I have my gauges set to show l/nm not l/h, personally I think that fuel/distance is more meaningful than fuel/time. So I'm not 100% sure of my consumption/hour, so....
@ 3800rpm i'm doing around 28kn & 0.65nm/l =comfortable cruising speed.
@ full chat 5750rpm I'm doing 45kn & 0.5nm/l =teeth rattling
The best I can get is firstname.lastname@example.org/l on calm water, lightly loaded & fully trimmed up.= zzzzzzz!
So there is a 50% difference between best & worst, extrapolating the figures gives about
90l/h worst case & 33l/h best case, "Normal" cruising i'm doing around 43 l/h which I don't think is too bad with twins.
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: See rule#5