This application is the U.S. national phase of International Application No. PCT/EP2020/060257 filed Apr. 9, 2020 which designated the U.S. and claims priority to FR Patent Application No. 1904125 filed Apr. 17, 2019, the entire contents of each of which are hereby incorporated by reference.
The present invention relates to the field of launching and recovery of unsinkable marine craft by a vessel.
It relates more particularly to the recovery of vessels of small dimensions from a mother vessel or carrier ship. This includes coasters, tenders, exploration vessels, whether piloted, remotely operated or autonomous (surface drone). In a military ship, the set of these small craft on board the carrier ship is called the davit craft.
A preferential application of the invention is found in the launching and recovery of semi-rigid boats, commonly known as RHIBs for “rigid-hulled inflatable boat”.
The launching of a marine craft by a ship, called mother vessel, carrier ship, or else mothership, as well as its recovery, are carried out in the state of the art by virtue of various devices.
It is known for example to use davits, of various types, which make it possible to deposit a marine craft in the water or lift it from the surface of the water, overhanging the hull of the mother vessel. Davits are particularly suitable for the launching and recovery of surface craft.
Document CN 104,015,886 presents an example of a device with davits.
Davits are reliable devices in widespread use. However, the devices with davits known in the state of the art have a certain number of drawbacks.
Systems with davits are not generally suitable for recoveries of autonomous surface marine craft. The devices with davits that allow recoveries of autonomous marine craft or without intervention by the personnel on board the marine craft are dedicated devices for a specific type of craft and are complex and heavy. These devices are difficult to adapt to ships that are not originally equipped with them.
Moreover, the use of simply constituted systems with davits is complex or even impossible in a moderate sea with significant swell. Sea state is commonly described according to the Douglas scale, which defines sea state in nine value classes. Davits known in the state of the art can at best be used up to sea state 3, i.e. slight.
The invention aims to propose a system of the davit type for the launching and especially the recovery of a surface marine craft, allowing the recovery of craft that are autonomous, remotely-operated, or crewed but with little (or no) involvement of the personnel on board the craft during its recovery, and capable of being utilized in a moderate sea.
Thus, the invention relates to a system for the recovery of a surface marine craft by a carrier ship, said system comprising:
a) a lifting device intended to equip the carrier ship and which comprises:
b) a receiving device suitable for cooperating with the lifting device and intended to equip the marine craft, the receiving device comprising:
The invention is based on a conventional device with a davit (or a device with a similar configuration) which limits its cost, facilitates its implementation, and allows the adaptation of pre-existing systems of the davit type. The utilization of a forward module borne by the surface marine craft to be recovered makes it possible to automate the steps intended to receive the guide and lifting cables at said surface marine craft.
The lifting cable can comprise an end portion fastened detachably to the guide cable so as to facilitate jointly receiving said guide cable and lifting cable in the opening of the forward module.
The system can comprise a winch on which the towing cable is wound so as to vary the length of the towing cable outside the hull of the carrier ship.
The anchor can comprise an arm by way of part by which it is fastened to the forward module, said arm being substantially oriented towards the surface of the water when the anchor is suspended by the guide cable, in the absence of other constraints, and submerged.
In an embodiment, the receiving device also comprises two guide bars articulated on the forward module, said bars being able to pivot from a folded position to a deployed position in which they form a guide, converging towards said forward module.
The handle and the lifting support preferably have corresponding shapes, such that the handle is immobilized with respect to the lifting support when the lifting cable, which was fastened to the handle via its connection interface, is tensioned.
A tension roller can be provided close to the lifting support, the tension roller comprising a handling cable connected to the handle, take-up of the handling cable making it possible to bring the handle from the forward module to the lifting support.
The invention also relates to an ensemble comprising a carrier ship and a surface marine craft comprising a recovery system such as previously described, the lifting device equipping the carrier ship and the receiving device equipping the marine craft. The marine craft can be a small craft of the semi-rigid hull type.
Finally, the invention relates to a method for the recovery of a marine craft equipped with a receiving device, by a carrier ship equipped with a lifting device, said receiving device and lifting device forming a recovery system as described above, said method comprising the steps of:
Other features and advantages of the invention will become apparent from the following description.
In the attached drawings, given by way of non-limitative examples:
The marine craft 4 shown here is a boat with a semi-rigid hull, capable of forming part of the davit craft of the carrier ship 1.
