1. What is Hull Speed?

Hull speed is the speed at which the wavelength of a vessel's bow wave equals the waterline length of the boat. For displacement hulls (like trawlers), this represents the maximum efficient speed before requiring exponentially more power to go faster.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

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

Explanation: The formula calculates the theoretical maximum speed of a displacement hull vessel based on its waterline length.

3. Importance of Hull Speed Calculation

Details: Knowing a trawler's hull speed helps in voyage planning, fuel consumption estimation, and understanding the vessel's performance limitations.

4. Using the Calculator

Tips: Enter the vessel's waterline length in feet. The value must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a displacement hull?
A: A displacement hull is designed to move through the water by pushing it aside rather than planing on top. Trawlers typically have full displacement hulls.

Q2: Can a boat exceed its hull speed?
A: Yes, but it requires significantly more power and becomes increasingly inefficient. Some boats can semi-plane or plane above hull speed.

Q3: How accurate is this calculation?
A: It provides a good estimate for full displacement hulls, but actual performance may vary based on hull shape, loading, and sea conditions.

Q4: Does hull speed apply to sailboats?
A: Yes, the concept applies to any displacement hull, including sailboats. The coefficient may vary slightly (1.34 is typical for powerboats).

Q5: Why is waterline length important?
A: Longer waterline lengths create longer waves, allowing higher speeds before wave-making resistance increases dramatically.