GB2349850A

GB2349850A - watercraft

Info

Publication number: GB2349850A
Application number: GB0010994A
Authority: GB
Inventors: Jack Barclay
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-08
Filing date: 2000-05-08
Publication date: 2000-11-15
Anticipated expiration: 2020-05-08
Also published as: GB9910598D0; GB2349850B; GB0010994D0

Abstract

A watercraft with a rigid or semi-rigid hull 20 and a collar 1 formed from a mouldable plastics material. The collar can be formed separately and attached to the hull in one or a few pieces saving on weight and allowing the construction of a craft having superior handling characteristics than those with conventional inflatable collars.

Description

2349850 1 "Watercraft" 2 3 -is invention relates to a watercraft. Rigid 4

inflatable boats are well known and generally comprise a fibreglass hull with an inflatable collar 6 surrounding it. The collar can generally be formed 7 of rubberised canvas material such as hypalon (M 8 which is attached around the periphery of the hull, 9 and inflated. The collar can be prone to punctures, and although repairs are possible, these are 11 difficult and expensive. The collars also become 12 porous with age.

13 14 It is also known to construct boats made entirely of is plastic. The flat surfaces of the hulls on such 16 vessels are prone to cold moulding which has adverse 17 affects on the appearance and performance of the 18 boat. In addition, the collars on such boats are 19 formed from straight pre-fabricated sections which are welded at angles to one another. This is 2 1 difficult to do and the welds constitute weak spots in the collar which may be prone to failure.

4 According to the invention there is provided a 5 watercraft comprising a rigid or semi-rigid hull and 6 a collar, wherein the collar comprises a mouldable 7 plastic. 8 9 The collar is preferably semi-rigid. The collar can 10 be formed of high density polyethylene (HDPE), or a 11 similar mouldable plastic. The hull can be any rigid 12 material such as aluminium or fibreglass. 13 14 The collar and the hull can comprise separate pieces 15 which can be attached during construction of the 16 watercraft. In a preferred method, the collar is 17 formed to the same shape as the periphery of the hull 18 to which it will be attached, e.g. by heating the 19 collar and allowing it to set to the desired shape. 20 This can be achieved by heating an HDP or HDPE member 21 with a conventional hot air blower, covering the 22 member with a thermally insulating blanket, and 23 fixing the member in a jig of the desired shape and 24 allowing it to cool. Once the member has cooled and 25 has been removed from the jig it will retain its 26 desired shape. The jig itself can be heated in order 27 to form the member. The steps of heating and fixing 28 the member to the jig can be carried out in any 29 desired order. 30 3 1 Formers are preferably used to control the bending of 2 the member.

3 4 The hull is preferably formed separately e.g. by conventional methods for working aluminium or 6 fibreglass, and can be attached to the formed collar 7 by bolting to a flange which can be welded to the 8 collar to extend therefrom.

9 It is preferred that the collar is formed from a 11 small number of pieces and in a preferred embodiment, 12 the collar is formed from a single piece which has 13 been formed to the desired shape. It is acceptable, 14 however, for the collar to be formed from two initially separate members which are formed to adopt 16 the shape of opposite sides of the hull, and are 17 joined together, for example at the bow. It is 18 preferred that any joints between separate pieces of 19 the collar are made in a straight line.

Alternatively, the two pieces of the hull can be 21 joined to a connector, for example at the bow, 22 without the necessity for welding the two pieces 23 together.

24 An embodiment of the invention will now be described 26 by way of example and with reference to the 27 accompanying drawings in which:

28 29 Fig. 1 is a schematic diagram showing a process for forming a collar of a watercraft; 4 1 Fig. 2 is a cross-sectional view showing the 2 means of attachment of the collar to the hull; 3 Fig. 3 is a side view of the watercraft; 4 Fig. 4 is a view of the Fig. 3 watercraft from beneath; 6 Fig. 5 is a front view of the watercraft; 7 Fig. 6 is a sectional view through the hull of 8 the watercraft; 9 Fig. 7 is a side view of the watercraft; Fig. 8 is a plan view of the watercraft; 11 Fig. 9 is a rear view of the watercraft; 12 Fig. 10 is a plan view of a former; and 13 Figs. 11 & 12 are side views of a member in a 14 former assembly.

