1. What is the Hull Speed Formula?

The Hull Speed formula estimates the maximum efficient speed of a displacement hull boat based on waterline length and Crouch constant. It provides a theoretical maximum speed before wave-making resistance becomes excessive.

2. How Does the Calculator Work?

The calculator uses the Hull Speed formula:

Where:

• \( v \) — Boat speed in knots
• \( C \) — Crouch constant (150-220)
• \( LWL \) — Waterline length in feet

Explanation: The formula calculates the theoretical hull speed where wave-making resistance increases dramatically, limiting further speed gains without disproportionate power increases.

3. Importance of Hull Speed Calculation

Details: Understanding hull speed is crucial for boat design, performance prediction, and engine selection. It helps determine the practical speed limits for displacement hull vessels.

4. Using the Calculator

Tips: Enter Crouch constant between 150-220 (typical values for different hull types) and waterline length in feet. Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the Crouch constant range?
A: The Crouch constant typically ranges from 150 for heavy displacement hulls to 220 for high-speed planing hulls.

Q2: How accurate is this calculation?
A: This provides a theoretical maximum for displacement hulls. Actual speed may vary based on hull design, weight, and sea conditions.

Q3: What is waterline length?
A: Waterline length (LWL) is the length of the boat at the waterline, not the overall length. It's a key factor in hull speed calculation.

Q4: Can boats exceed hull speed?
A: Yes, planing hulls can exceed hull speed by rising over their bow wave, but displacement hulls cannot efficiently exceed this speed.

Q5: How does horsepower relate to this formula?
A: While this formula calculates theoretical maximum speed, actual speed depends on available horsepower to overcome resistance at that speed.