> Hull speed is not an insurmountable speed limit. Long narrow boats can
> often be propelled beyond hull speed. Planing boats all exceed hull speed.
> Instead hull speed tells you when the waves produced by the hull have the
> same length as the hull. In most cases this will mean the boat becomes
> much harder to propel any faster.

I agree. That is why I qualified my answer by saying that it applied to "displacement hull types." There are, in fact, many ways to make even displacement hulls more efficient. The flat sterns seen on large ships create a hull wave that behaves as if it were generated by a longer hull. Thus, helping to overcome the "theoretical hull speed." I have noticed some newer kayak hulls incorporating this flat stern. Nick, do you think this adds any significant performance increases in a kayak design? My naval architecture experience is limited to larger hull forms.