WO2008010731A1

WO2008010731A1 - Tube attachment

Info

Publication number: WO2008010731A1
Application number: PCT/NZ2007/000190
Authority: WO
Inventors: Bevan Lawrence
Original assignee: Mapua Limited
Priority date: 2006-07-19
Filing date: 2007-07-19
Publication date: 2008-01-24
Also published as: WO2008010731B1

Abstract

The present invention relates to inflatable boat manufacture. Particularly, although not exclusively, the present invention relates to rigid hull inflatable boats (RIBs) and an inflatable 'boat rope system' for tube attachment. According to one aspect of the present invention there is provided a boat hull for the attachment of inflatable tubes, wherein the hull incorporates a recess that is located around the outside perimeter of the hull and which run the length of the hull characterised in that the recess is configured to receive a secondary inflatable tube connected to a large primary tube such that when the secondary tube is inflated inside the recess of the hull the secondary tube keeps the primary tube attached to the hull. Also described is a method for manufacturing a boat hull for attaching inflatable tubes as described above and shown in Figure 1.

Description

TUBE ATTACHMENT

TECHNICAL FIELD

The present invention relates to inflatable boat manufacture.

Particularly, although not exclusively, the present invention relates to rigid hull inflatable boats (RIBs) and an inflatable 'bolt rope system' for tube attachment.

BACKGROUND ART

Initially, inflatable boats were developed for use in the navy for transporting torpedoes and other cargo as well as other applications. Over time, recreational applications evolved for the smaller boats including pleasure, tender and fishing.

When the stability, flotation and seaworthiness of inflatable boats had become more known, life saving and rescue agencies began using them as tenders on their large vessels.

The stability of an inflatable is a direct result of its large buoyancy tubes and resulting low centre of gravity. Under normal circumstances, it is practically impossible to capsize and the buoyancy of an inflatable, is far greater than that of a traditional boat giving it a higher loading capacity and less susceptibility to swamping.

The buoyancy tubes of an inflatable include several compartments sealed one from the other by internal baffles. Owing to its large air reserve, the boat will stay stable and unsinkable, even with more than one of the independent air chambers deflated.

Inflatable boats are no longer a little dinghy on the back of a large pleasure yacht, but can range up to twelve meters in length and longer. These larger independent boats make perfect water sports, fishing, rescue and military boats particularly because of their flotation, stability and safety.

The benefits of an inflatable boat are seen by their increased performance, handling, coupled with versatility, stability and passenger comfort.

Today "rigid" inflatable boat (RIB) hulls are traditionally manufactured of fibreglass or aluminium and have evolved from their original fabric floors. Now, the only inflatable parts are the tubes or collar around the perimeter gunwales of the deck.

Some RIBs are equipped with an entirely removable tube system that can be disassembled and folded for maintenance, repair, storage and transportation. Once deflated and folded, the space taken up by the inflatable tubes is so compact that transporting and storing becomes extremely easy.

The current method of attaching a removable inflatable tube to a rigid-hull boat utilises a bolt rope (or flange). This is a flap of material containing a section of rope which is used to slide into a slot in the hull to hold a buoyancy tube in place.

A bolt rope is a generic system used in the marine industry. This system originates from sail makers and is common on yacht masts used to attach a sail or canvas. It consists of fabric or sail cloth wrapped around a rope which is pulled into a rebaited track.

This method of attachment has been adapted to inflatable boat manufacture where the tube is equipped with a rope that slides into a slot on the rigid hull.

In the case of aluminium hull inflatable boats, an alloy extrusion exists which can be welded to the aluminium hull to produce the same system.

However, due to the metal oxidation with salt water, the bolt rope often becomes permanently stuck when feeding through the track system causing difficulty to either install or remove the tubes over time. A further disadvantage that occurs with a traditional bolt rope system is that water can leak or siphon into the boat where the tubes are attached to the hull, by circumventing the bolt rope.

Rigid inflatable hull boats manufactured from traditional fibreglass moulding require a more complex mould system to incorporate the built-in slot on each side of the rigid hull. The rope attachment to the tube is then fed into this slot. However, two separate hull sections have to be cured before they are joined. This process is labour intensive and costly.

