1. What is Hull Speed?

Hull speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. It represents the maximum efficient speed of a displacement hull before excessive power is required to overcome wave-making resistance.

2. How Does the Calculator Work?

The calculator uses the Hull Speed formula:

Where:

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

Explanation: The formula estimates the speed at which a displacement hull creates a wave equal to its waterline length, beyond which resistance increases dramatically.

3. Importance of Hull Speed Calculation

Details: Knowing a vessel's hull speed helps in voyage planning, fuel efficiency calculations, and understanding performance limitations of displacement hull designs.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Yes, but it requires significantly more power. Planing hulls can exceed hull speed by rising over their bow wave.

Q2: Does hull speed apply to all boats?
A: No, it primarily applies to displacement hulls. Planing hulls and semi-displacement hulls can exceed this speed.

Q3: How accurate is the 1.34 coefficient?
A: It's an average value. Actual values can range from 1.1 to 1.5 depending on hull shape and other factors.

Q4: Why does waterline length affect speed?
A: Longer waterline length creates longer waves which travel faster through the water.

Q5: Can you calculate hull speed in metric units?
A: Yes, but the formula changes slightly. For meters: Hull Speed = 2.43 × √LWL (meters).