For a
displacement boat, the
maximum efficient speed that a particular hull can attain is called
hull speed.
It can be calculated by the formula:
Hull Speed = 1.34 * sqrt(LWL)
Where:
Hull Speed is measured in
knots, and
LWL is the
length at the waterline of the hull in
feet.
For example, a boat with a
waterline length of 500 feet
would have a hull speed of:
1.34 * sqrt(500)
= 30 knots
To achieve this
speed, a boat needs
power of approximately
2-3
horsepower per
ton. To exceed hull speed, a boat
needs 50-100 horsepower per ton.
If the 500 foot boat above weighed 10000 tons, it would
need about 30000
horsepower to travel at 30
knots.
To go faster than 30 knots, the boat would need more than 500000 horsepower.