Water Displacement Calculator Boat Trader

Displacement Formula:

\[ Displacement = Length \times Beam \times Draft \times Block\ Coefficient \times Density \]

Length:

Beam:

Draft:

Block Coefficient:

Density:

lb/ft³

Displacement:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Water Displacement?

Water displacement refers to the weight of water displaced by a boat's hull, which equals the weight of the boat (Archimedes' principle). It's crucial for understanding a vessel's buoyancy, stability, and carrying capacity.

2. How Does the Calculator Work?

The calculator uses the displacement formula:

\[ Displacement = Length \times Beam \times Draft \times Block\ Coefficient \times Density \]

Where:

\( Length \) — Boat length in feet
\( Beam \) — Boat width in feet
\( Draft \) — Vertical distance between waterline and bottom of hull in feet
\( Block\ Coefficient \) — Hull fullness ratio (0-1)
\( Density \) — Water density in pounds per cubic foot

Explanation: The formula calculates the volume of water displaced and multiplies by water density to get weight.

3. Importance of Displacement Calculation

Details: Displacement helps determine a boat's load capacity, stability, and performance characteristics. It's essential for safety and proper boat design.

4. Using the Calculator

Tips: Enter all dimensions in feet. Typical block coefficients range from 0.5 (moderate hulls) to 0.8 (full hulls). Fresh water density is 62.4 lb/ft³, salt water about 64 lb/ft³.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between displacement and weight?
A: For floating objects, displacement equals total weight (Archimedes' principle). The calculator finds displacement which equals the boat's weight.

Q2: How does block coefficient affect displacement?
A: Higher block coefficients (fuller hulls) displace more water for the same dimensions, indicating greater carrying capacity but potentially slower speeds.

Q3: Why does water density matter?
A: Salt water is denser than fresh water, so boats float higher in salt water. Accurate density values ensure precise calculations.

Q4: Can this be used for any boat type?
A: Best for displacement hulls (not planing hulls). The formula assumes the hull is fully submerged to the waterline.

Q5: How accurate is this calculation?
A: It provides a good estimate but actual displacement may vary based on hull shape, appendages, and load distribution.