keeping it semi circular would give the minimal wetted area and make it easy to do mold frames without CAD.
My proposal for the 16ft hull

max width 13.5 inch tapering to 1.5 inch at the bow and 10.75inch at the transom...

hull would be 19 inch high at the bow, 24 inch amidship and 14inch at the transom.

Max depth and height would be 5ft from the stern, coinciding with the middle of the daggerboard.

Would that work?

Shane

PS I can imagine using 24inch wide PVC foam... its quite stiff, how wil it conform to the curves of the hull....unless you have a female frame and apply heat while vacuuming it