In order to launch the marine craft 4 and recover it, the carrier ship comprises a davit 5, the end of which can be positioned overhanging the hull 6 of the carrier ship. This makes it possible to lift or lower the marine craft 4 along the hull 6, by virtue of a lifting cable 7 connected to the davit 5. The lifting cable can in particular be unwound outside the carrier ship 1 to lower the marine craft 4 or wound in the carrier ship 1 so as to lift the marine craft 4, for example using a pulley hoist.
The lifting cable 7 is connected for this purpose to a lifting point of the marine craft, which is formed by an element suitable for bearing the weight of the marine craft and its occupants, if applicable, and which is positioned at a lifting point 8 making it possible to suspend the marine craft on an even keel, substantially flat. The lifting point is thus substantially in the vertical axis of the centre of mass of the marine craft. During lifting of the marine craft, one or more boat ropes make it possible to control the orientation of the marine craft suspended from the davit.
Of course, the lifting point can be formed based on a set of straps or ropes connected at several points of the marine craft, and the invention that is described hereinafter is applicable to such a configuration. For the sake of simplicity, it is assumed that the lifting point is a single point, forming part of the marine craft 4.
Similarly, both the prior art and a system according to the invention are shown in the present document with reference to a system comprising a single davit, but it is clear that the invention can be applied to a system with multiple arms.
The device shown in
Moreover, the invention is described hereinafter on the basis of a lifting device comprising a davit per se. The invention can more generally utilize a lifting means “of the davit type”, i.e. a davit per se or an equivalent lifting device, overhanging the hull of a carrier ship, for example a crane in a similar configuration to that of a davit.
The system in
The length of the guide cable 10 can be fixed or adjustable. A guide cable 10 of adjustable length, for example using an on-board winch in the carrier ship 1, makes it possible for example to adapt the length of said guide cable 10 to the level of sea swell. The anchor 11 can consist of a massive element, for example made from metal. The anchor 11 can comprise hydrodynamic planes that orient the anchor in a predefined position when the carrier ship 1 moves ahead.
The free end of the lifting cable 7 is fastened detachably to the anchor 11. Moreover, an end portion of said lifting cable 7 is fastened detachably to the guide cable 10, so that, from the anchor 11 to a given point of the guide cable, situated between the anchor 11 and the boat hook pole 9, the lifting cable 7 follows the guide cable 10. On this portion, the lifting cable 7 and the guide cable 10 thus form only a single elongated assembly.
The lifting device also comprises a towing cable 12. The towing cable 12, equivalent to a boat rope used in the known devices, is connected to the carrier ship 1 at a point of the hull 6 situated forward of the davit 5 and forward of the boat hook pole 9.
The concepts of forward and aft are understood, in the whole of the present document, in the usual manner, i.e. along the axis linking the prow of a boat and corresponding to “forward”, to the stern or to the transom of the boat and corresponding to “aft”. The towing cable 12, by its orientation makes it possible, when it is connected to a surface marine craft that must be recovered by the carrier ship 1, to tow the marine craft and to hold it longitudinally in position with respect to the carrier ship 1.
The system in
The receiving device comprises a forward module 13, installed on the bow of the surface marine craft 4. The forward module 13, the composition of which is detailed hereinafter, can be called “rostrum”, as it extends partially overhanging the prow of the marine craft 4.
By “variable length of a cable” is meant that the free part of the cable is variable in length, typically the length of the lifting cable 7 between the davit 5 and its free end, the length of the guide cable between the boat hook pole 9 and the anchor 11, the length of the traction cable 12 between the hull 6 of the carrier ship and the anchor 11.
The lifting device in
The guide cable 10 can be equipped with a float or a buoy 16.
A recovery sequence of the marine craft 4, typically corresponding to the marine craft in
In the state shown in
Once the marine craft 4 has arrived close to the lifting device, as shown in
In the retracted position, also called “passive” position, the bars 17 can substantially hug the shape of the (rigid or inflatable) hull of the marine craft 4. In the deployed position, also called “active” position, the bars 17 are oriented substantially in a V-shape with respect to one another, preferably symmetrically with respect to a longitudinal plane of symmetry of the marine craft (if the marine craft is symmetrical). The bars 17 extend overhanging the bow of the marine craft 4 substantially horizontally (parallel to the surface of the water), and form an angle between them in order to allow the recovery and guiding towards the forward module 13 of any substantially vertical cable or element entering between them.
