1. What is Theoretical Hull Speed?

The theoretical hull speed is the speed at which the wavelength of a vessel's bow wave equals the waterline length, creating increased resistance. It represents the practical upper speed limit for displacement hulls.

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 displacement hull's wave-making resistance increases dramatically.

3. Importance of Hull Speed Calculation

Details: Knowing a vessel's theoretical hull speed helps in design optimization, fuel efficiency planning, and understanding performance limitations.

4. Using the Calculator

Tips: Enter the waterline length in feet. The value must be greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Yes, but it requires significantly more power as the boat transitions from displacement to semi-displacement or planing mode.

Q2: Does hull shape affect actual hull speed?
A: Yes, while the formula provides a theoretical maximum, hull shape, weight distribution, and other factors affect actual performance.

Q3: Why is the coefficient 1.34?
A: This empirical value accounts for the relationship between wave propagation speed and waterline length in seawater.

Q4: How does waterline length affect speed?
A: Longer waterline length allows for higher theoretical hull speed, as the wave system can be spread over a greater distance.

Q5: Is this applicable to all boat types?
A: Primarily for displacement hulls. Planing hulls and multihulls can exceed this speed with sufficient power.