ship, the vertical axis of the ship being perpendicular to the longitudinal axis and to the transverse axis of the ship.
• the roll attenuator tank is located in the ship so as to be above a waterline of the ship for any cargo weight less than or equal to the maximum cargo weight capacity P TC of the ship.
• attitude control system integrated into the transport vessel of the .
• the ship 1 There is a schematic view of a cargo ship 1 (hereinafter "the ship 1"), in section along the longitudinal axis X-X' of the ship 1.
• the direction from X' to X is the direction of travel of the vessel 1 when it is sailing.
• Vessel 1 is here a transport vessel for liquefied gas, in particular liquefied natural gas (LNG).
• the ship 1 comprises one or more (here, two) tanks 2, which are sealed and thermally insulating.
• the tanks 2 are located forward, along the longitudinal axis X-X' of the vessel 1, of a superstructure 5 provided with a gangway.
• the superstructure 5 is itself located forward of one or more funnels 3 which surmount a machinery 4 arranged under the superstructure 5 and under the funnel(s) 3.
• the ship 1 can more generally be a ship of transport of another liquid product, or even a ship transporting any other type of goods.
• the tanks or the transport holds of the ship 1 are located forward of the superstructure 5.
• Each tank 2 can be of the type comprising a sealing barrier and a thermally insulating barrier, in particular an independent tank, of type A, B or C according to the code of the International Maritime Organization (IMO) or even any equivalent tank.
• each tank 2 may comprise a main structure comprising a multilayer structure comprising, from the outside inwards, a secondary thermally insulating barrier comprising insulating elements and resting against the load-bearing structure, a secondary sealing membrane resting against the secondary thermally insulating barrier, a primary thermally insulating barrier comprising insulating elements and resting against the secondary sealing membrane, and a primary sealing membrane intended to be in contact with the liquefied gas contained in the tank.
• IMO International Maritime Organization
• the load-bearing structure consists of at least part of the walls of the ship 1.
• a single thermally insulating barrier is placed between a sealing membrane and the load-bearing structure.
• Such tanks can for example be produced according to the applicant's Mark III® or NO96® technologies.
• the tanks 2 are preferably surrounded at least in part by cofferdams 6 (cf. ).
• the ship 1 further comprises an attitude control system 10, which will be described in more detail with reference to FIGS. 1A and 1B. It is specified that on the , the liquid tanks of the attitude control system 10 and the tanks 2 are represented empty, the possible fillings of the liquid tanks of the attitude control system and of the tanks 2 being described below.
• the attitude control system 10 is not communicating with the sea, and comprises at least one front tank 20, at least one rear tank 30, a roll attenuator tank 40, and optionally a central tank 50.
• two front tanks 20 are provided.
• the forward tanks 20 are both located in a first quarter of the ship 1 along the longitudinal axis X-X' of the ship 1.
• first quarter is meant the area located between 0% and 25% of the length L of the ship 1 along the X-X' axis, taking 0% at the bow of the ship and going towards the stern of the ship.
• the two front tanks 20 can be located in a first third of the ship, where "first third" designates the zone located between 0% and 33.3% of the length of the ship 1 along the X-X' axis.
• two aft tanks 30 are provided, both located in a last quarter of the ship along the longitudinal axis X-X′ of the ship 1.
• last quarter is meant the zone located between 75% and 100% of the length L of the vessel 1 along axis X-X'.
• the two aft tanks 30 can be located in a last third of the ship, where "last third" designates the area located between 66.7% and 100% of the length of the ship 1 along the axis X-X'.
• the central tank 50 is for its part located in an area comprised between 40% and 60% of the length L of the vessel 1 along the axis X-X'.
• the central reservoir 50 is typically centered on the X-X' axis.
• FIGS. 1A and 2A It has been shown in FIGS. 1A and 2A that the two forward tanks 20 and the two aft tanks 30 are spaced from each other along the axis X-X' of the ship 1.
• two forward tanks 20 and two aft tanks 30 can be spaced from each other in a direction parallel to the transverse axis Y-Y' of the ship 1.
• a large number of other configurations are possible.
• the number of front tanks 20 and rear tanks 30 shown is purely by way of example.
• a single front tank 20 or even three or more front tanks 20 can be provided, and independently, a single rear tank 30 or even three or more rear tanks 30 can be provided, spaced from each other along the axis X-X' and/ or along the Y-Y' axis.
• the roll attenuator tank 40 is located in the first third, preferably in the first quarter, along the axis X-X', of the vessel 1.
• the roll attenuator tank 40 is thus located forward, along the X-X' axis, of the tanks 2 and, where appropriate, of the cofferdams 6.
• the roll attenuator tank 40 can be adjacent to the cofferdam 6 furthest forward along the X-X' axis.
• the roll attenuator tank 40 has a larger dimension which is along the transverse axis Y-Y' of the ship 1.
