1. What is Hull Speed?

Hull speed is the theoretical maximum speed that a displacement hull can achieve without planing. It represents the point where the wavelength of the boat's wake equals the waterline length, creating significant wave-making resistance.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• \( V \) — Hull speed in knots
• \( LWL \) — Waterline length in feet
• \( 1.34 \) — Empirical constant for displacement hulls

Explanation: The formula calculates the speed at which the wavelength of the boat's wake matches its waterline length, creating maximum wave-making resistance.

3. Importance of Hull Speed Calculation

Details: Understanding hull speed helps RC boat designers and enthusiasts optimize hull design, predict performance characteristics, and select appropriate power systems for displacement hull configurations.

4. Using the Calculator

Tips: Enter the waterline length in feet. The value must be greater than zero. For RC boats, typical LWL values range from 1-10 feet depending on the scale.

5. Frequently Asked Questions (FAQ)

Q1: Does this formula apply to planing hulls?
A: No, this formula is specifically for displacement hulls. Planing hulls can exceed their theoretical hull speed by riding on top of the water rather than displacing it.

Q2: Why is the constant 1.34 used?
A: The constant 1.34 is derived from wave theory and represents the speed-length ratio where wave-making resistance becomes significant for displacement hulls.

Q3: How accurate is this for RC boats?
A: The formula provides a good theoretical estimate, but actual performance may vary based on hull shape, weight distribution, and scale effects.

Q4: Can RC boats exceed their hull speed?
A: Yes, with sufficient power and appropriate hull design, some RC boats can plane and exceed their theoretical hull speed.

Q5: What factors affect hull speed besides LWL?
A: Hull shape, weight distribution, hull cleanliness, and water conditions can all influence the actual speed achievable.