Originally Posted by Stillraining
According to the calculations then..my 64 hp Perkins should be burning 3.56 gph...It is not as far as I can tell ...but I will have to have more opportunity to check it out over time to be sure ..so far I have only ran it about 2 hours...I cant ignore this feeling in my gut telling me it will come in closer to under 1/2 of that..I will be quite surprised if it does not...as using various other engine consumptions ratios I have around here to compare it with says that calculation is all wet.
If your 64 HP Perkins was actually generating 64 HP I expect it would eat up about 3 GPH. You'll notice that during rough weather in a head wind your fuel consumption will increase even though you're running the same RPM as you always do.
In calm weather with no wind it just doesn't take all that much muscle to move a sailboat around.