Deck logs and noon reports as evidence
Log-keeping standards, Voluntary Observing Ship status, propeller slip, and the ballast, AIS and ECDIS cross-checks used to discredit a log in arbitration.
The deck log and the noon report are the ship’s own record of what she did, and in a performance dispute they are the primary evidence unless they can be shown to be unreliable. The deck log records position at least every two hours, weather at least every four, and distance made good with average speed at each noon; the engine log adds revolutions, slip and fuel consumed.
The traditional London position prefers the logs, on the reasoning that mariners are recognised by the WMO as trained observers recording conditions at the ship’s actual position. The full article will cover log-keeping standards and what good practice looks like, Voluntary Observing Ship status and why it matters, propeller slip as a current indicator, and the cross-checks against the ballast log, the stability computer, AIS and ECDIS by which a log is attacked.