Yanmar specs
You can get information about fuel consumption for the 2GM20F on the Yanmar Web site: http://www.yanmar.com/frames45.htm Unfortunately, this is given in grams per horsepower-hour, and is a little difficult to interpret. The optimum engine performance is at about 2800 RPM, where it consumes about 210g/hp-hr. The specific gravity of #2 diesel is about 7.6 lb/gal, so your 22 gal tank should hold about 167 lbs or 76 kg of fuel. If you were using 10 hp at cruise speed (this is just a guess) you would consume about 2 kg/hr, which would give you 38 hours of operation. Note that there has been previous discussion of this topic (see the archives) and most people report a lower fuel consumption rate in practice. The one quart per hour reported by Stephen sounds about right. That's theory versus practice for you. The difference suggests that most boats this size can cruise at less than 10 HP continuous output. If you are really ambitious, you can probably measure your actual consumption. I'm sure we would all be interested in the result. Bob E.
