: Thanks Allan, yeah, I've been playing with it a bit because
: somebody in a previous post suggested it. What Bill H said or
: was it Mike? about getting as much volume in the bow as possible
: to aleviate submarining makes sense and that may not show up in
: the program, I think this is where the experience takes over
: because my original thoughts were that it was only changing the
: sheerline a bit.

I am not convinced that the volume in the bow is the only factor that affects the tendency for the bow to submarine. Of course it is one factor, but spec surf skis have something extra to help avoid the problem. They have wings on the bow as well as a fair bit of volume.

I know that no-on would build a kayak that shape, but in theory it would be possible to have a a kayak with a very tall bow, but if it was also very thin, it would not do a lot to prevent submarining. That is partly because the extra volume in the tall bow doesn't begin to have an effect until the bow has already submerged to that depth. On the other hand, a lower bow with a lot of flare would behave a little bit like wings on the bow of a ski. After all the kayak is moving through the water and a lot of flare would provide a bit of lift.

I have paddled a Night Heron in the surf and in choppy water and I know that not only does it have a fairly high bow, but it also has quite a bit of width about a foot or so behind the bow. So the Night Heron gets a substantial amount of its volume in the bow from the part of the hull that is in the water a foot back from the tip rather than relying just on the extra volume up in the air that will help after the bow has begun to submerge. The Petrel is a bit like that too.

The amount the bow will lift running down a wave or breaking out through a wave is a bit more complicated that just looking at the height of the bow. The shape makes a difference too.