Good advice Luiz -

interesting Irens design -
S-Cat http://www.nigelirens.demon.co.uk/scat.gif


The T foils seem suceptable to damage , but look great ,

Have any yet tryed paralell dual boards with T foils attached-- {provides two points of attachment for the base foil}- --contained within a more rectangular canted hull shape -setting the T foils on the cant towards the sail plan C E and each other on a catamaran .

They could retract but only to the hull bottom ,--unless this was combined with the similar seaplane type hull shape with the step up in the hull ,--the T foil could retract into that area ,but still have some extended side area projecting .
Or alternately a narrow displ. hull design with step area for retractable foils --a deeper bow and stern area than center hull section .
Might be an area of design pursuit .