Originally Posted by riverfrontauthor
I have a 73 Gulfstar 43 with twin Perkins 135s. Running one screw at 1500 I'll get 6-8 kts and burn 3.5 gph.
HOWEVER, running two screws, each at 1500, I'll get 8-10 kts and burn 2.5 gph.
Yes, I burn less diesel on two screws than I do one...
I gave up trying to figure out torque curves and angle of the rudders and just accept that Lucky wants to run on two screws
Sorry it's been a while but:
When I took the boat to Florida. Very rough conditions. 12' + in the Gulf Stream but the worst was from New providence to Chubb 4' to 8' 3 points off the Stbd bow. Wet wet wet
Anyway the fuel usage for 24hours (this was over a 3 day cruise. Roughly 8 hrs running a day) came out to approx. 180g. (dirty Bum and props)
We were running hard. The engines did not miss a beat. Considering the boat probably hasn't done anything like that in the last 15 years. It was impressive.
In Lauderdale I had the Fuel pumps professionally overhauled. Props and bottom done.
On the run back conditions were a lot smoother to say the least and the fuel burn:
running at 1,600 for most 2/3 of the way and 1,800 for the other 1/3
So that is pretty well spot on what you are getting.
Very happy indeed!