WO1994019233A1

WO1994019233A1 - Inflatable deck for a rigid hull lifeboat

Info

Publication number: WO1994019233A1
Application number: PCT/GB1994/000347
Authority: WO
Inventors: Roger Clark
Original assignee: ROGER CLARK (MECHANICAL ENGINEERING) Ltd
Current assignee: ROGER CLARK (MECHANICAL ENGINEERING) Ltd
Priority date: 1993-02-23
Filing date: 1994-02-22
Publication date: 1994-09-01
Anticipated expiration: 1995-08-23
Also published as: AU6111894A; GB9303641D0

Abstract

An inflatable deck is provided on a conventional rigid hull (1) lifeboat to provide an increased deck area from which to recover crew and to which the crew can be more easily embarked. The deck is inflated only during use and comprises a tube (7) secured to the gunwales of the lifeboat.

Description

Inflatable Deck for a Rigid Hull Lifeboat

The present invention is concerned with the provision of an inflatable deck on a lifeboat having a rigid hull and especially but not exclusive, to lifeboats having an enclosed cabin.

Conventionally, an enclosed, rigid hull lifeboat has a hull and a cabin superstructure which encloses a cabin space for passengers. To maximise capacity, the cabin superstructure extends almost to the gunwales of the hull and leaves only just sufficient space for a fit individual to traverse fore and aft of the cabin superstructure by walking on the gunwales. A small fore-deck or aft-deck may be provided.

Because of the minimal deck space it is difficult for passengers to be recovered to the lifeboat from the sea, to disembark to other sea vessels or to be rescued by helicopter. It is an object of the present invention to provide a rigid hull enclosed lifeboat with an emergency deck which can be deployed, at need, to alleviate the aforementioned problems, but which does not occupy excess space when the lifeboat is stored or unduly hinder the manoeuvrability of the lifeboat.

According to the present invention there is provided an inflatable deck for a lifeboat comprising an inflatable tube adapted to be secured to the hull of a rigid hull lifeboat, in a normally deflated condition, and being inflatable so that the inflated tube is supported by abutment with the hull of the lifeboat and provides an extended deck.

Thus, when stored or first launched the lifeboat performs as a conventional rigid hull enclosed lifeboat. However, when it is desired to recover a person from the sea, or when it is necessary to disembark passengers from the lifeboat to another sea vessel or to a helicopter, the tube can be inflated to provide a greatly increased deck area.

When disembarking passengers to another sea vessel the inflated deck not only provides a larger, and consequently safer area from which to disembark, but will also serve as a fender.

When disembarking passengers to a helicopter it is usual for the helicopter to first land a crewman on the lifeboat. In the usual inclement weather the deck of a conventional lifeboat makes a small, fast moving and hard target to land on. The inflatable deck of the present invention can greatly alleviate this problem by providing a larger and softer target.

In recovering personnel from the sea, the inflatable deck provides a large area from which those aboard the vessel can work. The rounded edges of the inflatable deck make it much easier to haul a person out of the sea and the impact of a person with the moving inflatable deck is less likely to cause injury. The tube is secured to the hull or cabin adjacent the gunwales to hang down from the gunwales. From this it will be appreciated that the inflatable deck is not principally supported by virtue of its buoyancy when inflated and thus, in spite of a superficial resemblance, does not perform as the inflatable hull of a conventional rigid hull inflatable vessel. It may here be noted that inflatable and rigid hull inflatable vessels are not sea worthy in extreme weather states such as are frequently encountered around many oil rigs.

It is a significant advantage of the inflatable deck that the deck can be retro-fitted to existing lifeboats.

Preferably the deck is adapted to encircle the lifeboat. It may be desirable to form the deck from several, isolated cells e.g. longitudinally isolated tubes so that each tube forms a cell of the deck and can sustain inflation independently of the others.

Preferably the tube will include flexible internal or external formers arranged to determine the cross- sectional shape of the deck so that the upper deck surface is made relatively flat.

Preferably the tube is secured to the lifeboat by adhesive which bonds the part of the tube wall abutting the lifeboat hull to the hull. It will be appreciated that other means of fixing the inflatable deck to a lifeboat are contemplated and include mechanical fastenings which may be mounted on flaps extending from the tube to engage with cooperating parts of the fastenings cemented to the hull or deck. The mechanical fastenings may include; hook and eye fastenings, laces and overlock fastenings and may be bolted to the deck or hull.

The deflated deck may be cinched by straps or other binding means which will preferably be adapted to release by the effect of the gas introduced to inflate it. The deck will preferably be inflated by air supplied from a compressed air storage cylinder.

