Stroomschuifkaart Noordzee

A flow slide card consists of a sleeve with holes. The cover shows a certain sea area in map form on a small scale on both sides. Moving a slider in the cover changes the power information visible in the holes. The slider must be set to the number of hours before or after high water (HW) relative to the base port shown on the map.

The flow information is given by means of arrows and with the current in tenths of a mile.

A flow slider card works quickly and conveniently. A flow slide card can be used for many years at a time; after all, the pattern of the tidal currents in a certain area will not change quickly.