1. What is Hull Speed?

Hull speed is the theoretical maximum speed a displacement hull can achieve without planing. It's determined by the waterline length of the boat and represents the point where the wavelength of the boat's wake equals the waterline length.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• 1.34 — Empirical constant for displacement hulls
• Waterline Length — Length of the boat at the waterline in feet

Explanation: The formula calculates the speed at which the wave created by the boat is exactly as long as the boat itself, 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 displacement hulls.

4. Using the Calculator

Tips: Measure your boat's waterline length accurately in feet. This is the length of the hull that's actually in the water when normally loaded.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Displacement hulls can't exceed it without planing. Semi-displacement hulls may exceed it with enough power, and planing hulls easily exceed it.

Q2: Does hull speed apply to all boats?
A: No, it only applies to displacement hulls. Planing hulls (like speedboats) can go much faster by rising up on top of the water.

Q3: How accurate is this calculation?
A: It provides a theoretical maximum. Actual speed depends on hull shape, weight, sea conditions, and engine power.

Q4: Why 1.34 as the constant?
A: This empirical value accounts for typical wave-making resistance characteristics of displacement hulls.

Q5: How does beam affect hull speed?
A: The formula doesn't account for beam (width), but wider beams generally create more resistance, potentially reducing actual speed below theoretical hull speed.