Wetted Surface Area
Enter hull dimensions and displacement to estimate wetted surface area using Denny–Mumford and Muragin approximations.
Use the Wetted Surface Area
Hull Dimensions
If unknown, enter LWL × B × T × Cb (e.g. 150 × 25 × 9 × 0.74 ≈ 24 975 m³)
Enter dimensions and click Calculate WSA
Denny–Mumford Formula
—
m²
1.7 × LWL × T + ∇ / T
Muragin Formula
—
m²
LWL × (1.36 × T + 1.13 × B × Cb)
Midpoint for Comparison
—
m²
Calculation Steps
Typical WSA for Common Vessel Types
| Vessel | WSA (m²) |
|---|---|
| 10 m sailing yacht | ~20 – 35 |
| 25 m motor yacht | ~150 – 250 |
| 60 m offshore supply vessel | ~900 – 1 400 |
| 150 m general cargo ship | ~4 000 – 6 500 |
| 300 m container ship | ~15 000 – 22 000 |
| 350 m VLCC tanker | ~27 000 – 35 000 |
Summary
Enter hull dimensions and displacement to estimate wetted surface area using Denny–Mumford and Muragin approximations.
How it works
- Enter the vessel's waterline length (LWL), molded beam (B), and mean draft (T).
- Enter the displacement volume (∇) in cubic meters or cubic feet.
- The Denny–Mumford formula computes WSA = 1.7 × LWL × T + ∇ / T.
- The tool derives block coefficient Cb = ∇ / (LWL × B × T).
- The Muragin formula computes WSA = LWL × (1.36 × T + 1.13 × B × Cb).
- Both estimates and their midpoint are displayed for comparison.
- Switch between metric (m, m³) and imperial (ft, ft³) with the unit toggle.
Use cases
- Estimate frictional resistance during early ship design.
- Calculate paint area for hull coatings and antifouling budget.
- Compare Denny–Mumford and Muragin estimates during preliminary design.
- Support preliminary powering calculations and speed-power curves.
- Validate hydrostatic software output against simple closed-form formulas.
- Naval architecture coursework and self-study exercises.
Frequently Asked Questions
Last updated: 2026-09-19 ·
Reviewed by Nham Vu