The deck may be adapted to mount rails around the periphery of the inflatable deck. Preferably the rails comprise posts held in pockets deployed around the periphery of the deck and a flexible member extending between adjacent posts to be automatically deployed by the inflation of the deck. While it will be appreciated that the advantages of the present invention are amplified by the degree of deck space problem experienced with an enclosed lifeboat, the inflatable deck of the present invention may prove to be of sufficient value in open or only partially enclosed rigid hull lifeboats to be worthwhile. The potential use of the inflatable deck on unenclosed lifeboats or other vessels is to be understood to be within the ambit the present application.

An embodiment of an inflatable deck constructed in accordance with the present invention, will now be described, by way of example only, with reference to the accompanying drawings; in which, figure 1 is a perspective view of a lifeboat equipped with an inflated inflatable deck, figure 2 is an elevation of the bows of the lifeboat with the skirt deflated, figure 3 is an elevation of the bows of the lifeboat with the deck inflated, and figure 4 is a sectional fore and aft elevation of the lifeboat with the deck inflated.

The lifeboat illustrated in the drawings comprises 8a rigid hull 1, a deck 2 and a rigid cabin 3. The lifeboat is of substantially conventional design being suitable for use in emergency disembarkation of crew or passengers from oil rigs, or the like, in hostile weather conditions. The rigid deck 2 of the lifeboat consists of a small foredeck 4, narrow port and starboard decks 5 which extend adjacent the sides of the cabin 3 and an aft-deck 6, which amounts to a continuation of the port and starboard decks 5. The port and starboard decks 5 are of the order of 75mm wide and extend to the gunwales (the upper edges of the sides of the hull 1) .

The inflatable deck comprises an endless tube 7 which is of oval shape to correspond to the shape of the gunwales. An interior wall 8, of the tube is shaped to fit flush against an upper portion of the hull 1 extending downwards from the gunwales. The wall 8 of the tube is adhesively bonded to the hull 1. Thus, when deflated the tube appears as shown in figure 2.

To deploy the inflatable deck for use, air is introduced to the tube 7 from a compressed air supply (not shown) such as a compressed air storage tank. The tube 7 then inflates. While it may prove satisfactory to allow the tube to inflate to an unconstrained cylindrical form, distorted by abutment with the hull 1, the embodiment includes formers (not shown) to constrain the inflated cross-section of the inflatable deck 7 to a roughly triangular section as shown in figure 4. This provides an upper surface 9 which is nearly flat and parallel with the respective adjacent decks 4, 5, 6. The formers may take the form of straps or panels bonded to the inner walls of the tube 7. Alternatively, or additionally, the formers may comprise some sort of rigid or articulated external frame which confines the tube as it expands.

To enhance the usefulness of the inflatable deck, rails 10 are provided around the periphery of the tube 7. The rails can be provided by upright posts 10a received into tubular pockets formed on the outside of the tube 7. The uprights being linked by a flexible rail line 10b.

In the deflated condition the tube 7 can be cinched by straps (not shown) to prevent it being undesirably displaced.

Claims

1. An inflatable deck for a rigid hull lifeboat comprising an inflatable tube (7) adapted to be secured to the hull (1) of a rigid hull lifeboat, in a normally deflated condition, and being inflatable so that the inflated tube (7) is supported by abutment with the hull (1) of the lifeboat and provides an extended deck.

2. An inflatable deck according to claim 1 wherein the tube (7) is secured to the hull (1) or cabin adjacent the gunwales, to hang down from the gunwales.

3. An inflatable deck according to claim 1, or claim 2 which encircles the lifeboat.

4. .An inflatable deck according to any one of claims 1 to 3 wherein formers are arranged to determine the cross section of the deck when inflated, so that the upper deck surface is flattened during use.

5. An inflatable deck according to any one of claims 1 to 4 wherein the tube (7) is secured by adhesive which bonds the part of the lifeboat hull abutting the tube (7) , to the tube (7).

6. An inflatable deck according to any one of the preceding claims wherein the deflated deck is cinched by binding means.

7. An inflatable deck according to claim 6 wherein the binding means are released by the effects of the inflating gas entering the tube (7) .

8. An inflatable deck according to any one of the preceding claims and adapted to be provided with rails (10) which deploy for use around the periphery of the deck.

9. An inflatable deck according to claim 8 wherein the rails comprise posts held in pockets deployed around the periphery of the deck and a flexible member extending between adjacent posts to be automatically deployed by the inflation of the deck.

10 An inflatable lifeboat according to any one of the preceding claims wherein the tube is formed from several longitudinally isolated cells.