Of course, other configurations of the forward module can be used, according to various variant embodiments of the invention, so as to form a convergent guide, in particular with fixed or mobile bars, in planes other than the horizontal plane. The bars 17 can be incurved (for example to hug the shape of the forward hull of the marine craft). The means allowing a cable or rope to be received at the level of the prow of the marine craft can have shapes other than two bars; it can be in one piece or otherwise be formed from several elements capable of unfolding to form a guide. The movement of the bars 17, or of any other means allowing a cable to receive at the bow of the marine craft, can be automatic (motorized) or manual.
In the example shown, the marine craft 4 is then manoeuvred to bring the guide cable 10 facing the branches 17, within the angle that they form.
In position a, the guide bars 17 come into abutment against the guide cable 10 and the lifting cable 7, due to the forward movement of the marine craft 4. By converging towards the forward module 13, the bars 17 guide the guide cable 10 and the lifting cable 7 towards a trigger 18, on which the guide cable 10 and the lifting cable 7 press so as to actuate it in rotation (position b in
The guide cable 10 and the lifting cable 7 then enter an opening 19 formed in the forward module 13. Once the trigger 18 is free from the guide cable 10 and the lifting cable 7, it closes again so as to prevent the guide cable 10 and the lifting cable 7 from coming out of the opening 19. The guide cable 10 and the lifting cable 7 can nevertheless move freely in vertical translation in the opening 19. This position corresponds to the position c shown in
At this stage, the traction cable is loose, and applies no significant force on the marine craft 4.
In the step shown in
Astern movement of the marine craft can be achieved by decreasing speed, to a speed lower than that of the carrier boat, for example.
The system shown here comprises a guide cable of fixed length. As an alternative or in addition, the guide cable can be of variable length, for example adjustable with the use of a winch, to cause the guide cable to be raised into the opening 19 of the forward module 13.
In the step shown in
The part of the anchor 11 to which the connecting interface 14 of the lifting cable is connected, which here has the shape of a hook, is introduced into the opening 19 of the forward module 13. This positions the hook facing a handle 21, shown in
The connecting interface is then engaged on said handle 21, and hooks onto the latter.
Of course, any other connection interface configuration can be envisaged, provided that said connection interface is configured so as to connect to the handle 21 during fastening of the anchor 11 to the forward module 13.
The winch of the davit 5 is actuated, which reduces the length of the lifting cable 7. The shortening of the lifting cable 7 starts to cause its separation from the guide cable 10, as shown in
The connection means 15 progressively release the lifting cable 7 until it is completely separated from the guide cable 10.
The handle 21 is furthermore connected by a cable to a winch situated close to the lifting point 8 of the marine craft 4.
Traction of the lifting cable 7 on the handle 21 and/or the actuation of the winch situated close to the lifting point 8 releases the handle 21 of the forward module 13.
Take-up of the cable connecting the handle to the winch situated close to the lifting point 8 brings said handle 21 towards the lifting point 8. This step is shown in
In this situation, the towing cable 12 ensures that the marine craft is held longitudinally with respect to the carrier boat. The guide cable 10 essentially ensures that it is held laterally, at its prow level.
When the handle reaches the lifting point 8, it is fastened to a lifting support that is arranged at this point, automatically (for example as explained with reference to
The marine craft 4 can then be lifted, hoisted out of the water by the lifting cable 7. More precisely, the connection interface 14 (for example in the form of a hook) of the lifting cable is engaged with the handle 21 which is fastened to the lifting support. This step is shown in
In
In
In
In
As shown in
The system thus developed in the invention allows the recovery of a surface marine craft from a carrier boat. It can be used both for piloted marine craft and for crewless remotely operated or autonomous marine craft. Moreover, recovery of the marine craft can be carried out in a moderate sea, typically up to a sea state of level 4 or 5 according to the Douglas scale. The invention is based on a lifting means of the conventional davit type, which limits its cost, facilitates its utilization, and makes it possible to adapt the system to a pre-existing davit.
Number | Date | Country | Kind |
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1904125 | Apr 2019 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/060257 | 4/9/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2020/212269 | 10/22/2020 | WO | A |
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103183113 | Jul 2013 | CN |
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Entry |
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International Search Report for PCT/EP2020/060257 dated May 8, 2020, 7 pages. |
Written Opinion of the ISA for PCT/EP2020/060257 dated May 8, 2020, 6 pages. |
Number | Date | Country | |
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20220212760 A1 | Jul 2022 | US |