SEAir, a French startup focused on foil technology, has modified David Raison’s famous mini- Magnum 747, and converted it to a foiling design capable of full continuous flight out of the water. On January 25, 2017, the boat achieved stable and balanced flight on its second outing; flying above the waves, at a speed of 15 knots in a wind of 8 knots.
The boat breaks new ground in foiling on an offshore mono-hull. Unlike Arkema 3, and the foiling Vendée Globe IMOCA 60’s which fly above the water for several seconds at a time with the help of their foils, then crash back into the water, the SEAir Mini 747 flies fully above the water. The boat is designed to lift out of the water at around 8 to 10 knots of true wind.
In addition to the foils on each side, the boat has a centreboard to provide lateral resistance, a canting keel that has remained unchanged from the boats previous non-foiling incarnation, and two rudders. The team is working on a system to lift the upwind rudder out of the water once the boat has achieved flight, as initial testing has shown that the second rudder is increasing drag whilst providing little in terms of extra lift or control once the boat is airborn. The keel has not been made lighter as it’s righting moment is needed and because it is needed for upwind performance. The fact it is relatively heavy also gives the boat extra stability in flight
As on the GC32s, the control of the foils is done manually, using an endless screw mechanism. This allows adjustment of their angle of incidence whilst sailing. The twin rudders are equipped with the same system.
As this boat is intended to be used offshore, it faces some additional challenges to achieve stable flight. In a seaway - the foil has to be at the correct angle relative to the waves. In order to achieve this , the SEAir team has developed a patent pending multi-axial foil control system that allows adjustment of the foil’s rake,cant and toe (the angle of the foil relative to it’s central axis).
For the moment the boat is asymetric and can only fly on port tack – as the team wanted to validate the foil design and it’s position,
During the first half of 2017, the boat will undergo further sea trials to test various offshore take off and stabilisation settings. After which will come some record breaking attempts to demonstrate that the foils and their systems are durable and can withstand tough sea conditions. In its current configuration the boat is not quite class legal to participate in the Mini-transat and other Mini races and would need slight modifications which would result in a decreased sail area…