Foils

As there is are increasing discussions over T-foil rudders and foils I'm curious about them, never having actually seen any in the flesh, how are the rudders attached to the transom?

 I'm assuming there is a vertically upward force created by these rudders, so the regular arrangement of pintles to drop the rudder on, with a springy clip to stop it dropping off when capsized/turtled won't work as it wouldn't an upwards load. So how's it done?

Anyone got a picture or link?

This is our rudder on the Cherub. The stock is fixed with a metal rod on which the angle of attack is adjusted. The blade is pushed down through the stock and fixed in place by the aluminium tube at the top. Thats about it really!

The rudder and Gantry on AquaMarina with the blade of the T fixed in the rudder, the stock rotates to change the angle of attack.

this is with the rudder almost full negative,. no lift for going down wind



The adjuster full positive for max lift when going up wind.



A close up of the adjuster, the rod pushes against the pintle to move the rudder stock.



One of the other ways to do it is to have the blades fo the T-foil rotate on an axle in the blade of the rudder, this is a bit trickier to make but is popular in the 14's.

Because the whole stock moves you are changing the angle of the hinge so the blade stays in the same place relative to the hinge so no change in tiller loads (at least, when the boat is perfectly upright - as soon as you heel the lift from the t-foil also has a bit of sideways component so steers the boat too...)

they heel to windward to use the tfoils as a daggerboard of sorts i believe