More recently, boat hulls have also been manufactured out of polyethylene material. This material is lightweight and durable, but it is difficult to attach tubes to this material. The process must again be mechanical as glues will not adhere to the oil based plastic.

It would therefore be useful if there was an alternative method of attaching an inflatable tube to a fibreglass, alloy or polyethylene hull, which can easily be connected or released from the hull.

It is an object of the present invention to provide a tube attachment which addresses the problems highlighted herein with the prior art methods or at the very least provide the public and the trade with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a boat hull for the attachment of inflatable tubes,

wherein the hull incorporates a recess that is located around the outside perimeter of the hull and which run the length of the hull,

characterised in that

the recess is configured to receive a secondary inflatable tube connected to a larger primary tube such that when the secondary tube is inflated inside the recess of the hull the secondary tube keeps the primary tube attached to the hull.

According to another aspect of the present invention there is provided a method for manufacturing a boat hull for attaching inflatable tubes,

characterised by the steps of

a) incorporating a recess that is located around the outside perimeter of the hull running along the length of the hull, to receive a secondary inflatable tube connected to a larger primary tube, and

b) inflating the secondary tube inside the recess of the hull keeping the primary tube attached to the hull, and also in sealing against ingress of water.

Throughout the specification, this method of attaching tubes to hulls will now be simply referred to as an 'inflatable bolt rope system'.

Throughout the present specification the term RIB should be understood to mean a rigid-hull inflatable boat.

In preferred embodiments the tubes or sponsons are inflatable.

In the present application the term "sponson" is defined as the floatation chamber between the gunwales or chines of the RIB.

Throughout the specification the term "gunwale" should be understood to be a nautical term which describes the top edge of the side of a boat.

Throughout the present specification the term "chine" refers to a relatively sharp angle on the outside of the boat hull.

In preferred embodiments the recess is moulded into the hull during manufacture.

In the present application the term "outside perimeter of the hull" should be understood to be any area outside of the hull where a tube can be attached. For example, this may include, but is not limited to the gunwales or chines of a boat hull.

The recess is located around the perimeter of the chines which run the length of the hull and is configured to receive the secondary tube - preferably, semi circular in shape. In one embodiment the recess may be a semi-circular space, depression or cavity within the hull to receive a circular secondary tube.

This should not be seen as a limitation on the present invention however, the recess may be of any other form or profile such as a square or rectangular channel configured to receive the secondary tube.

A smaller secondary tube provides a mechanical attachment to the hull which can easily be connected or released from the hull by inflation or deflation.

Further advantages of this 'inflatable bolt rope system' include when inflated to pressure, this provides a friction attachment to prevent ingress of water where the primary tube is attached to the hull while also securing the tubes to the hull.

In preferred embodiments the tubes or sponsons may be made from a rubber-based fabric such as Hypalon™, Alkrin™, Polymar™, Polyurethane, PVC and mixed derivatives.

In particular, larger RIBs use Hypalon™ or PVC as thicker Hypalon™ fabrics are considered to be one of the stronger and more durable materials in the industry. There are some fabrics that are '2-ply' or a double unit made up of a close-weave mesh of polyester or nylon with Hypalon™. These are used for extreme situations including bumper padding, bow skirts, anti-chafe patches and similar applications.

In one embodiment the Hypalon™ is joined by gluing the material.

Other methods of joining this material may include high frequency welding and thermo bond welding.

In further envisaged embodiments the tubes or sponsons may be made from other fabrics including but not limited to polyurethanes and plastomers such as Strongan™ fabric and other variable alloy mixes. Strongan™ is a high performance third generation plastomer which bonds impervious inner and outer layers to a dense polyester support cloth. It resists cuts and abrasions and is easily repaired in the unlikely event of a puncture.

Apart from its superior toughness and durability, Strongan™ fabric allows the use of a machine-welding process known as "thermobonding", the welding of fabric using hot air. Two sealing strips are thermally bonded to the lapped fabric seams in a continuous electrothermal process. A highly airtight seal is created when the narrow inner strip melts into the collar material. The wider exterior strip functions as a overlapping structural connection and a sealer against water penetration. Thermobonding creates seams that are typically stronger than the fabric itself and produces a better seam than any hand-gluing method.

