1. What is a River Hull Length Calculator?

Definition: This calculator estimates the waterline length (LWL) of a river boat hull based on its hull speed.

Purpose: It helps boat designers and enthusiasts determine the optimal hull length for a given speed in river conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( LWL \) — Waterline length (feet)
• \( HS \) — Hull speed (knots)
• 1.34 — Constant for displacement hulls

Explanation: The formula calculates the theoretical maximum speed of a displacement hull (where hull speed in knots ≈ 1.34 × √LWL in feet).

3. Importance of Waterline Length Calculation

Details: Proper hull length estimation ensures efficient boat performance, fuel economy, and stability in river conditions.

4. Using the Calculator

Tips: Enter the desired hull speed in knots. The value must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is hull speed?
A: The maximum efficient speed of a displacement hull before wave-making resistance increases dramatically.

Q2: Why 1.34 as the constant?
A: This empirical constant works well for most displacement hulls in typical river conditions.

Q3: Does this work for planing hulls?
A: No, this formula is only accurate for displacement hulls that don't plane.

Q4: How does river current affect this?
A: The calculation is for speed through water, not speed over ground. Current affects actual speed over ground.

Q5: What's typical for river boats?
A: Many river boats have hull speeds between 5-10 knots, resulting in LWL of 14-55 feet.