HEre's another data point:
In Insatiable one, a 36 ft ex IOR one-tonner with a 35 hp BMW we logged an average of around 300 hours per year, full time cruising. During those 17 years we did 86,000 miles. That engine
consumed around 1.5 to 2 l/hour depending on how dirty the bottom was and so on. So, <600 litres per year. No gen set, but some charging
using the main engine (small solar
plus at-anchor wind
Since we sold I-one and bought I-two (46' performance type boat
, 43 hp Nanni, no gen set, diesel heater
, adequate solar
for most places plus Air-X wind gen) we have done slightly less miles/year: 39,800 in 8 years. Still use the engine around 300 hours/year, but this one uses 2 to 2.5 l/hr, so we use around 6 to 700 litres per year, including some heating
Our sailing style emphasizes sailing over motoring, but when cruising the East coast
there are lots of barred entrances that require timely arrivals, and so we find we motor
somewhat more there than in general.
Hope that this helps in your decisions .