• this greatest dimension is equal to the greatest width l of the ship 1 along the transverse axis Y-Y'.
• this largest dimension can be equal to between 60% and 100% of l.
• the roll attenuator tank 40 can be above one of the front tanks 20 along the Z-Z' axis.
• the roll attenuator tank 40 is provided with a pair of compartment walls 42.
• the compartment walls 42 are disposed in the volume interior 43 of the roll attenuator tank 40, preferably opposite one another, here parallel to the axis X-X'.
• the partitioning walls 42 extend here only over part of the height of the interior volume 43, they could extend over the entire height of the interior volume 43. In addition, a greater number of partitioning walls 42 can be provided. , or a single partition wall 42 can be provided.
• the geometry of the partitioning walls 42 is intended to make it possible to control the flow of liquid in the interior volume 43.
• the partitioning walls 42 are arranged to slow down a flow of liquid in the roll attenuator tank along the Y-Y' axis, without however completely preventing this flow of liquid.
• the liquid thus remains free to move in the interior volume 43 despite the presence of the compartmentalization walls 42.
• the vessel 1 has been shown subjected to a roll motion 200, this roll motion 200 having a certain periodicity, while the roll attenuator tank 40 is filled with a certain volume 49 of liquid.
• the ship 1 In the left view of the , the ship 1 has been shown at its almost maximum list due to the rolling motion 200. Since the compartmentation walls 42 tend to slow the movement of the liquid in the interior volume 43, they retain the liquid in such a way that the major part of the volume 49 of liquid is still on the side opposite to the side towards which the vessel 1 heeled. The liquid then generates a moment which tends to stabilize the vessel 1. Nevertheless, the liquid begins to move towards the other side of the interior volume 43, first due to the force of gravity generated by the initial inclination, and consequently due to the inertia of the liquid. This displacement of the liquid is represented by the arrow 201.
• the roll movement 200 having a certain periodicity, the configurations shown in the left view and the right view of the occur alternately with this periodicity, and each time, the liquid generates a moment which tends to stabilize the ship 1. It is then understood that the fact of partially filling the interior volume 43 with liquid makes it possible to attenuate the effect of the movement of 200 roll on the ship.
• the time it takes for the liquid to flow into the interior volume 43 depends mainly on the structure of the compartmentation walls 42, and to a lesser extent on the volume of liquid 49 present in the roll attenuator tank 40.
• the design of suitable compartment walls 42 is a common task in trim and trim control of ships, so those skilled in the art will know how to adapt the compartment walls 42 to obtain the desired effect of roll mitigation.
• roll attenuator reservoir 40 will typically be filled with a volume of liquid 49 of between 25% and 75% of the maximum fill volume of roll attenuator reservoir 40.
• a volume of liquid 49 of between 25% and 75% of the maximum fill volume of roll attenuator reservoir 40.
• Those skilled in the art will know how to adjust the volume of liquid 49 in this range, according to the circumstances and in particular according to the weight of the load of the vessel 1, in order to obtain the desired effect of attenuation of the roll. Again, this task is a common task in ship balancing and trim control.
• the trim control system 10 comprises a liquid dispensing device 60 (hereinafter “the dispensing device 60”).
• the distribution device 60 makes it possible to distribute a volume of liquid between these different reservoirs. For example, it is a fixed volume of liquid, in the case where the dispensing device 60 is not intended to receive additional liquid or to evacuate liquid while the vessel 1 is sailing.
• the distribution device 60 controls the way in which the volume of liquid, optionally a fixed volume, is distributed between the reservoirs 20, 30 and 50 and the roll attenuator reservoir 40.
• the attitude control system 10 is not communicating with the sea.
• the liquid that the distribution device 60 distributes is thus not sea water that the ship 1 would load when leaving its port of departure and would release arriving at its port of destination, as is the case with conventional seawater ballasts.
• the filling of the various tanks using the dispensing device 60 can for example be modified during maintenance operations of the ship, for example to complete the filling following losses or to carry out a complete emptying of the tanks and a new filling. , etc.
• the liquid contained in the reservoirs and dispensed by the dispensing device 60 is typically fresh water.
• Fresh water is available in a very large number of infrastructures, and also simplifies the design and maintenance of the attitude control system 10. In the remainder of this description, reference will be made to the case where Fresh water is used in the trim control system 10. However, other liquids can be used. It is preferable that the density of the liquid be approximately equal to 1, for example between 0.95 and 1.05, in order to simplify the design and the use of the attitude control system 10.
• the distribution device 60 comprises a set 68 of pipes placing these different reservoirs in communication, and at least one pump 69 making it possible to set the water in motion between these different reservoirs.
• the hollow arrows on the represent an example of the direction of water circulation in the set 68 of pipes.