Preferably, the primary and secondary tubes include a separate end valve each.

In one embodiment the end valves may be semi-recessed. This system provides for quick inflation/deflation, allows easy adjustment of the pressure, is airtight and well protected against sand and other debris.

In preferred embodiments the tubes may incorporate reinforced cone ends.

The reinforced cone ends efficiently protect one of the more heavily attacked zones of the boat.

In preferred embodiments the tubes include internal bulkheads.

These bulkheads totally seal one compartment from the other and equalises the pressure in the tube set.

In the preferred embodiments of the present invention, the RIB will be manufactured from polyethylene material or welded Hypalon^R. Polyethylene hulls are strong, lightweight, durable and manufactured using a roto- moulding process. During the roto-moulding process, two sections of the hull containing the recess can be joined simultaneously.

This reduces the required construction time compared to a traditional fibreglass moulding which requires a more complex mould system. The two separate hull sections have to be cured before they are joined. This process is more labour intensive and costly.

However, it should be appreciated that this is not a limitation on the present invention in any way as other RIB materials are envisaged. Other embodiments envisaged include, but are not limited to fibreglass, aluminium, wood, carbon fibre or kevlar.

In preferred embodiments the hull is a conventional deep V-hull shape at the bow, flattening out to common planing sections aft. This concept incorporates the buoyancy and stability of an inflatable boat with excellent handling characteristics of a deep V-hull ensuring an easy ride in heavy seas.

This should not be seen as a limitation of the present invention however, for a flat hull could conceivably be used for boats which do not need to plane or cover long distances. In other embodiments a progressive V-hull may be used for boats that need to plane quickly, even with heavy loads.

In preferred embodiments the transom is strengthened using multi-layers of material.

This material may include, but is not limited to wood, metal, fibreglass, aluminium or polyethylene layers.

The transoms of inflatable boats must be strong enough to withstand enormous vibrations and stress generated by the weight and power of modern marine engines. It is envisaged that the transom may be configured to accept all types of marine power including outboard, stern drive, inboard or jet propulsion.

In an alternative embodiment of the present invention a half diameter primary tube may be used in preference to a full round primary tube as previously described. For ease of reference throughout the specification, a half diameter tube may be now simply referred to as a "D" tube.

The advantage of a "D" tube is that the inflatable bolt rope serves to not only provide the friction attachment when under pressure, but enables downward tension to be applied on the flat side of the "D" tube pulling the tube taut against the hull while providing its own top attachment method.

Preferably, the "D" tube is utilised for larger vessels which may incorporate polyethylene.

An advantage of a primary and secondary inflatable tube 'bolt rope system' is that it provides a more convenient and simpler method of attaching and detaching inflatable tubes to the hull. To attach or detach the tubes from the hull, simply requires inflating or deflating the secondary tube. This can also assist when transporting boats in containers for shipping.

Also, the inflated pressure of the secondary tube provides a friction element. This prevents water from leaking/siphoning into the boat where the primary tube is attached to the hull. This problem occurs with a traditional bolt rope system.

A further advantage of an inflatable bolt rope over a traditional bolt rope system is that it does not contain a rope that can jam when attempting to attach or detach the tubes from the hull or become oxidized by salt grains which inhibit the extraction of the bolt in alloy hulls. BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 : shows a diagrammatic representation of one preferred embodiment of the present invention; and

Figure 2: shows section A-A viewed from the aft section of one preferred embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

With reference to the figures, there is provided a RIB as indicated by arrow 1.

The RIB (1 ) consists of a hull (2) manufactured from polyethylene material. This material is lightweight, durable and is formed using a roto-moulding process.

Plastic polyethylene powder or grain is placed into a cast or fabricated mould, inside a heated oven, and rotated until the inside is coated. The more powder added, the thicker the product.

The hull (2) requires the moulding to cure over itself therefore not allowing the hull (2) to be physically removed from the mould.

