Ekman current meter

The Ekman current meter is a mechanical flowmeter invented by Vagn Walfrid Ekman, a Swedish oceanographer, in 1903. It comprises a propeller with a mechanism to record the number of revolutions, a compass and a recorder with which to record the direction, and a vane that orients the instrument so the propeller faces the current. It is mounted on a free-swinging vertical axis suspended from a wire and has a weight attached below.