TU_FiN is a fin driven sport, leisure and fitness boat. The driver performs an integral low-impact workout on a cross-trainer - a device found in many gyms - which transfers the physical strength into the fin mechanics. With a length of six meters the boat has room for up to two people accompanying the driver. The low stern can be used as a sundeck and allows easy access to and from the water.

TU_FiN is the first boat to be operated by means of a cross-trainer. It transfers the driver's physical strength into two adjoining fins which move in opposite vertical direction (similar to a scuba diver). One step on the cross-trainer results in one flap of the fins. The whole course of movement is specifically coordinated for TU_FiN to remain stable in the water.

Synchronizing the motion sequences of fins and driver allows an ideal transfer of peak performance into forward thrust. This makes it possible for TU_FiN to reach its hull speed of approximately 5.8 knots, provided that the driver is in good physical condition.

Located in the back of the boat between the fins there is the steering rudder.

It is controlled by two levers similar to bicycle brakes which are attached to the handlebars of the cross-trainer, one on each side. A Bowden cable running within the hull connects the levers with the rudder. By pulling the right lever, TU_FiN steers to the right, simultaneously the use of the left lever results in a left turn. The main idea behind this way of steering is not to affect the driver's course of movement and thereby his workout but to make steering intuitive, simple and effective.

The hull of TU_FiN has been optimised for minimum water resistance and maximum stability which is accomplished by the shallow and straight keel line.