1. What is an RC Boat Speed Calculator?

Definition: This calculator estimates the theoretical maximum speed of a radio-controlled boat based on hull type, engine power, and boat weight.

Purpose: It helps RC boat enthusiasts predict performance and compare different power setups before building or modifying their boats.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Boat speed (mph)
• \( C \) — Hull constant (unitless)
• \( P \) — Engine horsepower (hp)
• \( D \) — Boat displacement (lbs)

Explanation: The speed is proportional to the square root of the power-to-weight ratio, scaled by a hull-specific constant.

3. Importance of Speed Calculation

Details: Accurate speed prediction helps in selecting appropriate power systems, ensuring stability at high speeds, and setting realistic performance expectations.

4. Using the Calculator

Tips: Enter the hull constant (default 1.34 for planing hulls), engine horsepower, and boat displacement (including all components). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical hull constant values?
A: Common values: 1.34 for planing hulls, 1.1 for semi-displacement, 0.9 for displacement hulls.

Q2: How do I measure boat displacement?
A: Weigh the complete boat including all components (hull, motor, electronics, batteries) when ready to run.

Q3: Why is the relationship not linear?
A: Water resistance increases exponentially with speed, so doubling power doesn't double speed.

Q4: How accurate is this calculation?
A: It provides theoretical maximum speed. Actual speed may be 10-20% lower due to drag, water conditions, and hull efficiency.

Q5: Can I use this for full-size boats?
A: The formula works in principle, but scale effects make it less accurate for full-size vessels.