1. What is the Hull Speed Formula?

The hull speed formula estimates the theoretical maximum speed of a displacement hull boat based on its waterline length. It represents the speed at which the boat's wave-making resistance increases dramatically.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• \( LWL\_boat \) — Waterline length in feet
• 1.34 — Empirical coefficient for displacement hulls

Explanation: The formula is derived from wave theory, where the wavelength created by the boat equals the waterline length at hull speed.

3. Importance of Hull Speed Calculation

Details: Understanding a boat's theoretical hull speed helps in design optimization, performance prediction, and fuel efficiency planning. It's particularly important for sailboats and displacement hull powerboats.

4. Using the Calculator

Tips: Enter the waterline length in feet. The waterline length is the length of the boat at the water surface when normally loaded.

5. Frequently Asked Questions (FAQ)

Q1: Does this formula apply to all boat types?
A: This formula specifically applies to displacement hulls. Planing hulls can exceed this theoretical maximum.

Q2: Why is the coefficient 1.34?
A: The coefficient 1.34 is derived from wave theory physics and has been empirically validated for typical displacement hull shapes.

Q3: How accurate is this calculation?
A: It provides a good theoretical estimate, but actual performance may vary based on hull shape, weight distribution, and sea conditions.

Q4: Can modern boats exceed hull speed?
A: Yes, planing hulls and semi-displacement hulls can exceed this speed with sufficient power. Multihulls and specially designed hulls can also exceed theoretical hull speed.

Q5: How does waterline length affect speed?
A: Longer waterline length generally allows for higher hull speed, as the wave-making resistance increases at a slower rate for longer hulls.