Cargo Estimation

Draft survey / hydrostatic cargo estimate

A draft survey / hydrostatic cargo estimate infers cargo mass from vessel drafts and hydrostatic information at a port call. In the estimation waterfall, draft_survey is the preferred path: it requires arrival and departure survey marks plus a matching vessel hydrostatic profile, then applies trim, water-density, and deductible corrections before comparing displacement. If those inputs are absent, Overwatch can use a hydrostatic table, a calibrated vessel curve, or a trim- and salinity-aware proxy. The legacy fallback uses draft change with a vessel-type tons-per-meter coefficient, the older draft-change proxy; it is used only when better vessel inputs are unavailable. Every result carries a method and confidence label. Why it matters for grain flows: the method hierarchy keeps weekly export tonnage estimates tied to the strongest available vessel evidence.

Read the cargo validation methodology for validation context.

See how this fits into the platform: Axiom Overwatch · pricing