Wouter,

I am still not in position to give a definitive evaluation of the Catri concept, for mine is still being laminated now. However, I can pass the information received from people sailing the boat in Sweden and in the US, under the light of pieces of information received from the designer.

As you correctly stated, the concept is to lift only 90% of the displacement with the foils, but the boat does not always sail this way.

The new owner of the first Catri 26 prototype, from Sweden, told me that he likes to sail singlehanded with one or two rreefs in heavy winds. Under this conditions, he says that the boat sails totally airborne (supported by foils only) and is the only boat around that can rival the windsurfers.

The trick is that the boat is designed for a bigger crew and the displacement is lower when singlehanding. This enables the boat to be 100% supported by the foils.

He also said that, contrary to your expectations, the self-stabilizing system (rear outrigger foils) continues to work under this conditions and the boat remains remarkably stable and easy to sail.

The reasons appear to be:

1) there is far more lift in the forward bruce foil then in the rear foils - just look at their sizes.

2) the position of the bruce foils in front of the mast give better leverage. (with the added benefit of the "shared lift" - the same concept Bill Roberts uses in his latest ARC 21)

3) The reefed sails in heavy weather generate the same power - but in a lower position up the mast. This configuration requires less righting moment (reduced vertical load on the foils) and is less prone to pitchpole (due to the smaller leverage arm of the sail's horizontal thrust).

I think this is enough to understand why the design features of the Catri help keep the boat controlable and with a bow up attitude all the time.

About the square tops, the same guy ordered a new set of sails - with a square top main. I don't think the square top will make that much difference in speed - I expect the difference to be relevant only in match racing conditions.

The designer says that the eliptical top is better suited for heavy weather/high speed conditions, while the square top is better in light weather.

He has doubts about the behaviour of of square tops under heavy weather and for him this weights more then the light weather/match racing advantages (for safety reasons). This is a minor issue for him, though.

The 2 ft length difference between a Tornado and the Catri 22 is almost irrelevant. The Catri is a lot wider, so the righting moment is bigger and it can carry a lot more sail then the Tornado. Also, it is relatively less draggy in top speed conditions.

It seems more appropriate to compare the Catri potential with totally airborne hydrofoil boats, like the Rave, for example. Then the 32 knots can be seen as a conservative figure.

I see the Catri as a conventional tri in light winds that automatically converts into a hydrofoil tri in stronger winds. A very smart combination!

Thanks for discussing my dream boat - your expertise is always welcome!

Best regards,
Luiz