GB2081212A - A device for launching and recovering boats from vessels and fixed structures - Google Patents

Abstract

A platform 1 on which a boat 2 can be stored operates as a retractable launching/recovery ramp. The platform 1 can slide and tilt on a fulcrum 5 adjacent the edge of a vessel or fixed structure 4. An upstanding strut 6 is pivoted at its upper end 6a to the platform 1 at 8, and is pivotally supported at its lower end at 7 by the vessel or structure 4. The strut 6 controls movement of the platform 1 as it is extended out from the edge of the vessel or structure 4, and it supports the platform 1 when the latter is in the extended position. <IMAGE>

Description

SPECIFICATION A device for launching and recovering boats from vessels and fixed structures This invention relates to devices for launching and recovering boats from vessels and fixed structures.

Current systems for launching and recovering boats either use a davit system or a stern ramp which is built into the hull of the motor vessel.

Launching and recovering from a davit often entails stopping or slowing the mother vessel whilst a stern ramp can allow the boat to be launched and recovered at speed. However, current stern ramps entail the construction of a special launching ramp within the hull of the mother vessel, and the object of the invention is to provide a system to overcome this disadvantage by allowing a ramp to be fitted with only minor modification to an existing vessel, and to operate by being capable of extension when required and of being retracted for stowage when not in use.

In essence a device in accordance with the invention is a platform on which the boat can be stored and which operates as a retractible launching/recovery ramp. Specifically, a device in accordance with the invention comprises a platform on which a boat can be stored and which can slide and tilt on a fulcrum arrangement adjacent the edge of a vessel or structure, and an upstanding strut pivoted at its upper end to the platform adjacent the outboard end thereof and pivotally supported at its lower end by the vessel or structure, whereby the strut controls the movement of the outboard end of the platform as it is extended to the operative position and supports the platform in the extended position.

Movement of the platform can be controlled and/or assisted by hand, cable, hydraulic cylinder or other means. Such means can be combined with a system for hoisting the boat on to the platform, or be separate therefrom. Normally the boat will be attached to the platform when in the stowed position so that it moves with the platform to the launching position, when it can be released and floated off. The reverse procedure can be adopted for recovery.

If the length of the platform is deemed to be too short for safe launch and recovery it may be extendable at one end, or at both ends. Thus a folding extension may be provided at the outboard end which automatically extends as the platform is extended out from the stowed position, and which forms a safety rail when the platform is stowed.

Alternatively, or additionally, a telescopic extension may be provided at the inboard end of the platform.

When the device is mounted at the stern of a mother vessel the effective height of the transom thereof may allow use of only a short strut which would provide too steep an extended ramp angle.

In this case the strut may be composed of articulated or telescopic sections so that its effective length is greater in the extended operative position, with relative movement of the strut sections automatically being related to that of the platform.

The invention will now be further described with reference to the accompanying drawings which illustrate, diagrammatically and by way of example, the various essential and preferred features. In the drawings: Figure 1 is a side view diagrammatically illustrating a device in accordance with the invention as fitted at the stern of a mother vessel; Figure 2 is a similar detail view illustrating an automatically actuated folding extension of a platform of the device; Figure 3 is a detail sectional view illustrating a fulcrum roller assembly associated with the platform; and Figure 4 is a view of the platform, from the inboard end thereof, illustrating the general platform construction and support wheels thereof.

Referring first to the diagrammatic showing of Figure 1 , the device comprises a platform 1 on which a boat 2 is normally stored, the platform being shown in stowed position on a rear deck section 3 at the stern of the mother vessel 4. At its outboard end the platform 1 is connected to the vessel 4 by a fixed fulcrum arrangement at 5. The platform 1 can slide relatively to the fulcrum between the inboard stowed position, shown in full lines, and the outboard operative position shown in chain-dot broken lines in Figure 1, during such sliding movement the platform 1 being able to tilt about the fulcrum axis which is disposed laterally of the fore-and-aft axis of the vessel 4.

