Plimsoll Mark • Summer • Tropical • Winter • WNA • Fresh Water • Tropical Fresh Water • FWA • Dock Water Allowance • Draft Margin
Load Line Freeboard & Plimsoll Mark Tool Summer, Winter, Tropical & Fresh Water Drafts
Translate the ship’s assigned Summer load line into the ordinary seasonal and fresh-water marks, visualize the Plimsoll spacing and screen the allowable draft in dock water. Simple mode derives T, S, W, WNA, F and TF plus draft margin. Advanced adds selectable FWA basis, certificate/mark-spacing cross-checks, dock-water loading allowance, planned weight change, density sensitivity and a professional load-line action board.
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Need certificate mark checks, alternate FWA basis or planned loading? Click Advanced above.Use the ship’s assigned Summer freeboard and Summer draught. This tool does not recreate the full statutory freeboard assignment from Type A/B tables and corrections.MarksTF / F / T / S / W / WNA
DensityFWA + dock-water allowance
LoadingCurrent draft margin
Assigned Summer Condition
mm from the applicable freeboard/deck-line reference to S.
m, top of keel to centre of the load-line ring.
m.
t at the Summer load waterline.
t/cm in salt water.
t/m³, 1.000 to 1.025.
Select from the certificate/voyage load-line zone assessment.
m, for margin screening.
Certificate / Assigned Summer Basis
mm.
m to centre of S ring.
m for WNA rule.
mm, used only when selected.
t.
t/cm.
mm.
Dock-Water / Loading Condition
t/m³.
m.
t; + load, − discharge. First-order TPC screen.
m remaining draft margin for WATCH status.
Physical Mark Spacing Cross-Check
Optional measured/certificate spacings from the Summer line. Enter blank to skip a check. “Above S” means physically higher on the ship’s side and therefore a deeper permitted draught.
mm.
mm.
mm.
mm. Expected 50 mm only for ships not more than 100 m where WNA applies; otherwise 0.
Load Line Planning Checks
Regulatory limitation: this tool starts from assigned/certified Summer values. It does not determine statutory Summer freeboard from the Type A/Type B tables, corrections, structural arrangements or Administration decisions. The International Load Line Certificate and the ship’s permanent marks control. Route zone/season applicability must be established separately from Annex II. Timber load lines are outside this ordinary-load-line model.