Boat Speed Formula:
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Definition: This calculator estimates a boat's maximum speed in knots based on hull type, engine power, and boat weight.
Purpose: Helps boat designers, owners, and enthusiasts estimate potential speed based on key performance factors.
The calculator uses the formula:
Where:
Explanation: The formula shows that speed increases with horsepower but decreases with heavier displacement.
Details: Understanding potential speed helps in boat design, engine selection, and performance optimization.
Tips: Enter the hull constant (1.34 for displacement hulls, higher for planing hulls), engine horsepower, and boat displacement. All values must be > 0.
Q1: What's a typical hull constant value?
A: 1.34 for displacement hulls, 1.5-2.0 for semi-displacement, and up to 2.5 for planing hulls.
Q2: How accurate is this calculation?
A: It provides theoretical maximum speed; actual speed depends on hull design, water conditions, and load.
Q3: What affects boat displacement?
A: Hull material, fuel, water, provisions, passengers, and equipment all contribute to total displacement.
Q4: How does speed change with horsepower?
A: Speed increases with the square root of horsepower - doubling HP increases speed by about 41%.
Q5: What's a good speed for a cruising sailboat?
A: Typically 5-8 knots under power, depending on size and hull design.