Walker Zephyr Wingsail 43
Larinka is a Walker Zefyr Wingsail 43 trimaran, completed in 2001. The boat was built in England by Wingtek Plc managed by John Walker. The boat was one of four boats of this design that was built prior to the demise of the company. The boat was originally owned by James Wright who carried out many modifications and improvements during his ownership.
The wing is constructed from carbon fibre, fibreglass and cloth and weighs around 600 kg.
The wing is made up of 3 main parts.
When all elements are aligned the whole assembly weather vanes with less wind resistance than a bare mast. To create thrust the tail is rotated causing the wing assembly to pivot away from the wind and "lift" is generated. The flap is adjusted so the effective wing becomes asymmetrical and increases or decreases thrust.
Once the angle to the wind is set, via the tail, the wing will maintain that angle irrespective of where the boat is pointing. As the boat is turned it will eventually reach a point where there is no forward thrust, at this point the tail can be adjusted in the opposite direction which will cause the wing to tack and thrust to be generated in the opposite direction.
The tail can be adjusted to give reverse thrust deliberately, in which case the boat will move backwards.
The adjustments to the wing are made via 2 rotary dials on the dashboard. The adjustments are instantaneous and the thrust created is felt instantly. If forward thrust is applied the boat will accelerate forward. If reverse thrust is then applied the boat will come to a quick stop and then start going backward.
The boom is counterbalanced so maintains angle in spite of boat pitching. In squally conditions, because the wing angle is not fixed to the boat, the wing will rotate as wind angle changes and so the boat is not subject to buffeting like a traditional sailboat.