View Single Post
Old 09-29-2018, 01:47 PM   #4
DavidM
Valued Technical Contributor
 
DavidM's Avatar
 
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,785
Joel:


Theoretical hull speed (it is theoretical as it is the speed at which the hull matches the bow wave) of that boat, assuming a 37'waterline is 1.34*sqrt(37) or a little more than 8 kts. Semi displacement hulls take about 2-2.5 hp per thousand pounds of displacement to reach hull speed as a rule of thumb. Your displacement is about 25,000 lbs with fuel, water and passengers. So it takes 50-60 hp. Those engines make about 17 hp per gph at low power. So it burns 50/17 to 60/17 or 3-3.5 gph for both engines.


All of the above is based on rules of thumb, but they should be good to 10-15%.


Those engines will last almost forever at that low power output. But push it to 15 kts and they won't.


So go slow.


David
DavidM is online now   Reply With Quote