Video of how it works

This is the automatic single lever controlled wingsail sailing system. It is a single unit - The main wing controlled by a
smaller wing a "tail" like a windvane. Can be bolted on as a unit to any boat to provide wind thrust.

The system consists of a circular cam which slides and becomes eccentric relative the wingsail pivot axis. The cam transmits movement to the tail which adjusts the wing angle of attack.

The sliding cam is controlled by a single lever, which is in effect the "throttle" lever which controls the thrust of the wingsail

When the cam is in the central position the tail is in line with the wing and therefore provides no thrust. This is the "parking" position where the rig can be left to weathercock with the wind indefinitely.

However, when the cam is moved to an off-centre position by the lever, it controls the tail which in turn adjusts the wing to give thrust, this automatically changes to the other side when the wind comes from the other side of the boat ie. it is self-tacking.

The thrust can be either forward or backward depending on the position of the control lever. In other words the boat can go backwards as easy as forwards by just moving the control lever.

The lever is infinitely adjustable, so power can be increased to maximum or reduced to nothing at will, with every setting in between usable.

Therefore if the wind is too strong, power can be reduced, equivalent to reefing a normal sail.

In use: The single "throttle" control is located in the helm station within the pilot's reach. The pilot moves the "throttle" forward
for greater amounts of thrust from the wingsail or backwards for reverse thrust or braking. (Very useful when coming up to a quay or mooring). Whilst in the middle or neutral position the wingsail is off or "feathered".

There is no other adjustment needed for the operation of the windthrust unit.

Although all this can be done electronically, This system is much simpler and does not need the sensors, servos, chips, power supply, programming. It is simple, robust, easy to repair and understand.