GB2168932A

GB2168932A - Inflatable boats

Info

Publication number: GB2168932A
Application number: GB08432703A
Authority: GB
Inventors: Peter C Gordon
Original assignee: Lifeguard Equipment Ltd
Current assignee: Lifeguard Equipment Ltd
Priority date: 1984-12-28
Filing date: 1984-12-28
Publication date: 1986-07-02
Also published as: GB2168932B; GB8432703D0

Abstract

The hull space (16) between the deck (15) and the lower skin (14) of an inflatable boat is in free communication with the exterior of the hull (11) but contains buoyancy bags (17) which, when inflated, lift the boat sufficiently out of the water to assist further lifting due to the boat's motion over the water, thereby enabling the boat to pick up speed more rapidly. When the boat is stationary, the buoyancy bags can be deflated to improve stability, thereby enabling divers to work from the boat more easily. <IMAGE>

Description

SPECIFICATION Improvements in inflatable boats The present invention relates to inflatable boats and more particularly to an inflatable boat of the kind having a rigid hull around whose periphery are attached inflatable buoyancy tubes. Such a boat is often called a "rigid hull inflatable".

The rigid hull of a rigid hull inflatable usually comprises a hull skin and a deck overlying the hull skin, so that a space is formed between the skin and the deck.

In one kind of rigid hull inflatable, the space between the hull skin and the deck is either totally sealed or is filled with buoyant material. Alternatively, the hull space may be made air tight. In either event this space provides additional buoyancy at all times. A disadvantage of this arrangement is that the boat is inclined to be unstable when it is stationary. This makes it difficult for divers working from the boat leaving the boat and climbing back on board.

In another kind of rigid hull inflatable, the space between the hull skin and the deck is freely connected to the water in which the boat is floating.

This is sometimes called a flooding facility. The advantage of this facility is that the boat settles low in the water when it is stationary, the necessary buoyancy being provided only by the buoyancy tubes. This renders the boat very much more stable when it is stationary, thereby enabling divers to work from the boat much more easily. When the boat is moving, the movement itself lifts the boat in the water and the water within the hull space gradually drains away thereby enabling the boat to lift higher in the water until it reaches its full speed.Of course, the drag is very much greater whilst the boat is still low in the water and a disadvantage of the provision of the prior art flooding facility is that, particularly in the case when the boat is fitted with a small engine, the boat is very slow to pick up speed and in an extreme case the engine may not be able to develop enough power to lift the boat out of the water sufficiently to commence the draining operation.

According to the present invention, an inflatable boat comprises a rigid hull, inflatable buoyancy tubes secured to the periphery of the hull, the hull comprising an outer or lower skin and an upper deck defining a hull space therebetween, and at least one inflatable buoyancy bag disposed in said hull space, the latter being in free communication with the exterior of the hull.

An advantage of an inflatable boat according to the invention is that the additional buoyancy bags in the hull space can be deflated when the boat is stationary and diving operations are taking place and can be reinflated to lift the boat in the water before the boat moves off.

It is not necessary for the hull space to be completely filled with buoyancy bags when inflated since only a small additional buoyancy may be needed to assist the lifting of the boat as it moves off, further lift being achieved by the movement of the boat in the water.

The invention is further described by way of Example with reference to the accompanying drawings, in which; Figure 1 is a plan view of an inflatable boat according to the invention; Figure 2 is a side elevation of the boat; and Figure 3 is a transverse cross-section of the boat.

The inflatable boat or "rigid hull inflatable" shown in the drawings comprises buoyancy tubes 10 attached to the periphery of a rigid hull 11. A stern transom 12 is secured to the rigid hull 11 and/or to the rear ends of the buoyancy tubes 10 and serves for the mounting of one or more outboard motors (not shown).

As shown in Figure 3, the rigid hull 11 comprises a lower or outer skin 14 and a deck 15. The space 16 defined between the skin 14 and deck 15 is open at the rear so that water can flow freely into and out of this hull space. Buoyancy bags 17 are located in the hull space 16 and can be easily deflated and reinflated. When the buoyancy bags 17 are deflated and the boat is stationary, it settles low in the water in the same way as with a boat provided with the known flooding facility. This renders the boat very stable, thereby facilitating the manoeuvres of diving personnel leaving and entering the boat. When it is desired to move off, the buoyancy bags are inflated either by means of a pump or from a bottle of compressed air or other gas. The buoyancy is thereby increased, lifting the boat in the water, thereby reducing its drag when the outboard motor or motors are started.The boat is thereby able to accelerate more rapidly when it moves off and the movement of the boat lifts it further out of the water so that water remaining in hull space 16 will drain away and the boat can reach its maximum speed very quickly even when provided with a low power outboard motor.

The buoyancy bags 17 need not be sufficiently large or sufficiently great in number to fill the hull space 16 when the buoyancy bags are inflated but they must be located so as not to influence adversely the position of the centre of buoyancy when the bags are inflated.

Typically, the buoyancy bags will be arranged in two rows longitudinally of the boat and each row can contain, for example, three bags. The deck 15 is provided with openings through which protrude filler valves 18 connected to the buoyancy bags.

