1. What is Hull Speed?

Hull speed is the theoretical maximum speed a displacement hull can achieve without planing. It's determined by the waterline length of the boat and represents the point where the wavelength of the boat's wake equals the boat's waterline length.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• \( LWL \) — Load waterline length (feet)
• 1.34 — Empirical coefficient for displacement hulls

Explanation: The formula calculates the speed at which the wavelength of the boat's wake equals the boat's waterline length, creating maximum wave resistance.

3. Importance of Hull Speed Calculation

Details: Knowing a boat's hull speed helps sailors understand performance potential, fuel efficiency, and the point where additional power becomes less effective.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Yes, with sufficient power, some boats can exceed hull speed by planing or through wave-piercing designs, but most displacement hulls cannot.

Q2: How does hull shape affect hull speed?
A: Finer hulls with less wetted surface can often approach hull speed with less power, but the theoretical maximum remains the same.

Q3: Why is the coefficient 1.34?
A: This empirical value accounts for typical wave-making resistance characteristics of displacement hulls in salt water.

Q4: Does hull speed apply to multihulls?
A: Multihulls often exceed traditional hull speed calculations due to their different hydrodynamic characteristics.

Q5: How does loading affect hull speed?
A: Increased loading lengthens the waterline, potentially increasing hull speed, but also increases displacement and drag.