1. What is the Boat Speed Formula?

Definition: This formula calculates a boat's theoretical maximum speed based on its power and displacement.

Purpose: Helps boat designers, owners, and enthusiasts estimate speed potential and compare different boat configurations.

2. How Does the Formula Work?

The calculator uses the formula:

Where:

• \( S \) — Boat speed (knots)
• \( C \) — Hull speed constant (typically 1.34 for displacement hulls)
• \( P \) — Engine power (horsepower)
• \( D \) — Boat displacement (pounds)

Explanation: The formula shows that speed increases with power but decreases with the square root of displacement.

3. Importance of Boat Speed Calculation

Details: Understanding this relationship helps in selecting appropriate engines, estimating fuel consumption, and comparing boat designs.

4. Using the Calculator

Tips: Enter the hull constant (default 1.34), engine horsepower, and boat displacement in pounds. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical value for C?
A: 1.34 for displacement hulls, 1.1-1.3 for semi-displacement, and lower for planing hulls.

Q2: Does this work for all boat types?
A: Best for displacement hulls. Planing hulls exceed these theoretical speeds.

Q3: How accurate is this formula?
A: It provides theoretical maximums - actual speed depends on hull design, load, and conditions.

Q4: Can I use this for sailboats?
A: Yes, but use sail area instead of horsepower for wind-powered calculations.

Q5: What units should I use?
A: Consistent units are critical - horsepower (hp) and pounds (lbs) for this calculator.