1. What is Hull Speed?

Hull speed is the theoretical maximum speed that a displacement hull boat can achieve without planing. It represents the point where the wavelength of the boat's wake equals the waterline length, creating significant wave resistance.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• \( V \) — Hull speed (knots)
• \( LWL \) — Waterline length (feet)
• \( 1.34 \) — Empirical coefficient for displacement hulls

Explanation: The formula calculates the speed at which the boat's bow and stern waves synchronize, creating maximum wave-making resistance.

3. Importance of Hull Speed Calculation

Details: Understanding hull speed helps boat designers and sailors optimize performance, predict fuel consumption, and determine realistic speed expectations for displacement vessels.

4. Using the Calculator

Tips: Enter the waterline length in feet. The waterline length is the length of the boat at the water's surface, which may differ from the overall length.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Yes, planing hulls and semi-displacement hulls can exceed hull speed by rising over their bow wave, but pure displacement hulls cannot sustainably exceed this speed.

Q2: How accurate is the 1.34 coefficient?
A: The coefficient varies slightly (1.34-1.5) depending on hull shape, but 1.34 is the standard for most displacement hull calculations.

Q3: Does hull speed apply to all boats?
A: No, it primarily applies to displacement hulls. Planing hulls, multihulls, and hydrofoils operate differently.

Q4: What factors affect actual hull speed?
A: Hull shape, weight distribution, sea conditions, and propulsion efficiency can all influence actual performance.

Q5: Why measure in knots and feet?
A: These are traditional nautical units. 1 knot = 1 nautical mile per hour = 1.15078 mph.