Well here goes... from: Chapter XIII Resistance, p. 117, "

**Skene's Elements of Yacht Design**" 8th Edition updated by F.S.Kinney. 1973

This is exactly what I was hoping existed when I commented in message 3. The little curve at the top giving an optimum Cp between 0.5 and 0.7 depending on some ratio (X axis) between 0.8 and 2.0

My questions...

- Is this graph considered "current" or has it been superceded by better understanding or been totally disproved as "having made the wrong assumptions?"
- Between the writing and graph, I can't really determine what the ratio range represents. I think it is either
**(a)** the boat speed divided by 1.34*sqrt(length between crests) or **(b)** boat speed divided by sqrt(length between crests). Which is it? - I'm also under the assumption that I replace length between crests with the LWL... because we are talking about the wave crests created by the bow and stern waves. Is this correct?