Thread: Under propped?
View Single Post
Old 03-31-2014, 11:44 AM   #61
Nomad Willy
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
Diver,
Your hull speed is 7.6 knots. 5.7 X 5.7 X1.34 = 7.63...

Best speed for economy w/o getting ridiculously slow is 3/4 to one knot slower than hull speed so a little less than 7 knots would be a good place to start.

You might consider a speed less than hull speed but faster than the point where your bow starts to rise. That may be what I've described above.

Some here have run quite comprehensive tests on their boats. Those tests could be more relevant to you w your fast SD hull. Search "fuel consumption" ect. SeaHorse for one did that on a 34' IG hull and a 220hp Cummins. His turbocharger may alter the results relative to applying them to your boat. I think you'll find others though.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote