Anglo-French Conference on Time-keeping at Sea

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The Anglo-French Conference on Time-keeping at Sea was a conference held in London in June 1917.

History

The Conference established the

, the old practice of keeping local apparent time prevailed on many independent merchant ships.

Current usage

The nautical date line is implied but not explicitly drawn on time zone maps. It follows the

) by twelve hours is bisected by the nautical date line into two 7.5° gores that differ from GMT by ±12 hours.

In reality nautical time zones are used only for radio communication etc. Internally on the ship, e.g. for work and meal hours, the ship may use a suitable time of its own choosing. This includes fixed installations such as oil rigs. For example, the Norwegian

oil rigs are located in international water at longitude 3°E but use Norwegian time.

See also

• Marine chronometer