GB2150903A

GB2150903A - Method and assembly for launching or retrieving a lifeboat

Info

Publication number: GB2150903A
Application number: GB08430466A
Authority: GB
Inventors: Per Berger
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-12-07
Filing date: 1984-12-03
Publication date: 1985-07-10
Also published as: FR2556309A1; GB2150903B; DK582784A; DK582784D0; GB8430466D0; SU1373312A3

Abstract

An assembly for launching or retrieving a lifeboat (12), pick-up boat or the like from a ship (10) or a stationary installation includes a boat dock (1) having float bodies (2,3). Control wires (17) extending down to the sea from the ship (10) or the stationary installation cooperate with guide means (6,7) on the boat dock (1) to control the dock during lowering and hoisting. The control wires (17) have weights (18) at their free ends, which hold the wires taut at all times. The weights are lowered while suspended from the control wires and are submersed in the water, or may optionally rest on the sea bed, in which case the control wires are tensioned by means of winches (16) on board the ship (10) or on the stationary installation. In this manner, the boat dock (1) can float in the sea and follow the wave movements, while at the same time it is stabilized due to the control of the wires (17). There is a coupling means (5) on the boat dock (1) which engages with a coupling means (21) on the boat (12) when the boat is in the dock. <IMAGE>

Description

SPECIFICATION Method and assembly for launching or retrieving a lifeboat This invention relates to a method of launching or retrieving a lifeboat, pick-up boat or the like from a ship or a stationary installation.

The invention also relates to an assembly for launching or retrieving a lifeboat, pick-up boat or the like from a ship or a stationary installation, comprising a boat dock with floats, means for lowering and raising the boat dock, and means for controlling/ stabilizing the boat dock in relation to the ship or stationary installation.

The present invention has arisen in response to the need for a way to launch a lifeboat or the like and to retrieve it from the sea without risking the lifeboat being cast against the side of the ship or the stationary installation, which may be the sid of a quay, a marine installation, an offshore platform or the like, where it might be crushed. The invention is especially needed for lifesaving operations in which a lifeboat has to be launched for retrieving people from the sea in bad weather.

Lifeboats are normally suspended from various types of davits or the like. The boats are usually attached to wires running from winches on board the ship or stationary installation. In bad weather with heavy seas, it is both dangerous and difficult to launch a boat using such equipment. The lifeboat usually hangs from two hooks which must be released in a quick and safe manner. A wave surging against a side of a ship or the side of a stationary installation will often build up, exerting powerful vertical forces and rising higher than a wave otherwise would. A boat lying close to the side of the ship or installation is thus subjected to larger movements than if it were positioned a distance away from the side of the ship.It is also a fact that the sea does not have to be especially heavy before it becomes both difficult and sometimes utterly impossible to launch or retrieve a lifeboat.

According to the present invention, there is provided a method of launching or retrieving a lifeboat, pick-up boat and the like from a ship or a stationary installation, including lowering a boat dock down to the sea under the control of one or more control lines which lead from a crane winch on the ship or the stationary installation down to the sea and each of which is held taut by a weight attached to the free end of the line which is intended to be submersed in the sea, whereby the boat dock is brought into a position in which it floats in the sea and is controlled by the line or lines, and thereafter allowing a boat to be launched to leave the boat dock, or driving a boat to be retrieved into the boat dock and raising the boat dock together with the boat.

A preferred method embodying the invention includes releasing cooperating coupling means on the boat dock and boat to allow a boat be launched to leave the boat dock, or engaging the co-operating coupling means after driving a boat to be retrieved into the boat dock to secure the boat dock and boat together.

Control and lowering/raising of the boat dock can be combined. Thus, the boat dock may be lowered while suspended from the control lines, resting on the weights, and can be raised in the same manner.

Alternately, the boat dock can be lowered by a separate line which is subsequently released automatically. The control lines can be used for hoisting the boat on board, with the boat dock in that case resting on the weights, or the boat dock can be hoisted up with its own line. In the latter case, it is an advantage to let the line for the boat dock remain fastened to the boat dock at all times, and optionally to connect it to a self-tensioning winch.

If necessary, the weights at the end of the lines can be lowered to rest on the sea bed, and the lines are then tensioned as necessary by means of the crane winch/winches.

The present invention also provides an assembly for launching or retrieving a lifeboat, pick-up boat or the like from a ship or a stationary installation, comprising a boat dock having float bodies, means for lowering and raising the boat dock, and means for controlling/stabilizing the boat dock in relation to the ship or the stationary installation, in which assembly the means for controlling/stabilizing the boat dock comprise one or several control lines which extend from a crane winch to a weight attached to the free end of each line, and guide means on the boat dock for guidance of the lines.

Preferably, the assembly includes co-operating coupling means on the boat dock and the boat for securing the boat dock and boat together.

This assembly permits the execution of the method according to the invention and enables the boat dock to be controlled and stabilized, which permits the boat dock to float with controlled freedom in the sea, i.e., to move up and down with the waves without being thrown against the side of the ship or stationary installation.

