Re: SOT Hull Shape?

Posted by Kurt Maurer on Aug 28, 2006

Here's the deal: To make a SOT work, you must raise the paddler's fanny at least to the waterline, or preferably, a little above it, in order for the scuppers to drain the cockpit. Otherwise, it's gonna be a matter of sitting in a bathtub, and that ain't gonna fly with too many folks.

But when you raise the paddler up, you run into a serious stability problem. In short, the center of gravity is high, and so the boat becomes mighty tippy. To recover the lost stability, adding to the boat's beam is the obvious answer; but if the designer performs a little fancy footwork with the hull shape, he can keep the beam increase minimal.

Also, a wide, flat bottom provides maximum primary stability, but it's really lousy at handling waves. A rounded or vee-bottom shape handles waves well, but has less inherent stability.

The CLC/Schade SOT hull has a nice little compromise going, where a vee runs down its center to deal with waves and maximize tracking, while sponson-like, highly exaggerated chines are provided to deal with side to side tipping moments. It's not perfect, but then, no one small boat design's assembly of compromises is, or ever will be.

This is why I don't care for the SOT too much; by its very nature, it has a ton of built-in inefficiency, and there's just no way around it unless the paddler is willing to deal with a very demanding boat -- behold: the Surfski, which is basically what you'd get if you made a SOT out of a Ch16. Which, now that I think about it, sounds kinda cool after all! Only make mine more like 19' x 17" (!), more typical of a surfski.

All this is simply the price you pay for being able to clamber aboard or hop out so easily (I'm really not so sure what the idea with surfskis is, but I'm sure someone will soon straighten me out on it). Incidentally, a few SOT's were designed kinda nicely, if an efficient hull is what you call nice (the Perception Prism for instance), but they were largely dropped because people consider 'em unstable.

Cheers, Kurt

In Response to: SOT Hull Shape? by John S. Short on Aug 28, 2006