Gero

We felt in testing that in gusty conditions the T-foil equipped boat was less 'flighty', in other words it was less prone to violent hull lifting in gusts, this is dificult to measure and was more a feeling, we put it down to the following effect.

When hit by a gust the non t-foil boat would accelorate at the same time as the hull lifted, this extra drive produces a small dip as the bows go down under acceleration.

On the T-foil equipped boat the bows don't dip because the T-foils hold the boat steady, but of course to do this they apply downforce , also as the rudder lifts it is no longer travelling horizontally but is sloping up, these 2 effects produce downforce on the rudder which on the windward one equates to an extra force resisting hull lift.

The net result of this is that it is just as easy to fly a hull and the same wind strength is required to do it either way, it is just that it dampens the effect of gusts, and lulls(because the reverse happens then).