Originally Posted by JIY
Sorry to sidetrack this thread, but I'm a little stunned at the fuel consumption figures quoted here. My 8.5m Tornado with 250hp Yanmar burns just under 6gph marine diesel at 33 knots (that's a little under one litre/nautical mile), with 4 people aboard, a full 200 litre tank and slight/moderate seas. I reckon the boat weighs a little over 2 tonnes with this load.
I am equally surprised by some of the fuel consumption figures claimed by the diesel users. My, admittedly limited, experience indicates that a performance diesel boat uses more fuel that its petrol equivalent.
I was reminded today about a trip we did to the Class 1 powerboats at Plymouth last Summer. The Scorpion (with O/B Honda 225) and a Revenger 29 (with inboard Yanmar 300 diesel) met up close to Poole and cruised together to Dartmouth with similar fuel loads of approx 300 ltrs. When we left Dartmouth the Revenger was nearly empty and needed refuelling. The Scorp still had about 120 lites left.
Hardly scientific I know, but that's the way it was.