is 16 Referring now to the drawings, Fig. 1 shows a member 17 forming a portion of a collar 1 of HDPE which is 18 covered with a thermally insulating blanket 2 and is 19 being heated by heat source 5. As the member heats up and becomes pliable, it is fitted onto a former 10 21 which is curved in a shape which matches the hull of 22 the watercraft. The member is heated to 1800 to 23 2000C and is kept at that heat for several minutes 24 while being held onto the former 10 in the desired shape. After the member has cooled on the former, it 26 retains the shape and can be fitted to the hull.

27 Conventional formers known in the art can be used and 28 can be adjustable in shape if required, although a 29 dedicated former fabricated to the desired shape of the hull will produce the best results. In the 31 example shown, the former mimics the shape of one S 1 side of the hull, although it is possible to use a 2 former which mimics the shape of substantially the 3 whole circumference of the hull which the collar is 4 desired to cover, so that the collar 1 can be formed 5 in a single piece. The collar does not generally 6 cover the transom at the stern of the boat. 7 8 once the collar 1 is in the desired shape, a plastic 9 flange if is welded or glued to the inside of the 10 curve and the flange if is then glued and/or bolted 11 to the hull 20. Alternatively, the flange if can be 12 bolted and/or glued to the hull 20 and thereafter can 13 be welded to the collar 1. 14 15 A multi-hulled design of craft such as a catamaran is 16 possible using a collar of, for example, HDPE, and 17 twin hulls of, for example, aluminium. Since the 18 moulded plastic collar is semi-rigid, it is more 19 resistant to abrasion and abuse than conventional 20 designs of inflatable collars, and also allows 21 fittings or equipment to be mounted thereon more 22 easily. Semi-rigid collars of this type are also 23 more stable than inflatable collars, and are easier 24 to join to the hull, since they can be moulded to the 25 precise shape whereas inflatable collars generally 26 assume the shape of least resistance, which may not 27 match the shape of the hull, and may lead to areas of 28 the join being slack and therefore prone to vibration 29 at high speeds. The use of separate materials for 30 the collar and hull allows the construction of a 31 lighter boat than would be possible with all plastic 6 1 designs of RIB, by easier and less expensive 2 techniques. 3 4 Figs. 10, 11 and 12 show details of a former assembly 5 for use in bending a member in the invention. The 6 former assembly comprises an arrangement of generally 7 circular formers in the form of hoops or solid discs 8 shown in plan view in Fig. 10 and in side view in 9 Figs. 11 and 12. The formers 100 have eyes or 10 apertures 102, 103, 104 and 105 spaced at equal 11 distances around their circumferences for receiving 12 guide wires 110. The formers are placed end to end 13 so that the respective guide wire apertures 102, 103, 14 104 and 105 are aligned in each of the formers 100, 15 and placing a spacer 115 between each pair of guide 16 wire apertures 102 and 104. The spacers 115 can be 17 of any desired thickness, and can vary in shape, 18 length or thickness in order to induce different 19 bending characteristics as will be described later. 20 21 Wires 110 are then threaded through wire apertures 22 102, 103, 104 and 105 and, where present, through the 23 spacers 115 between the respective pairs of guide 24 wire apertures 102 and 104 between the formers 100. 25 No spacers are introduced on the guide wires passing 26 through apertures 103 and 105 at the top and bottom 27 of the former guide. 28 29 once assembled, the former guide is inserted into the 30 bore of the member 120 to be bent, and is manoeuvred 31 into the correct area so that the spacers 115 with 7 1 the desired bend characteristics are located in the 2 portion of the member to be bent accordingly. Once 3 suitably positioned, the upper wire passing through 4 the apertures 103 is tensioned at approximately 1.5 5 to 2 tonnes of tension per 5 metre length of member. 6 This tension pivots the formers 100 around the 7 spacers 110 to an extent determined by the shape and 8 thickness of the spacers 110. The member 120 adopts 9 the same configuration as the tensioned guide former 10 and is heated up to around 1000 1-20C for the 11 period required for bending. This varies from around 12 1 hour to 6 hours typically with member comprising 13 HDP monopolymer, but the temperature and tension can 14 be varied in accordance with the thermoplastic 15 characteristics of other materials being used. once 16 the member 120 has attained the desired shape, it is 17 held in that position by means of the tension applied 18 to the wire passing through the guides 103, and left 19 until it has set in that shape. 20 21 The member 120 expands during the heating process and 22 contracts to some extent around the guide former 23 which remains in position in the finished bent 24 member. 25 26 Solid members can also be bent using this technique 27 using formers 100 comprising hoops through which the 28 solid member passes and having eyes for tensioning 29 guide wires on their outer surfaces. Such a former 30 can be removed from the bent member once it has 31 attained the desired shape and cooled down, but it is 8 1 advantageous to leave the former in position in the 2 bore of a hollow member, since this maintains the 3 structural integrity to some extent. 4 5 It is often a useful feature to coat the formers 100 6 with plastic or rubber material to prevent them 7 acting as heat sinks. The wires passing through the 8 middle apertures 102 and 104 can typically be used to 9 suspend the member in an oven. Typically all wires 10 are of steel or some other heat resistant material. 11 12 Therefore, the present invention also provides a 13 method of bending a member comprising supporting the 14 member with at least two formers and pivoting the is formers relative to one another in order to introduce 16 a bend in the member. 17 18 Modifications and improvements can be incorporated 19 without departing from the scope of the invention. 20 9