• the dispensing device 60 comprises a set of valves to control the arrival or not of water in each of the reservoirs 20, 30, 40 and 50, as well as the filling rate of each of these reservoirs.
• the reservoirs 20, 30, 40 and 50 are respectively provided with pressure equalization orifices 21, 31, 41, 51, which place the interior volume of these reservoirs in communication with the ambient air, and thus make it possible to empty the water contained in these tanks.
• the attitude control system 10 further comprises a control unit 90. As shown in dashed line on the , the control unit 90 is configured to control the dispensing device 60, more specifically to control the at least one pump 69 and each of the valves (not shown) already mentioned above.
• Control unit 90 may be implemented by any combination of suitable hardware and/or software.
• the control unit 90 is typically on board the ship 1, and can be in communication with other equipment on board the ship 1.
• the control unit 90 can comprise or else be in communication with a device for user interface 91 allowing a member of the crew to enter commands to control the operation of the control unit 90, and therefore of the distribution device 60 and thereby of the attitude control system 10.
• a member of the crew can enter, via the user interface device 91, in the control unit 90 a weight of a load of the ship 1, for example at the start of the journey of the ship 1, as well as a weight capacity maximum cargo weight P TC of vessel 1.
• the maximum cargo weight capacity P TC of vessel 1 may be stored in memory in the control unit 90.
• the cargo weight of vessel 1 may be supplied to the control unit 90 by another device, on board ship 1 or not.
• the maximum loading weight capacity P CT of ship 1 is provided by the builder of ship 1.
• the empty weight P v of the ship is provided by the builder of the ship 1, and designates the weight of the ship 1 without any cargo and any other device than those necessary for its operation and possibly a negligible quantity of fuel.
• the total weight P RT of the front tanks 20 and the rear tanks 30, when completely filled with a liquid of density equal to 1, represents between 2% and 8%, preferably between 3% and 6 %, of the empty weight P v of vessel 1.
• the total weight P ART of the roll attenuator tank 40 when the latter is filled with a liquid of density equal to 1, represents between 1% and 4%, preferably between 2% and 4% , the empty weight P v of the ship.
• FIGS. 5A and 5B a first case has been shown where the weight of the ship's load 1 is very close to the maximum load weight capacity P TC .
• the filling level of tanks 2 is very close to the maximum authorized filling level of tanks 2.
• the roll attenuator tank 40 is not filled with water and is therefore not in operation.
• the volume of water contained in the attitude control system 10 is therefore distributed between the front tanks 20, the rear tanks 30 and the central tank 50.
• the volume of water is distributed between these tanks so that the draft at the fore bow of the ship 1, denoted below Tf, is equal or substantially equal to the draft at the stern of the ship 1, denoted below Ta.
• the drafts Ta and Tf are measured, as is well known in the field of ships, from the waterline of the ship or relative to the surface of the sea, which bears the reference 100 in the drawings.
• the roll attenuator tank 40 is partially filled with water, more precisely between 25% and 75% of its maximum filling volume as mentioned above.
• the control unit 90 can control the distribution device 60 so as to switch from the distribution of the volume of water which is represented in the to the distribution of the volume of water which is represented on the . More concretely, in response to a roll attenuation command, the control unit 90 controls the distribution device 60 to transfer water to the roll attenuator tank 40 until the latter is partially filled. of water as just mentioned.
• the roll attenuation command can for example be provided to the control unit 60 by a member of the crew.
• the distribution device 60 can take water only from the rear tanks 30, only from the front tanks 20, or even only from the central tank 50.
• the distribution device 60 it is preferable for the distribution device 60 to take water from both the rear reservoirs 30 and the front reservoirs 20, or even both from the rear reservoirs 30 and from the front reservoirs 20 and from the central reservoir 50, in order to avoid excessively modifying the trim of the ship 1.
• the command described above in connection with FIGS. 5A and 5B can be performed when the weight of the ship's load 1 is greater than or equal to 0.8*P TC . More concretely, the control unit 90 obtains the cargo weight of the ship 1 and obtains the maximum cargo weight capacity P TC as described above, then controls the distribution device 60 as described above. above when the weight of ship 1's load is greater than or equal to 0.8*P TC .
• FIGS. 6A and 6B a second case has been shown where the weight of the ship's load 1 is small compared to P TC .
• the level of filling of tanks 2 is low. This situation can occur in particular when the ship 1 is transporting LNG in the tanks 2. In such a situation, it is indeed essential to maintain a minimum level of LNG in the tanks 2, also called "liquid heel", as is known.
• the front tanks 20 are more filled with water in the configuration of the only in the configuration of the ; this in order to counterbalance the weight of the equipment located at the rear of the ship 1, in particular its machinery 4, its funnel(s) 3, and its superstructure 5, and to prevent the draft at the bow front of the ship 1 Tf is too low.
