Patent ID: 7287481

Claim:
An aerodynamic profile element for energy production using traction force, in particular for driving watercraft, comprising: (a) an upper flexible layer which extends in a transverse direction and a longitudinal direction, (b) a lower flexible layer which extends parallel to the upper layer and which is connected to the upper layer by a plurality of webs extending in the depthwise direction of the profile element, (c) an air-filled internal space between the upper and lower layers, (d) at least one air intake opening for supplying air to the internal space, said opening being arranged between two mutually parallel leading edges of the upper and lower layers, (e) a plurality of pulling lines which are fixed with a first end to spaced locations on the profile element and which are connected with a second end to a pulling cable, (f) a plurality of reefing lines which are fixed at a first end to the layers and/or webs and which are adapted to reduce or increase the size of the profile element by reefing or unreefing the upper and lower layers, and (g) a bar element extending in the longitudinal direction of the profile element to stabilise the aerodynamic profile, wherein the bar element is fixed to the upper and/or lower layer, and/or to a web, and at the bar element at least one of the reefing lines has a first reefing line portion, which extends in the transverse direction of the profile element of the upper or lower layer, respectively, from the fixing point at the first end, and a second reefing line portion, which extends in the longitudinal direction.