1. What is the Boat Speed Formula?

The boat speed formula estimates a vessel's speed based on its horsepower and displacement. It provides a theoretical maximum speed based on power-to-weight ratio, with the constant accounting for hull design and other factors.

2. How Does the Calculator Work?

The calculator uses the boat speed formula:

Where:

• \( Horsepower \) — Engine power output in horsepower
• \( Displacement \) — Boat weight in pounds
• \( Constant \) — Hull efficiency factor (typically 150 for average boats)

Explanation: The formula shows that speed increases with the square root of the power-to-weight ratio. Doubling horsepower only increases speed by about 41%.

3. Importance of Boat Speed Calculation

Details: Understanding the relationship between horsepower, weight, and speed helps in boat design, engine selection, and performance optimization.

4. Using the Calculator

Tips: Enter horsepower in hp, displacement in pounds, and the appropriate constant (150 for average boats). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical constant value?
A: For average boats, 150 is typical. High-performance boats might use 200-230, while heavy displacement hulls might use 120-140.

Q2: Why doesn't doubling horsepower double speed?
A: Water resistance increases exponentially with speed, so power needs to increase disproportionately to achieve higher speeds.

Q3: Does this account for different hull types?
A: The constant factor approximates hull efficiency. Planing hulls will have higher constants than displacement hulls.

Q4: What's not accounted for in this formula?
A: Factors like propeller efficiency, hull fouling, sea conditions, and wind resistance aren't included in this basic calculation.

Q5: How accurate is this formula?
A: It provides a theoretical maximum speed. Actual speed will typically be 10-20% less due to various real-world factors.