: I've been playing with a surfski design at 20 feet long. Just for
: fun I shortened it to 16.5 feet (to sneak into a local race in
: the "recreational" class)

: According to Kayak foundry the drag is nearly identical in my
: target speed (6 knots) and the drag is far less at speeds under.
: I'm not surprised at the the lower speeds, but I would have
: thought that the 6 knot drag would have been significantly
: higher.

: The stability took a huge turn for the worse... but I can live with
: tippy.

: Am I missing something? In the real world, can I take my surf ski
: plans and build a shorter ski and eat my cake too???

: Rob

It seems to be a common theme in the responses that you can make a longer boat go well if you have the power. If not you should find out how much power you have and build to that with some expectation of how much you intend to improve.

I think it's interesting that international surfski racing has no limit to boat length or width (that I know of) and they settle on 21 feet x 17" plus or minus a bit. There are probably marketing pressures considered otherwise the larger elite paddlers would probably design custom 23' x 15" surfskis. There aren't any yet so that tells me the surfski dimensions are close to optimized.

For me 21 feet is too long for anything but a short sprint and I hear of quite a few good paddlers winning races with 19 foot x 19" so called beginner surfskis. In local races if a K-1 (17'?) survives the waves they always outsprint the longer surfskis which is counter intuitive but the surfski paddlers don't have the power to take advantage of the waterline after 10 km of racing.

There seems to be gap in availability of commercially available short and narrow boats (19' x 17").

My unfinished strip surfski is 21' x 18" and i wish it was 19' so you're on the right track in my opinion. I haven't even paddled it yet but I'm sure it's too long. (Vancouver = less swell than Bellingham).

With respect to Bill Hamm's comment about 'sit on tops' placing the paddler above the water line you'll find the seats are only about 1/2" (1cm) above the keel (I measured) so Surfskis with a lot of rocker actually put the paddler deeper than a minimal rocker boat. I think that explains how they stay upright.

I raised my seat to 1" above the keel to keep my butt above my feet but my boat is beamier and flatter than most surfskis so it may be OK.

I like this discussion. I hope some designers with some racing experience give their opinions.