Mast or Keel is what I've heard most, also manufacturers, use.
Mast is a bit confusing, i admit...
I went through the topic I got some findings.
Why do we not use a sailing vocabulary? Instead we use aviation one.
I thought foilboarding is about sailing seas rather than flying skies
Check it out:
A fuselage is a main body of a plane.
A main body of a vessel is a hull.
Have you ever seen a sailing unit having a mast under water? Actually I've had - once they were sinking.
Whatever appendage of sailing unit got it is called a fin or a keel.
A keel of vessel from a structural point of view is is a beam around which the hull of a ship is built.
A fin is a thin component or appendage attached to a larger body or structure.
On Polish forum I created a topic with FAQ and proposed to Poles to use maritime expressions. Check out Question No.4:http://www.foilforum.pl/viewtopic.php?f=2&t=83
I've been trying to convince Poles to use:
- a fin (our masts, struts (building roofs?), keels, T-bars)
- a keel (our fusalage) ,
And I think not too many buys it.
Most of users talks about planes, hydroplanes, masts.
Should I give up with idea to understand it as a sailor?