To overcome this problem, a roto-moulding process developed by Cobra Kayaks Limited is employed. This process is design orientated to overcome the associated problems with roto-moulding and incorporates 'Kiss off' (well known terminology used in the roto-moulding industry), inserting and other roto-moulding processes.

A recess (3) is incorporated into the hull (2) located around the perimeter of the chines running the length of the hull. The transom (4) designed for mounting an outboard motor is strengthened using multi-layers of polyethylene material.

A smaller secondary tube (5) with its own separate end valve (6) provides a mechanical attachment to the hull (2) which can easily be connected or released from the hull (2) by inflation or deflation.

When the secondary tube (5) is inflated to pressure, this provides a friction attachment to prevent ingress of water where the primary tube (7) is attached to the hull.

Figure 2 (section A-A) shows an aft section view of the recess (3), hull (2), and primary and secondary tubes (7) and (5).

The primary tubes (7) is fused or bonded to the secondary tube (5) by glue or plastic welding, (8) (as in before described).

The tubes (5) and (7) are of similar length and manufactured out of welded poly alloy fabric as herein described or similar material as previously mentioned. They include separate chambers and are separately inflated.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.

Claims

WHAT WE CLAIM IS:

1. A boat hull for the attachment of inflatable tubes,

wherein the hull incorporates a recess that is located around the outside perimeter of the hull which run the length of the hull,

characterised in that

2. A boat hull for the attachment of inflatable tubes as claimed in claim 1 , wherein the recess is moulded into the hull during manufacture.

3. A boat hull for the attachment of inflatable tubes as claimed in claim 2, wherein the recess is a semi-circular space, depression or cavity within the hull to receive a circular secondary tube.

4. A boat hull for the attachment of inflatable tubes as claimed in any one of claims 1 to 3, wherein the smaller secondary tube provides a mechanical attachment to the hull which connects or releases from the hull by inflation or deflation.

5. A boat hull for the attachment of inflatable tubes as claimed in any one of claims 1 to 4, wherein the hull is manufactured from polyethylene material.

6. A tube for the attachment to the boat hull as claimed in any one of claims 1 to 5, wherein the hull incorporates a recess that is located around the outside perimeter of the hull which run the length of the hull,

characterised in that

the tube includes a secondary inflatable tube connected to a larger primary tube such that when the secondary tube is inflated inside the recess of the hull the secondary tube keeps the primary tube attached to the hull.

7. A tube for the attachment to a boat hull as claimed in any one of claims 1 to 6, wherein the tube is made from a welded poly alloy fabric.

8. A tube for the attachment to a boat hull as claimed in claim 7, wherein the welded poly alloy fabric is joined by gluing.

9. A tube for the attachment to a boat hull as claimed in any one of claims 1 to 8, wherein the primary and secondary tubes include a separate end valve each.

10. A tube for the attachment to a boat hull as claimed in claim 9, wherein the end valves are semi-recessed.

11. A tube for the attachment to a boat hull as claimed in any one of claims 1 to

10, wherein the tubes include reinforced cone ends.

12. A tube for the attachment to a boat hull as claimed in any one of claims 1 to

11 , wherein the tubes include internal bulkheads.

13. A tube for the attachment to a boat hull as claimed in any one of claims 1 to

12, wherein a half diameter primary tube is utilised in place of a full diameter primary tube.

14. A boat which incorporates the hull and tubes as claimed in any one of claims 1 to 13.

15. A method for manufacturing a boat,

characterised by the steps of

a) incorporating into a boat hull a recess that is located around the outside perimeter of the hull running along the length of the hull, to receive a secondary inflatable tube connected to a larger primary tube, and

16. A boat hull for the attachment of inflatable tubes substantially as herein described with reference to and as illustrated by the accompanying drawings.

17. A boat substantially as herein described with reference to and as illustrated by the accompanying drawings.

18. A tube substantially as herein described with reference to and as illustrated by the accompanying drawings.

19. A method for manufacturing a boat for attaching inflatable tubes substantially as herein described with reference to and as illustrated by the accompanying drawings.