As it was to wet to go out today I've been calculating my fuel consumption this season.
My figures give 0.73litres/NM or 1.37 NM/ litre.
This on a Suzi 4stroke 100hP mix of pootling arond at displacment 5-6kts in the river & cruising ant average of 27-27 knot, 2 adults 2 children on board, mix of sea conditions. This is better than I expected.
Sounds right to me. Based on other threads, leisure users quoting figures, so some pootling and some cruising and personal use, a 135/150hp on a 6m gives broadly 1L per mile. A bit smaller boat and engine will give just under and less the smaller you go and vice versa.
That being for a modern 2 stroke (post about 2002) or 4 stroke.
Subject to your load/type of use and balance of engine/boat. A 75 on a 6m is going to be at WOT all the time so probably use more than a 115/135 perhaps.
