Went to Tangalooma the other day from Manly boat harbour and just worked out my fuel consumption figures, which i found pretty amazing.
Specs
17 foot fibreglass cuddy,
90 Hp Tohatsu carby 2 stroke,
5 Adults on board+ esky,
Distance covered 80 km
Fuel used 35 litres
Approx 2.28 km/litre
Cruising at 4400 rpm
17 pitch ss prop.
Approx 26 knots.