Movement of the outboard end of the platform 1, between said stowed inboard and operative outboard positions, is controlled by a strut 6 which in the stowed position, as shown, extends substantially vertically immediately behinri he stern or transom 4a of the vessel. This strut 6 is pivotally supported at its lower end by the transom 4a at 7 and, at its upper end, it is pivotally attached to the outboard end of the platform 1. As can be seen in Figure 1, the upper end of the strut 6 is inwardly cranked at 6a to allow its upper pivotal connection to be substantially coaxial with said fulcrum axis when the platform 1 is in the stowed position, for a reason which will become apparent later in this description.

When in the operative outboard position the platform 1 is supported between the fulcrum arrangement 5 and the upper end of the strut 6, with the platform downwardly inclined to provide a stern ramp for launching and subsequent recovery of the boat 2. The boat will normally be lashed down or otherwise secured to move with the platform 1 until it is in the launching position, when it can be released and floated off. The reverse procedure applies during recovery. The boat 2 is shown in the launching position in chaindot broken lines and as can be seen the rear or outboard end of the platform, when in said operative position, is below the surface of the water.This end of the platform is effectively extended by an optional folding extension 9 which, in the stowed position, provides an upright safety guard rail whereas in the operative launching position of the platform 1 it provides a longitudinal extension thereof.

It will be appreciated that the described movement of the platform 1 out to the operative launching/recovery position, and back again to the inboard stowed position, can be controlled and/or assisted by hand, cable, hydraulic cylinder or other suitable means. The actual manner in which the required hand and/or power assisted movement is achieved will be chosen to fit the particular installation and operational requirements, and can readily be designed by one skilled in the art without further description herein.

As an altemative, or addition, to the folding extension 9 the inboard end of the platform 1 can be provided with a telescopic extension which is an alternative or additional way of extending the effective length of the platform 1. It will be appreciated that the angle of inclination of the platform 1 when in the outboard operative position is largely determined by the length of the strut 6 which in turn is limited by the effective height of the transom 4a. If the latter only allows the use of a short strut which in the arrangement illustrated would provide too steep a ramp angle, the strut 6 may be articulated or telescopic so that its length in the stowed position is less than its effective length when in the operative position, with the relative movement of the articulated/telescopic sections of the strut being related to that of the platform 1.Ways in which the strut 6 could be modified or adapted in this manner will be clear to those skilled in the art without further description herein.

The showing of a telescopically extended platform 1 in Figure 3 illustrates how this can be utilised to stow the platform 1 at a lower level (deck 3) and to utilise it to launch the boat from a higher deck level 10, the platform extension 1 a as shown just compensating for the extra height when the platform is appropriately raised about the fulcrum axis, and allowing the raised platform 1 to be positioned to receive the boat 2 before it is moved outwardly under the control of the strut 6.

This raising movement of the platform is permitted by the described coincidence of the axes of the fulcrum 5 and pivot 8.

Automatic actuation of the folding extension 9 is illustrated in Figure 2 which again shows the stowed position in full lines and, in this case, the position of the platform 1 and extension 9 in broken lines after an initial movement during which the extension 9 automatically operates so that it moves from the upright safety rail position to the operative position in which it provides a longitudinal outboard extension of the platform 1.

The extension 9 is pivotally mounted at 12 between two spaced and parallel steel channels which provide side members 11 of the platform 1, so that the extension pivots about a lateral axis.

Below the pivot 12 the extension 9 has an outwardly curved tail 9a providing in side view a shape similar to that of a hockey stick, and this tail bears against the transom 4a with gravity acting in a direction to move the extension 9 anticlockwise as seen in Figure 2, i.e. towards the operative extended position. As the platform i moves outwardly gravity slowly moves the extension 9 to the operative extended position about the pivot axis 12, pivoting beyond this position being prevented by stop means (not illustrated) on the platform 1. On return of the platform 1 to the stowed position the tail 9a engages the transom 4a with a camming action which automatically results in the extension 9 being returned to the upright safety rail position.