1. An inflatable boat comprising a rigid hull, inflatable buoyancy tubes secured to the periphery of the hull, the hull comprising an outer or lower skin and an upper deck defining a hull space therebetween, and at least one inflatable buoyancy bag disposed in said hull space, the latter being in free communication with the exterior of the hull.

2. A boat as claimed in claim 1, in which only a part of the hull space is filled with buoyancy bags, when inflated.

3. A boat as claimed in claim 1 or 2, in which

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in inflatable boats The present invention relates to inflatable boats and more particularly to an inflatable boat of the kind having a rigid hull around whose periphery are attached inflatable buoyancy tubes. Such a boat is often called a "rigid hull inflatable". The rigid hull of a rigid hull inflatable usually comprises a hull skin and a deck overlying the hull skin, so that a space is formed between the skin and the deck. In one kind of rigid hull inflatable, the space between the hull skin and the deck is either totally sealed or is filled with buoyant material. Alternatively, the hull space may be made air tight. In either event this space provides additional buoyancy at all times. A disadvantage of this arrangement is that the boat is inclined to be unstable when it is stationary. This makes it difficult for divers working from the boat leaving the boat and climbing back on board. In another kind of rigid hull inflatable, the space between the hull skin and the deck is freely connected to the water in which the boat is floating. This is sometimes called a flooding facility. The advantage of this facility is that the boat settles low in the water when it is stationary, the necessary buoyancy being provided only by the buoyancy tubes. This renders the boat very much more stable when it is stationary, thereby enabling divers to work from the boat much more easily. When the boat is moving, the movement itself lifts the boat in the water and the water within the hull space gradually drains away thereby enabling the boat to lift higher in the water until it reaches its full speed.Of course, the drag is very much greater whilst the boat is still low in the water and a disadvantage of the provision of the prior art flooding facility is that, particularly in the case when the boat is fitted with a small engine, the boat is very slow to pick up speed and in an extreme case the engine may not be able to develop enough power to lift the boat out of the water sufficiently to commence the draining operation. According to the present invention, an inflatable boat comprises a rigid hull, inflatable buoyancy tubes secured to the periphery of the hull, the hull comprising an outer or lower skin and an upper deck defining a hull space therebetween, and at least one inflatable buoyancy bag disposed in said hull space, the latter being in free communication with the exterior of the hull. An advantage of an inflatable boat according to the invention is that the additional buoyancy bags in the hull space can be deflated when the boat is stationary and diving operations are taking place and can be reinflated to lift the boat in the water before the boat moves off. It is not necessary for the hull space to be completely filled with buoyancy bags when inflated since only a small additional buoyancy may be needed to assist the lifting of the boat as it moves off, further lift being achieved by the movement of the boat in the water. The invention is further described by way of Example with reference to the accompanying drawings, in which; Figure 1 is a plan view of an inflatable boat according to the invention; Figure 2 is a side elevation of the boat; and Figure 3 is a transverse cross-section of the boat. The inflatable boat or "rigid hull inflatable" shown in the drawings comprises buoyancy tubes 10 attached to the periphery of a rigid hull 11. A stern transom 12 is secured to the rigid hull 11 and/or to the rear ends of the buoyancy tubes 10 and serves for the mounting of one or more outboard motors (not shown). As shown in Figure 3, the rigid hull 11 comprises a lower or outer skin 14 and a deck 15. The space 16 defined between the skin 14 and deck 15 is open at the rear so that water can flow freely into and out of this hull space. Buoyancy bags 17 are located in the hull space 16 and can be easily deflated and reinflated. When the buoyancy bags 17 are deflated and the boat is stationary, it settles low in the water in the same way as with a boat provided with the known flooding facility. This renders the boat very stable, thereby facilitating the manoeuvres of diving personnel leaving and entering the boat. When it is desired to move off, the buoyancy bags are inflated either by means of a pump or from a bottle of compressed air or other gas. The buoyancy is thereby increased, lifting the boat in the water, thereby reducing its drag when the outboard motor or motors are started.The boat is thereby able to accelerate more rapidly when it moves off and the movement of the boat lifts it further out of the water so that water remaining in hull space 16 will drain away and the boat can reach its maximum speed very quickly even when provided with a low power outboard motor. The buoyancy bags 17 need not be sufficiently large or sufficiently great in number to fill the hull space 16 when the buoyancy bags are inflated but they must be located so as not to influence adversely the position of the centre of buoyancy when the bags are inflated. Typically, the buoyancy bags will be arranged in two rows longitudinally of the boat and each row can contain, for example, three bags. The deck 15 is provided with openings through which protrude filler valves 18 connected to the buoyancy bags. CLAIMS

3. A boat as claimed in claim 1 or 2, in which buoyancy bags are arranged in the hull space in two rows longitudinally of the boat.

4. A boat as claimed in claim 1, 2 or 3, in which the deck is provided with openings through which filler valves connected to the buoyancy bags protrude.

5. An inflatable boat, constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.