Unmooring

Unmooring refers to the operation of a vessel releasing its mooring lines and departing from a berth, a key milestone in voyage execution. In foreign trade and shipping, unmooring time is directly linked to cargo loading completion, bill of lading issuance, freight calculation, and risk transfer (e.g., under FOB, risk transfers from the ship's rail or on board at the port of shipment). Use cases include: laytime and demurrage calculation in charter parties, proof of shipment date required by letters of credit, and commencement of insurance. Notes: unmooring is not the same as departure; a distinction must be made between 'unmooring' and 'departure' from port. After unmooring, the vessel may shift berth or anchor, so the bill of lading date is usually based on completion of loading, not unmooring time. Opposite to 'berthing,' unmooring marks the end or beginning of a voyage. In practice, attention should be paid to written records of the unmooring fact (e.g., unmooring certificate, ship's log) to avoid disputes between buyer and seller over shipment time.