Operational sea trial

An operational sea trial demonstrates the ship in its intended working role rather than only proving contract speed and power, run for charter acceptance or for mission-system sign-off. For an offshore vessel it exercises the DP station-keeping and the capability plot against measured wind and current, the deck and crane operations, and the fire-fighting or ROV spreads; for a specialized ship it proves the cargo, pumping, or process systems under load. The charterer or end user witnesses the trial against the acceptance criteria in the charter or supply contract, which can be stricter than the builder’s guarantee. Failure to meet a criterion delays on-hire rather than delivery.