Date side Struer
According to computer simulations performed during developing the kayak according to the present invention, it was demonstrated that the kayak implemented in accordance with the presently preferred embodiment of the hull structure having a prismatic ratio of 0.64 and a centre of buoyancy located 51.5 % along the overall length of the hull was 2.9 % faster than the kayak produced by the applicant company.
Although an improvement of 2.9 % may seem fairly low, it has to be realised that the figure has to be compared to a competition situation in which an improvement by 2.9 % of a kayak as compared to a prior art allows the improved kayak to reach the goal after 1000 m, approximately 29 m or equivalent to 4½ lengths of a two-rower kayak before the prior art kayak.
0.62 - 0.68, preferably 0.63 - 0.66, most preferably approximately 0.64, or a prismatic ratio of 0.60 - 0.61; 0.61 - 0.62; 0.62 - 0.63; 0.63 - 0.64; 0.64 - 0.65; 0.65 - 0.66; 0.66 - 0.67; 0.67 - 0.68; 0.68 - 0.69; 0.69 - 0.70, preferably approximately 0.63 - 0.64 or 0.64 - 0.65. The kayak according to claim 1, said deck including a single manhole and defining a specific maximum length of 5.20 m and a maximum width of 42 cm, and said kayak in total having a weight of minimum 12 kg. The kayak according to claim 1, said deck including two manholes and defining a specific maximum length of 6.5 m and a maximum width of 42 cm, and said kayak in total having a weight of minimum 18 kg. The kayak according to claim 1, said deck including four manholes and defining a specific maximum length of 11 m and a maximum width of 42 cm, and said kayak in total having a weight of minimum 30 kg. The kayak according to any of the claims 1 - 4, said maximum frame defining a configuration below water level deviating from a semicircular configuration of the same area as said configuration of said maximum frame, said configuration of said maximum frame defining a central bend defining an angle of 120° - 150°, such as 130° - 140°, e.g.
approximately 140° and defines a maximum height reduced by approximately 10 % as compared to the radius of said semicircle and further defines a maximum width at water level exceeding the diameter of said semicircle by at least 20 %, such as 20 - 25 %, 25 - 30 %, such as approximately 28 %. The kayak according to claim 5, said configuration of said maximum frame defining a level below water level, at which level said configuration of said maximum frame is identical to said semicircle, said level constituting 55 % of said maximum depth of said configuration of said maximum frame below water level. The kayak according to any of the claims 1-6, said kayak including a rudder positioned behind said stern or trailing edge or alternatively and preferably constituting an underlying rudder. The kayak according to any of the claims 1-7, said maximum frame being located at a position behind the centre of said hull and further behind said centre of buoyancy. The kayak according to any of the claims 1 - 8, said hull defining a pointing stern or alternatively a planar stern.
The present invention relates to a kayak or more particularly to a kayak being a competition kayak fulfilling the requirements defined by the International Canoe Federation.
According to these requirements, a kayak may constitute a one-rower kayak, a two-rower kayak or a four-rower kayak.
According to the present invention, a kayak is provided comprising a deck or a top part including a manhole, a hull or bottom part defining a stem or leading edge and a stern or trailing edge, said deck being joint to said hull, said hull defining a specific overall length, a maximum width and a maximum frame, said hull having a centre of buoyancy located behind the centre of said hull, such as at a position at a distance constituting 51 - 53 %, such as 51 - 52 %, preferably approximately 51.5 % of said specific overall length from said stem or leading edge, and said hull defining a prismatic ratio larger than 0.6, such as 0.6 - 0.70, e.g.
As distinct from different kinds of ships or boats, a kayak may not include a keel and therefore, the configuration of the major frame and also the frames of the hull are of the outmost importance as to the stability of the kayak.In the general technical field of ship building, certain technical parameters have been used for at least several decades, namely on the one hand the centre of buoyancy and also the prismatic ratio.The centre of buoyancy defines the centre at which the force generated by the buoyancy of the ship or in the present context, a kayak, is acting as the kayak is submerged in the water by the weight of the rower or the rowers in combination with the weight of the kayak, as the water level defines a perimeter at the outside of the hull of the kayak.The prismatic coefficient is defined as a ratio between the actual volume displaced by the hull below water level and the prism generated by the generator being the major frame of the hull within the maximum length from stem to stern of the ship, or in the present context, the kayak.When considering the prismatic ratio, one would readily think that a low prismatic ratio would provide the fastest kayak and to the knowledge of the applicant company, the prior art competition kayaks have been built with a prismatic coefficient of the order of 0.5 - 0.55, possibly somewhat larger, however, lower than 0.60. a prismatic ratio larger than 0.60 performs better than a hull having a lower prismatic ratio, such as a prismatic ratio lower than 0.55.