In a practical embodiment, the weights may be formed as a boat cradle, which will hold the lines taut as the cradle is being lowered. The boat rests in the cradle during lowering and is released when the cradle is submersed in the sea. During retrieval, the boat is positioned above the submersed cradle and the cradle is then hoisted up, carrying the boat together with the boat dock up to the ship.

The boat dock is preferably formed with float bodies in the form of two pontoons extending substantially parallel to one another and, in use, to the sides of the boat, the portions being interconnected by a portal frame on which coupling means of the dock is mounted. The boat is guided in between the pontoons, which constitute a part of the boat dock and secured to the dock by means of the co-operating coupling means on the dock and boat prior to being hoisted on board. During launching, the boat is secured to the boat dock in position between the pantoons, i.e., in the same position as during retrieval, and as soon as the boat dock has been lowered to float in the sea and stabilized by the control lines and associated weights, the coupling means is released and the boat can move off.

The coupling means on the boat dock is preferably formed with a downwardly, forwardly and rearward ly open slot for receiving a ball, the slot also comprising a catch mechanism for retaining the ball in the slot. The coupling means on board the lifeboat comprises a ball disposed on the end of a rod or the like. When the boat is moved into the boat dock, the ball will enter the slot and be secured within the slot by the catch mechanism. The boat will be secured to the dock in a similar manner during lowering. As soon as the boat has reached the sea, the catch mechanism can be released and the ball will slip out of the slot when the boat leaves the dock.

In order that the invention may be readily understood, embodiments thereof will now be described by way of example, with reference to the accompanying drawings, in which: Figure lisa schematic drawing of one possible embodiment of a lifeboat launching/retrieving assembly according to the invention; Figure 2 shows a second possible embodiment of a lifeboat launching/retrieving assembly according to the invention; Figure 3 shows the assembly of Figure 2 without a boat in the boat dock; Figure 4 shows the boat dock of Figure 3 in side view; Figure shows a coupling means associated with the boat docks of both Figures 1 and 2; and Figure 6 shows the coupling means in cross section, both Figures 5 and 6 being drawn on an enlarged scale, compared to the other Figures.

In both of the embodiments illustrated in the drawings a boat dock 1 is utilized which essentially comprises two pontoons 2, 3. The pontoons 2, 3 have vertical through bores or similar guide means 6,7 and 8, 9, respectively. The boat dock shown in Figure 1 utilizes only the guides 6,7 in one potoon 3.

The pontoons 2 can optionally be made without such through holes or bores, since they are not utilized in the embodiment illustrated in Figure 1, but the guide holes in both pontoons are use in the embodiment shown in Figure 2.

A ship or a stationary installation 10 is provided with an outwardly projecting platform 11. The platform 11 has a substantially rectangular opening (not visible in the drawings) adapted to the configuration of the boat dock 1 and the boat 12 which is lowered and raised by means of the dock 1. A crane 13 is placed on the platform 11. A self-extensioning winch 14 is arranged on the jib of the crane, and a guide sheave 15 is suspended from the jib of the crane. One or more winches 16 are positioned underneath the platform ,1 at the foot of the crane 13.

A line in the form of a wire 17 extends from the winch 16 up to the guide sheave 15, passing around the sheave and then being guided downwardly to pass through the guide hole 6 in the pontoons 3. A weight 18 hangs on the end of the wire 17. In similar manner, a second wire line (not shown) is guided either from the same winch 16 or from a similar winch, up and around a second sheave 15 and down through the guide hole 7 in the pontoon 3, the second wire also being provided with a weight corresponding to the weight 18.

A line in the form of a wire 19 extends from the automatic-tension which 14 down to the boat dock 1, where it is fastened to the dock 1, in this case to its portal frame 4 at the coupling means 5, which constitutes a part of the frame.

The coupling means 5 may be seen in Figures 4, 5 and 6. It is formed as a body having a downwardly, forwardly and rearwardly open slot 20 for receiving a ball 21. The ball 21 sits on the end of a rod 22 that is fastened to the boat in a suitable manner. The ball 21 can be secured within the slot 20 by means of two spring-loaded catch members 23, 24 which will automatically secure the ball when it is guided into the slot. To unlock the coupling, the catch members 23, 24 are retracted in opposition to the spring force (the actuation of this is not illustrated), and the ball is released.

The assembly shown in Figure 1, is used as follows: The boat dock 1 with the boat 12 firmly secured thereto is placed in the opening in the platform 11 and secured there in a manner not illustrated herein; alternatively, it may be merely held there in suspension from the wire 19. To lower the boat 12, the winch or winches 16 are actuated to lower the wire 17, the weights 18 at the end of the wire holding the wire taut. The wires 17 are played out until the weights 18 are submersed in the sea; optionally, the weights can be lowered all the way to the sea bed and the wires 17 are then tensioned in a suitable manner by means of the winch 16, which may be a self-tensioning type winch. Then, using the winch 14 and associated wire 19, the boat dock 1 with the boat 12 can be lowered.During this operation, the pontoon 3 is controlled by the wire 17 which passes through the guide holes 6,7 in the pontoon. When the boat dock has reached the surface and floats in the sea, it will be able to move with the wave surge, but it will at all times be under the stabilizing control of the wires 17. When judged appropriate, the coupling means 20, 21, 23, 24 can be released and the boat can move away from the dock.

