Waterplane Coefficient (CWP)

Compute CWP directly from waterplane area, from station breadths via Simpson, or from polygon points. Includes an empirical sanity band.

AWP = 100·TPC/ρ (draft-specific).
Result

AWP = — m²

CWP = —

Enter inputs to compute.
Report: Waterplane Coefficient (Direct)
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Equal spacing along LWL.
Result

AWP (Simpson) = — m²

CWP = —

Enter LWL, BWL, stations & values.
Report: Waterplane Coefficient (Stations→Simpson)
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We apply the shoelace formula. For half-outline, we mirror about centerline.
Result

AWP (polygon) = — m²

CWP = —

Paste coordinates to compute.
Report: Waterplane Coefficient (Polygon)
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Empirical / Sanity

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Use as a sanity check. CWP depends on hull planform & draft.
Report: Waterplane Coefficient (Empirical)
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Tip: Use LWL & BWL at the same draft as your waterplane. CWP should be in (0, 1).