Wetted Surface - Mumford Formula
Wetted-surface estimate for displacement hulls from LWL, T and displacement. Used for quick resistance estimates when offsets are unavailable.
Wetted surface area S
8,285m²
Formula, assumptions, and limits
$$S = 1.7 \cdot L \cdot T + \frac{\nabla}{T}$$
Mumford's formula - accurate to ±3 % for typical merchant hulls. Holtrop's S-approximation (implemented inside tech-holtrop-mennen) is more accurate for bulbous or transom-stern hulls.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $L$ | Waterline length | m | ship particulars |
| $T$ | Draft | m | hydrostatics |
| $\nabla$ | Displacement volume | m³ | hydrostatics |
| $S$ | Wetted surface | m² | result |
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