RE: Fuel Consumption 0f Crusader Marine 502XL
Your boat will take only high idle at that speed, not much fuel as gas is fine at being efficient at almost no power.
Finf out the weight of the boat in pounds and divide by 2240. That is the weight in Tons.
2 or 3 hp per ton should cruise you and the engine will make about 10 hp from each gallon of gas.
A boat that is designed to operate fast may stink at helm commands at low speed due to small rudders.
Also there may be a huge lack of a seakindly ride , due to the low speed.
Every boat is different , when removed from its built operating regime , a sea trial would be required.
Avoid a wallowing pig boat , regardless of the price , unless its selected as dock condo .