BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

THIS INVENTION relates to a watercraft seat. The invention is particularly suitable for, but not limited to, a kayak seat. The term "kayak" shall be used to include other watercraft such as canoes, rowing shells, sculls and the like.

2. PRIOR ART In a kayak, the seat is fixed, and this places some limit on a rower's body twist. Even amongst the top competitors, full power in the stroke is only available for part of the stroke. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pivotal seat which enables the rower to generate full (or increased) power through the full stroke of the paddles.

It is a preferred object to provide a seat where the effective body twist is increased, together with an increase in the length of the stroke.

It is a further preferred object to provide a seat where the kayak remains more stable with less wobbling or 'porpoising', as it travels through the water.

Other preferred objects will become apparent from the following description.

In a broad aspect, the present invention resides in a seat for kayaks or the like including: a base mountable in a shell or hull of a kayak; a seat portion to support the rower; and pivot means interconnecting the base and the seat portion to allow relative rotation therebetween.

The base is preferably moulded or formed (eg. in timber, carbonfibre, or fibre - or glass-

reinforced plastics resin) to conform to the shape of the shell, and may have one or more mounting holes to allow adjustable mounting therein.

The seat portion is also preferably moulded of a formed tubular, carbonfibre or reinforced plastics or resin, and preferably has a shape moulded to conform to the rower's rump.

Integral, upwardly-directed "lumbar" extension may be provided on the rear of the seat portion.

Preferably, the pivot means has a vertical pivot axis substantially aligned with or near to, the rower's anus when the seat is in use.

Preferably, friction reducing washers or discs are provided between the base and seat portion to allow free pivotal rotation therebetween, and one or more height adjustment spacers may be provided between the base and the seat portion.

In an alternative embodiment, a bearing assembly (eg. a ball bearing) may be interposed between the base and seat portion to provide substantially frictionless rotation therebetween. In a further alternative embodiment, one or more sliding tracks may interconnect the base and seat portion. Preferably, the pivot axis is adjustable relative to the seat portion to suit the rower's individual reguirements.

An extension may extend forwardly of the seat portion and be provided with a substantially vertical removable and/or adjustable guide. The guide is engaged by the rower's (preferably upper) thighs to assist in rotating the seat portion relative to the base as the rower twists through each stroke. The base may be formed by, or lies integral with, the shell or hull of the kayak. Where the base

is removable, it may be secured to the shell by suitable fasteners (eg. screws, studs), releasable clips and/or releasable attachment strips (eg. "VELCRO" (Registered Trade Mark) strips). BRIEF DESCRIPTION OF THE DRAWINGS

To enable the invention to be understood, a number of preferred embodiments will now be described with reference to the accompanying drawings, in which: FIG. 1 is a plan view of a first embodiment the seat, in the straight ahead position, in the cockpit of a kayak;

FIG. 2 is a similar view with the seat shown in the range of its pivotal movement; FIG. 3 is a part sectional side view of the seat;

FIG. 4 is a schematic sectional side view of a portion of the seat and base of a second embodiment; FIG. 5 is a similar view of a third embodiment;

FIG. 6 is a schematic plan view of a curve track assembly for a fourth embodiment;

FIG. 7 is a schematic sectional view taken showing the track at line 7-7 on FIG. 6;

FIG. 8 is a similar view of a fifth embodiment; and

FIG. 9 is a view taken on line 9-9 on FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 to 3, the seat 10 is designed to be fitted to the cockpit 11 of a kayak 12.

The seat 10 has a base 20, moulded of eg, carbonfibre or fibreglass, which is shaped to conform to the bottom of the cockpit 11 and which has holes

(not shown) to enable it to be adjustably mounted in

the cockpit 11. The base 20 has a central planar portion 21.

The base 20 may be releasably secured to the bottom of the cockpit 11 by "VELCRO" (Registered Trade Mark) strips 22 - these strips 22 can allow the rower 101 to adjust the position of the seat 10 in the cockpit 11 to suit his/her personal requirements (eg. to accommodate different leg lengths).

