Hull speed

The tunnels also cause loss of lift and more turbulence. I think that the only real advantage is less draft.

 

It is certainly two sided process: something you win, something you lose.
Properly designed tunnels do not cause turbulence, by the way.


The break point could be the required amount of lift -the deeper in pure planing area you are, the more important the lift becomes.

 

@ Perm Stress: The equation you posted ~10-13kW/t, does t=ton(s)? Does that equation have a name?

Thanks for your response to my above questions =)

 

Yes, t mean tons.
The equation has no name really.
A while ago I did statistical analysis of published data for various motor yachts; comparison between installed power and Froude number, based on quoted max speed was made.
It was necessary to decide on ballpark figures for speed and power of large motor yacht design.
At limit semi-planing/planing there was 10-13kW installed power per ton of quoted full displacement. That's all.
P.S.
all the data used for analysis as published:
published max displacement
nominal power of engines

 

Spreadsheet question

I have a question about the spreadsheet Mike D. submitted a few years ago; what function does the single/twin engine input provide? It seems as though the internal equations are for single engine applications only. Am I wrong?