Cruising revs you should get 1 litre per hour. Speed will be dependant
on conditions. Flats ea and no tides or winds should get 5 knots easily.
I have been down to a couple of knots when wind and tides conspire
What size prop do you have on your Beta - Mine's a 12x8 but feel a 12x9
might be a better choice (I could be wrong), is there any one out there
with experience of this? A few weeks ago I motored at ~4.5-5 knots for
14 hours (not a breath of wind) on just over 10-12 litres of fuel.
Might be able to meet Fri night, but have commitments Sat afternoon so would
have to leave at lunch.
Will call you
PS - Word of advice for anyone fitting a new mast to a VEGA. Fill the hole
that the wires go through. I didn't and now have to lift the mast again as
every time it rains water pours down below - New mast has the halyards etc
running inside, not like the original.
In line with what written by Steve and Metacentre, my Vega, equipped with the Volvo MD7A and the original Volvo Combi system (2 blades feathering prop) on a flat sea without current, was consuming 1L/hour at 5 knots and 0.7L/hour at 4 knots. Now I have installed the Beta 14 but I have not yet tried it.