Claims

1 Claims

2 1 A watercraft comprising a rigid or semi-rigid 3 hull and a collar, wherein the collar comprises a 4 mouldable plastic.

6 2 A watercraft as claimed in claim 1, wherein the 7 collar is rigid or semi-rigid.

8 9 3 A watercraft as claimed in claim 1 or claim 2, wherein the collar comprises polyethylene.

11 12 4 A watercraft as claimed in any preceding claim, 13 wherein the hull comprises a rigid material.

14 5 A watercraft as claimed in any preceding claim, 1G wherein the collar and the hull comprise separate 17 pieces that are attached during construction of the 18 watercraft.

19 6 A watercraft as claimed in any preceding claim, 21 wherein at least a portion of the collar is formed to 22 the same shape as the periphery of the hull to which 23 it will be attached.

24 7 A watercraft as claimed in claim 6, wherein the 26 collar is formed by heating and being allowed to set 27 in a desired shape.

28 29 1 8 A watercraft as claimed in claim 6 or claim 7, 2 wherein formers are used to control the bending of 3 the member.

4 9 A watercraft as claimed in any preceding claim, 6 wherein the hull is attached to the formed collar by 7 bolting to a flange extending from the collar.

8 9 10 A watercraft as claimed in any preceding claim, wherein the collar is formed from at least two 11 pieces.

12 13 11 A watercraft as claimed in any preceding claim 14 wherein the collar is formed from two initially is separate members which are formed to adopt the shape 16 of opposite sides of the hull, and are joined 17 together at the bow.

18 19 12 A watercraft as claimed in claim 11, wherein the two pieces of the hull are joined to a connector at 21 the bow.

22 23 13 A method of making a watercraft, the method 24 comprising providing a rigid or semi-rigid hull, forming a plastic collar around at least a portion of 26 the hull to conform to the shape of the portion of 27 the hull and attaching the collar to the hull.

28 29 14 A method as claimed in claim 13, wherein the collar is formed in at least two separate pieces that 31 are subsequently attached together.

11 A method as claimed in claim 13 or 14, wherein 3 at least a portion of the collar is heated and cooled 4 in a jig and/or a former to hold it in a desired shape, and wherein the shape is maintained by the 6 collar after cooling.

7 8 16 A method as claimed in claim 15, wherein the jig 9 and/or the former is heated.

11 17 A method as claimed in claim 15 or 16, wherein 12 the collar is at least-partially covered with an 13 insulator and allowed to cool while being held in the 14 desired shape by the former and/or jig. 15 16 17