The seat portion 30 is moulded in one or two sections from fibreglass or different materials. The lower portion 31 has a planar bottom wall 32 surrounded by a substantially circular side wall 33, the latter supporting the profiled upper seat portion 34. This upper seat portion 34 has recesses 35 for the rower's cheeks, and an inclined back wall 36 and can be moulded to suit each rower. A pivot pin 40, with a retaining nut 41, pivotally interconnects the seat portion 30 to the base 20 so that the seat portion 30 can pivot between the positions shown in the dashed and dotted outlines in FIG. 2 about an axis A.

Experiments have shown that the position of the pivot pin 40 is critical for maximum performance and it is preferably aligned with, or closely adjacent to the rower's anus 100 when the seat is in use. However, by making the pivot point, and thereby axis A, adjustable in the seat position 30, a rower 101 can tailor the seat to his/her personal requirements. By placing friction - reduction washers, discs or plates 42, 43 (eg of 'TEFLON' (Registered Trade Mark)) between the central planar portion 21 of the base 20 and the planar bottom wall 32 of the lower seat portion 31, the seat portion 30 will freely pivot relative to the base 20. One or more spacers may be provided to enable the seat height to be adjusted as required by each rower.

While the pivoting seat may only provide 25-50mm effective twist of the rower's body, the following benefits are noted:

(a) the rowing stroke may be increased by 100-200mm;

(b) full (or greater) power is possible through the full length of the stroke;

(c) the paddles come out of the water more easily and cleanly; (d) the kayak is more stable as the rower's back side does not tend to force itself up the back wall of the seat;

(e) padding is easier; and

(f) less drive is required off the feet to generate the same power. As the length of the stroke is increased, less strokes are received to travel a given distance.

In tests, it has been found that rowers with strong leg actions tend to have their rumps ride up the rear of the seat portion 30. To counter this, a covering material (eg chamois) may be applied to the seat to increase the friction between the seat portion 30 and the rower's shorts. Alternatively, the seat portion 30 may be formed with, or provided with, a roughened surface.

An adjustable guide 50, engageable by the rower's thighs 102, may be provided in an extension

51 at the front of the seat portion 30 (see FIG.3).

As the rower twists, one thigh 102 engages the guide 50 to cause the seat portion 30 to rotate relative to the base 20. The guide 50 may be omitted if not required.

The seat portion 30 and the base 20 may be manufactured from fibreglass, glass-reinforced plastic, carbon fibre, metal, timber (eg. laminated veneer) or other suitable materials and/or a combination of these.

Referring now to FIG. 4, the pivot pin 40 and friction reducing washers 42, 43 may be replaced by a ball bearing assembly interposed between the base 220 and the seat portion 230. As indicated by the dashed lines, a pivot pin 240 may be retained to secure the base 220 and seat portion 230 together, and to define the axis of rotation A of the seat portion 230.

In the third embodiment of FIG. 5, the seat portion 330 has a plurality of rollers 360, supported by brackets 361, which run in tracks 362, at least part-circular in plan view, on or in the base 320.

As shown, the tracks 362 may be moulded into the base 320 to allow a low seat height relative to the base. Alternatively, the base 320 may be planar (dashed lines) and the tracks 362 formed by ribs 363.

FIG. 6 shows two curved tracks 462, in plan view, about a pivot pin 440. Each track 462 receives at least one slidable block 460, connected to the seat 430 by a bracket or post 461. The blocks 460 and tracks 462 are formed of materials, eg "Teflon" and stainless steel which have a low coefficient of friction. In the final embodiment of FIGS. 8 and 9, wheeled trolleys 560, attached to the seat portion 530 by posts 561, travel in curved tracks 562 similar to the curved track 462 in FIGS. 6 and 7.

As shown in FIG. 9, each trolley 560 may have two or four wheels 569.

Various changes and modifications may be made to the embodiments described without departing from the present invention.