• the roll attenuator tank 40 is partially filled with water, more precisely between 25% and 75% of its maximum filling volume as mentioned above.
• the control unit 90 can control the distribution device 60 so as to switch from the distribution of the volume of water which is represented in the to the distribution of the volume of water which is represented on the . More concretely, in response to the roll attenuation command, the control unit 90 controls the distribution device 60 to transfer water to the roll attenuator tank 40 until the latter is partially filled. of water as just mentioned. In principle, to fill the roll attenuator tank 40, the distribution device 60 can take water both from the rear tanks 30 and from the front tanks 20, or even both from the rear tanks 30 and from the front tanks 20 and in the central tank 50.
• the distribution device 60 takes water only from the front tanks 20, in order to avoid transferring even more water to the front of the vessel 1 and therefore avoid increasing the draft at the bow of vessel 1 Tf. It is in fact preferable not to increase Tf so as not to create an excessive sinking of the front bow 8 of the ship 1 in the water, which could be harmful to the navigation properties of the ship 1.
• the command described above in relation to FIGS. 6A and 6B can be carried out when the weight of the ship's load 1 is less than or equal to 0.2*P TC . More concretely, the control unit 90 obtains the weight of the ship's cargo 1 and obtains P TC as described above, then controls the distribution device 60 in the manner described above when the weight of the cargo of vessel 1 is less than or equal to 0.2*P TC .
• FIGS. 7A and 7B a third case has been shown where the weight of the ship's load 1 is intermediate between those shown in FIGS. 5A-5B and 6A-6B. This situation can occur in particular when the tanks 2 are partially filled with LNG or with another liquid product.
• the roll attenuator tank 40 is partially filled with water, more precisely between 25% and 75% of its maximum filling volume as mentioned above.
• the control unit 90 can control the distribution device 60 so as to switch from the distribution of the volume of water which is represented in the to the distribution of the volume of water which is represented on the . More concretely, in response to the roll attenuation command, the control unit 90 controls the distribution device 60 to transfer water to the roll attenuator tank 40 until the latter is partially filled. of water as just mentioned. In principle, to fill the roll attenuator tank 40, the distribution device 60 can take water only from the rear tanks 30, only from the front tanks 20, or even only from the central tank 50.
• the distribution device 60 it is preferable for the distribution device 60 to take water from both the rear reservoirs 30 and the front reservoirs 20, or even both from the rear reservoirs 30 and from the front reservoirs 20 and from the central reservoir 50, in order to avoid modifying the trim of vessel 1 or at the very least increasing the draft at the bow of vessel 1 Tf.
• the command described above in relation to FIGS. 7A and 7B can be carried out when the weight of the ship's load 1 has a value between 0.2*P TC and 0.8*P TC , these lower and upper bounds being excluded. More concretely, the control unit 90 obtains the cargo weight of the ship 1 and obtains the maximum cargo weight capacity P TC as described above, then controls the distribution device 60 as described above. above when the weight of the ship's load 1 is strictly between 0.2*P TC and 0.8*P TC .
• control unit 90 can as a variant perform a control of the distribution device 60 independently of these quantities, for example only according to a command from a member of the crew.
• the roll attenuator tank 40 is located in the ship 1 so as to be above the waterline 100 of the ship, whatever the weight of the load of the ship 1 (as long as this weight is lower or equal to P TC ).
• control unit 90 can be produced in different forms, in a unitary or distributed manner, by means of hardware and/or software components.
• Usable hardware components are specific integrated circuits ASIC, programmable logic networks FPGA or microprocessors.
• Software components can be written in different programming languages, for example C, C++, Java (registered trademark) or VHDL. This list is not exhaustive.
• the control unit 90 may also be absent or less sophisticated.
• the crew can directly or indirectly control the valves and/or pumps of the distribution device 60 to implement the following uses:
• transfer liquid to the roll attenuator tank 40 from the front liquid tank 20 and/or the liquid tank 30, preferably from the forward liquid tank 20 and the aft liquid tank 30 and/or so as not to increase the draft Tf at the bow of the ship 1.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)

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Publications (1)

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• 2021
  • 2021-09-30 FR FR2110347A patent/FR3127465A1/fr active Pending
• 2022
  • 2022-09-30 EP EP22793567.3A patent/EP4408732A1/de active Pending
  • 2022-09-30 WO PCT/EP2022/077370 patent/WO2023052626A1/fr not_active Ceased
  • 2022-09-30 CN CN202280066385.4A patent/CN118043256A/zh active Pending
  • 2022-09-30 JP JP2024519534A patent/JP2024536216A/ja active Pending
  • 2022-09-30 US US18/696,254 patent/US20240391565A1/en active Pending
  • 2022-09-30 KR KR1020247012700A patent/KR20240074796A/ko active Pending

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