: I made a 6.5 m skin on frame potential racing boat. It was ok, but
: not the magic silver bullet I was hoping for interms of water
: line length just equals speed.

: Half the problem was weight. I believe I can make substantial
: weight savings by triming my lumber and shorting the length ...
: there is an economy in weight (if nothing else) in shorter
: boats.

: So the long term plan is to re-jig the frame aiming for 20ft.

: Moral of the story .... big is not always best.

: Cheers Pete

BY shortening a surfski down to 16.5 feet you should have a fast flatwater racer much like a beefy K1. You won't have a great ocean going surfski though. Even 20 foot is at the shorter, entry level length for a ski e.g Epicv10sport/FennXT.
I'm making an assumption that you already paddle surfskis so I'm probably not saying anything you don't already know. Will be interested to see your ski design as i know of at least one other KF designed ski being built and I hope to start mine eventually.
cheers, Boof head