Abstract: A time keeping device, including an integrated circuit memory containing tide table data, having the ability to provide custom port information using user supplied offsets. The device provides a tide prediction system to predict and display the times of high and low tides for numerous ports and adjacent areas spanning, for example, the East, West, and Gulf Coast regions of the continental U.S. The device allows the setting and display of the different Port/Substations supported by the tide prediction system, displays the current time, date, and day of the week in standard or military format (24 hour clock), and adjusts for Daylight Saving time. Displays are provided for the phases of the moon from New to Full and back to New Moon, indicating whether it is waxing or waning, and for the current water level height An audible alarm may be generated for the arrival of a new hour, arrival of the next tidal event, or the arrival of a time preset by the user, and the device may also function as a stop watch.