To retrieve the boat, the boat is driven into the boat dock 1, which may either still lie in the sea or which must first be lowered as described above. The ball coupling 20, 21 is engaged, and the boat dock and boat can then be hoisted up as a unit, under the stabilizing control of the wires 17.

The assembly illustrated in Figures 2,3 and 4 differs from the first embodiment in that four control wires 25, 26, 27 and 28 are utilized. Each control wire travels up to a separate winch 29 on the crane. The crane 13, the ship or permanent installation 10 and the platform 11 are substantially the same as those in Figure 1, and the same reference numerals are used.

The control wires 25-28 are connected in pairs to a common weight, 30 and 31, respectively, i.e., the control wires 25 and 27 are both connected to one weight 30, and the wires 26 and 28 to another weight 31. These weights are identical and are formed as V-shaped cradle members, as seen in Figures 2 and 3. The two cradle members 30, 31 can optionally be connected to each other, e.g. by one or two longitudinal beams (not shown).

When using this assembly, the boat dock 1 and boat 12 are placed in the opening in the platform 11 and the weights 30, 31 are lowered. The boat dock and boat 12 can be lowered simulataneouslywith the weights, resting in the boat cradle 30, 31, or the boat dock 1 can be lowered by means of a separate wire (not shown) connected to the locking means 5, as in Figure 1, afterthe control wires have been lowered into position and tensioned by means of the submersed weights 30, 31. A self-releasing connection may be provided between the said notillustrated wire and the boat dock 1,5, and as soon as the boat dock 1 is floating in the water, the boat 12 can be released from the dock as described above.

For retrieving the boat, the weights are lowered and the control wires held taut, while the boat dock 1 floats in the sea, controlled by the wires. The boat 12 is driven into the dock and coupled thereto, and the boat dock with the boat 12 is raised by winching up the control wires 25, 26, 27 and 28. This embodiment could also be modified so that the boat dock 1 would at all times be connected by the wire to a selftensioning winch in the crane, as in Figure 1.

The described embodiments of the invention thus provide a method and assembly for launching and retrieving a lifeboat which operate with the aid of wires which hold the boat dock in position and prevent it from capsizing. The wires are held taut by means of weights which lie in the sea, or optionally rest on the sea bed. In the latter case the wires are connected to self-tensioning winches or similar devices on the crane. The method and assembly are simple and reliable and provide a high degree of safety in the exercise of a normally dangerous operation.

Claims

1. A method of launching or retrieving a lifeboat, pick-up boat and the like from a ship or a stationary installation, including lowering a boat dock down to the sea under the control of one or more control lines which lead from a crane winch on the ship or the stationary installation down to the sea and each of which is held taut by a weight attached to the free end of the line which is intended to be submersed in the sea, whereby the boat dock is brought into a position in which if floats in the sea and is controlled by the line or lines, and thereafter allowing a boat to be launched to leave the boat dock, or driving a boat to be retrieved into the boat dock and raising the boat dock together with the boat.

2. A method according to claim 1, including releasing co-operating coupling means on the boat dock and boat to allow a boat to be launched to leave the boat dock, or engaging the co-operating coupling means after driving a boat to be retrieved into the boat dock to secure the boat dock and boat together.

3. A method according to claim 1 or 2 wherein the boat dock is raised with the aid of weightsupporting control lines.

4. A method according to any one of claims 1 to 3 including submersing the weights so that they rest on the sea bed, and keeping the control lines under the desired tension by means of the crane winches.

5. An assembly for launching or retrieving a lifeboat, pick-up boat or the like from a ship or a stationary installation, comprising a boat dock having float bodies, means for lowering and raising the boat dock, and means for controlling/stabilizing the boat dock in relation to the ship or the stationary installation, in which assembly the means for controlling/stabilizing the boat dock comprise one or several control lines which extend from a crane winch to a weight attached to the free end of each line, and guide means on the boat dock for guidance of the lines.

6. An assembly according to claim 5, including co-operating coupling means on the boat dock and the boat for securing the boat dock and boat together.

7. An assembly according to claim 6 in which the boat dock is formed with float bodies in the form of two pontoons extending substantially parallel to one another, the pontoons being connected to each other via a portal frame on which the coupling means of the boat dock is mounted.

8. An assembly according to claim 6 or 7 in which the coupling means on the boat dock comprises a downwardly, forwardly and rearwardly open slot for receiving a ball, and catch means for securing the ball in the slot, and the coupling means on board the boat comprises a ball disposed on the end of a rod orthe like.

9. An assembly according to any one of claims 5 to 8, in which the weights are formed as a boat cradle.

10. A method of launching or retrieving a lifeboat, pick-up boat of the like, substantially as hereinbefore described with reference to to the accompanying drawings.

11. An assembly for launching or retrieving a lifeboat, pick-up boat or the like, substantially as hereinbefore described with reference to the accompanying drawings.

12. Any novel feature or combination of features herein described.