My Bavaria34, Saloma has a Volvo D2020 engine with the original 2 blade prop. We have had the boat from new, christmas 2001 and cruise extensively. We run the engine at 2400/2600 RPM and find that fuel consumption works out at 1.5 lts/hour.
This figure has been so consistant that we use it to calculate how much fuel it is likely to take to fill the tank.The fuel gauge is simply not accurate enough to indicate when the tank is full and we try to avoid any spillage. Engine hours run since tank last filled multiplied by 1.5 has always proved an accurate number to within a litre of what has been required to refill the tank.
We have a tank capacity of 90 ltr and carry 2x 10 ltr cans = 110 ltr. We work out our range as 110 divided by 1.5 multiplied by 5 knots = 366 Nautical miles. With sailing this always seems sufficient to cover a minimum cruise distance of 700 plus.