Figure 3 illustrates the fulcrum arrangement 5 at one side of the platform 1, the corresponding outwardly fadng side channel member 11 being shown. This channel member runs on a fulcrum roller 12 which turns freely on a bearing spindle 13 threaded into a fixed mounting bracket 14 and locked in position by a locknut 15. The roller 12 runs on a bearing bush 16 between suitable axial thrust bearings 17. This arrangement allows the desired free sliding and pivoting movement of the platform 1 about the fulcrum axis, i.e. the axis of the spindle 13. Stop means (not shown) limit movement of the channel members 11 on the rollers 12 when the platform reaches the extended operative position.

Figure 4 illustrates a suitable double-skin construction for the fabricated platform 1, the side channel members 11 being spanned by a lower bottom plate 18 and a V-profiled top plate 19, the shallow V of which provides a recess in which the boat 2 sits securely. When in and near the stowed position, i.e. before the total support of the platform is shared by the fulcrum arrangement 5 and the strut 6, some of the weight of the platform 1 has to be supported by the deck 3 in a manner which does not impede the described movement of the platform. For this purpose the side members 11 are provided with plain support wheels 20, one such wheel being mounted adjacent each inboard end comer of the platform 1. These wheels 20 rest, and run, on the deck 3 while the latter is sustaining any share of the platform weight.

Whilst a device in accordance with the invention was primarily conceived for use as a stem launching system, it will be appreciated that such a device can readily be adapted so that a boat can be launched from the side of the mother vessel or from a fixed structure, either at sea or on shore, where the benefit is achieved of the ability to retract the launching ramp when not in use.

Thus the device could be adapted for launching lifeboats and other life-saving equipment, and fors the recovery of objects from the water.

Claims (11)

1. A device for launching and recovering boats from vessels and fixed structures, comprising a platform on which a boat can be stored and which can slide and tilt on a fulcrum arrangement adjacent the edge of a vessel or structure, and an upstanding strut pivoted at its upper end to the platform adjacent the outboard end thereof and pivotally supported at its lower end by the vessel or structure, whereby the strut controls the movement of the outboard end of the platform as the latter is extended to the operative position and supports the platform when in the extended position.

2. A device according to claim 1 and fitted at the stern of a mother vessel, wherein the lower end of the strut is pi\Fota#y pivotaky wpporSd by the transom of the vessel and extends substantially vertically upwards, close to the transom, when the platform is in the stowed position.

3. A device according to either one of the preceding claims, wherein a folding extension is provided at the outboard end of the platform.

4. A device according to claim 3, wherein said folding extension automatically moves to the extended position as the platform is extended, and in the stowed position of the platform is upstanding to form a safety rail at the end of the platform.

5. A device according to any one of the preceding claims, wherein a telescopic extension is provided at the inboard end of the platform.

6. A device according to claim 5, wherein the upper end of the strut is inwardly cranked to provide a pivotal connection with the platform having a pivot axis which substantially coincides with the fulcrum axis when the platform is in the stowed position.

7. A device according to any one of the preceding claims, wherein the strut is extendable so as to be of increased effective length in the extended operative position.

8. A device according to claim 7, wherein the strut comprises relatively articulated or telescopic sections, the relative movement of which is automatically related to that of the platform.

9. A device according to any one of the preceding claims, wherein the platform comprises spaced side members in the form of outwardlyfacing channels, and the fulcrum arrangement comprises aligned freely rotatable rollers mounted on fixed supports and which respectively engage the side channels, and stop means limit movement of the channels on the rollers when the platform reaches the operative extended position.

10. A device according to any one of the preceding claims, wherein the inboard end of the platform has support wheels which support that end when the platform is in the stowed position.

11. A device for launching and recovering boats from vessels and fixed structures, constructed and arranged substantially as herein particularly described with reference to and as illustrated in the accompanying drawings.