A minicomputer application to graphically display tidal current drift

Calculations on a minicomputer have been carried out to account for the drift of an object due to tidal currents for up to three tidal cycles. An algorithm using the National Ocean Survey tidal current tables and tidal current charts of Long Island sound and Block Island sound as data sources accounts for the changes in current velocity over the duration of the tidal cycles. This algorithm allows for entry of the last known position and time of an object and yields both a graphic and tabular display of subsequent times and positions of the object. The resulting drift position can then be used on the same drift position from other geographic positions or can be used to update the most probable position in search-and-rescue case planning