Marine Calculators

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Hull Speed
Maximum Speed of a Single-Hull Displacement Boat

Hull Speed = 1.34 * (LWL)^1/2

What's your boat's length of waterline in feet?

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Boat Speed
If your speed log is disabled, you can calculate the boat's speed by determining the time it takes for a wood chip or other floating object to pass from the bow to the stern. If you want to retrieve the object, attach a string to it.

Boat Speed = (60 (sec/min) * 60 (min/hr) * length of boat in feet) /
( 6076.1 (feet/nautical mile)* seconds for chip to pass)

How long is your boat in feet?
How long does it take for a light object to reach the end of the boat in seconds?

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Sail Area Displacement Ratio
This ratio indicates how fast the boat is in light wind. The higher the number the faster the boat.

10-15	Cruiser
16-20	Cruiser-Racer
21-24	Racer
> 24	Performance Racer

Sail Area Displacement Ratio = Sail Area / ( Displacement Volume )^2/3
Displacement Volume in Cubic Feet = Weight in Pounds / 64

What is the area of your sail in square feet?
How heavy is your boat in pounds?

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