Seatrack’s Start Line function is designed to give the tactician second-to-second information on the time needed to arrive at relevant points on the start line. This is calculated by reference to the yacht's start line polars, which are automatically loaded at the warning gun and replaced by the race polars at the start gun. Calculations take into account the time taken to turn, deceleration during the turn and acceleration rates.

The principal Start Line information can be sent to a PDA so that the data is available on deck. After the starting signal, the PDA automatically reverts to displaying Virtual Instrument data.