Vetus M3.10 inboard diesel engine running at idle HD

The Vetus M3.10 is a Dutch marinized Mitsubishi 3 cylinder, 24 h.p., fresh-water cooled, inboard diesel marine engine. This one has been installed in a 1977 Pearson 28 sailboat. It will burn about half a gallon of fuel per hour at its cruising speed of about 2,200 r.p.m., pushing the boat at 4.5 knots, with WOT at 3,300, pushing the boat to hull speed of 6.5 knots.