Either a skeg of fin can be used on the Squirt. On
a small boat such as the Squirt, the skeg should end approx 18" forward of
the transom to prevent cavitation.
The skeg is cut from 3/4" thick material, tapers from approx 1/2" at
the forward end to 1 1/2" aft. Give the trailing edge an airfoil shape.
See drawings below from other sets of plans.