1. What is Hull Speed?

Hull speed is the speed at which the wavelength of a vessel's bow wave equals the waterline length, creating increased drag. For full displacement hulls, this represents the theoretical maximum efficient speed.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

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

Explanation: The formula calculates the speed (in knots) at which a displacement hull's wave 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 calculation.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Displacement hulls can exceed hull speed but with exponentially increasing power requirements. Planing hulls can exceed it by rising over their bow wave.

Q2: Does hull speed apply to all boat types?
A: No, it primarily applies to full displacement hulls. Semi-displacement and planing hulls have different performance characteristics.

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

Q4: What affects a boat's waterline length?
A: Loading, trim, and hull design all affect LWL. It typically increases when the boat is heavily loaded.

Q5: Can hull speed be increased?
A: Only by increasing waterline length (through design changes) or changing to a different hull type.