Originally Posted by rpoint16
I have been on multiple day trips on a Cal 39, Bennatue 37, & a Catalina 32, and compiled probably 15 hours each trip of motorsailing. It seems on each boat during refueling it averages about 1 gal of diesel to 1 hour of motoring. Is that a "ballpark" standard of consumption?
Using Gerr's formulas, assuming 5kt boat speed, assuming a 3000lb load on the boat and no sails
The Cal should get about 7.0 nm/gal depending on model
should get 7.5-7.8nm/gal depending on model
The Catalina should get 8.2 nm/gal.
Given that you were using significantly more fuel than this with sails
up for all these boats I suspect:
A) You are maintaining a high throttle setting,
B) the engines all have problems,
C) the bottoms are all significantly fouled,
D) some combination of the above,
E) something is affecting all these boats that I haven't thought of.
Here is the link to the calculator that I figured out all the formulas from.
Boat Speed Calculator