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 resistance. It's the theoretical maximum speed a displacement hull can achieve without planing.

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 speed (in knots) at which a boat's bow wave equals its waterline length, creating maximum resistance.

3. Importance of Hull Speed Calculation

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

4. Using the Calculator

Tips: Enter the waterline length (LWL) in feet. This is the length of the boat at the water's surface from bow to stern. The value must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Yes, but it requires significantly more power. Some modern designs can exceed hull speed through planing or semi-planing.

Q2: Does hull speed apply to all boats?
A: No, it mainly applies to displacement hulls. Planing hulls can exceed this speed when enough power is applied.

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

Q4: How accurate is this calculation?
A: It's a theoretical maximum. Actual speed depends on hull shape, displacement, and power available.

Q5: What about multihulls?
A: Multihulls often use a higher coefficient (1.4-1.5) due to their different wave-making characteristics.