Calculation of power requirement for a boat

How to calculate the minimum power required to drive a vessel of 6 tons?

How long is a piece of string?

Displacement hull? Semi-displacement? Planing? Length? Beam?

How fast for how far? Weather? Currents?

Six tons as in 12,000 pounds?

There are many online calculators available to give you a ballpark number. Another way is to look at similar boats and see what engines they use … most are way overpowered beyond whatever the calculated minimum is because of operational or marketing reasons.

A minimally powered boat is not something you want to own. Do you want to drive a 20 horsepower car?

which type sail board is better for drive a vessel weighing more than 6 tons? How the power calculated when we use more than one outboards?

The information provided by you is very sketchy indeed, except tonnage (which one?) no boat dimensions, nothing. However, for a very crude estimation of the power required for certain speeds I refer to the picture below. Hope this helps.

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Some of these posters are like seagulls, they come flying in screeching like what, shit around a bit and are suddenly gone again…


Always torn between f-off troll and taking the poster at his word he really is trying to learn something.
Anyway that formula actually is pretty close for my boat.

Just curious, is the result more accurate with C = 38?