Steve,

The question that comes to my mind is: Do you plan to sew your own sprayskirt? If not, then check around and see what the circumference is at the point where your chosen sprayskirt fits over the cockpit coaming. This should be your determining factor. You may want to make your cockpit a tad bigger or smaller, more egg or oval shaped, or some odd size (say 34 1/4 inches) just to insure a snug fit with an off-the-shelf sprayskirt. Making a cardboard mock up is a good idea.

Don't forget that the walls of the coaming have some thickness, so the spray skirt would have to go over the outside dimension, and you would go into the inside dimension. Cut the hole to suit!

Of course if you are making your own sprayskirt then your design has fewer limitations.

Paul G. Jacobson