1. What Is Hull Speed?

Definition: Hull speed is the theoretical maximum speed a displacement hull can efficiently travel through water without excessive energy expenditure.

Purpose: It helps boat designers and sailors understand the speed limitations of traditional boat designs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HS \) — Hull speed (knots)
• \( LWL \) — Waterline length (feet)

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

3. Importance of Hull Speed Calculation

Details: Understanding hull speed helps in boat design, fuel efficiency planning, and performance expectations.

4. Using the Calculator

Tips: Simply enter the waterline length of your vessel in feet. The value must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does the 1.34 factor represent?
A: This empirical constant relates waterline length to wave-making resistance, derived from observations of displacement hull behavior.

Q2: Does this apply to all boats?
A: No, this only applies to displacement hulls. Planing hulls can exceed this speed with sufficient power.

Q3: How do I measure waterline length?
A: Measure the length of the boat at the water's surface from bow to stern when normally loaded.

Q4: Can boats exceed hull speed?
A: Yes, but it requires exponentially more power and may be inefficient for displacement hulls.

Q5: Does hull speed change with weight?
A: Indirectly, as added weight may increase waterline length, which would increase hull speed.