In a book that's hiding at the moment I have seen a hydrofoil sailing yacht that was designed and built by the US navy
(unless it was the marines or something) and there was a picture of it with the 'displacement' hull
well clear of the water
zipping along with a couple of smiling sailors in her.
So yes someone did try and succeeded. So I suppose it is practical.
The idea was that the hydrofoils gve her lift
, stability and directional stability. There was no keel
. Just these ladder - like appendages underneath, angled outwards.
The verticals presumably played the role of a centerboard
while the "horizontals" were the hydrofoils providing lift
In fact the "horizontals" were not really horizontal. They were angled rather like the dihedral of an aeroplane.
A very impressive speed was reported.