The device is unlikely to have been intended for navigation use because:
1. Some data, such as eclipse predictions, are unnecessary for navigation.
2. The harsh environment of the sea would corrode the gears in a short period of time, rendering it useless.
On 30 July 2008, scientists reported new findings in the journal Nature showing that the mechanism tracked the Metonic calendar, predicted solar eclipses, and calculated the timing of the Ancient Olympic Games.[13] Inscriptions on the instrument closely match the names of the months on calendars from Illyria and Epirus in northwestern Greece and with the island of Corfu.[14][15]
http://en.wikipedia.org/wiki/Antikythera_mechanism
