On 5-Jun-2004, (William R. Watt) wrote:

I think you'd better take another look at what I wrote. Hard chined boats
do have a bit more wetted surface but the turbulence at the hard chine has
a bigger effect, moreso as speed increases. (Lapped strake boats have the
same increase in resistance.)

The difference between hard and rounded chine in practice is negligible - at
least for kayaks. You'd have a hard time finding two kayaks that have a
difference that you could attribute to the chines and could also feel the
difference.

Interestingly, and contrary to what yoru
write above, a spherical hull does nto have the minimum wetted surface.
That's because only part of the shpere is immersed, ie. a chord of the
circle. John Winters (www.greenval.com/winters.html) has some diagrams to
illustrate this. I thought as you did until I saw his examples.

You'll have to be more specific. I looked at all the pages and figures and
can't see anything that specifies the characteristics of a spherical hull.
He has circular cross sections, but not spherical hulls.

If the spherical hull does not have the least surface to volume ratio,
please tell us what shape does.

Mike