We’ve just finished filling our fuel tanks in Ensenada, Mexico (US$2.40/gallon). Since last fueling in Alaska we have put 422 hours on the engines, 34 hours on the genset, and used the diesel heater.

Wind Horse took 2412 US gallons, filling all six basement tanks and both engine room day tanks to the top. Calculating fuel burn over a long period is at best a rough approximation. You have the engine running at different speeds, including idling in and out of port, auxiliary requirements, and the diesel heater, the consumption of which varies greatly.

We know the genset burns about three liters (0.75 gallon) per hour. We figure that the heater ran for a month in Alaska at four gallons per day, another two months at two gallons a day, and another month at one gallon per day. With a couple of other corrections we get to a consumption for the engine of 2150 gallons. Divide this by the 422 hours and you get just a hair more than five gallons per hour. This is a lot less than in the past and reflects several changes.

First, we averaged about 10.5 knots rather than our usual 11 knots. This is more efficient. Next, we were fortunate in that most of this passaging was done in calm winds or with the wind behind us. Finally, we are seeing some benefit from the latest props, installed a year ago.

We are on our way to Panama as this is being written, roughly 2800 miles. We are not sure yet if we will stop on the way there, or go straight. Either way, it will be really good fuel burn test.