A ship-log records the distance travelled through the water. With the time in hours between the observations, it gives the ship’s speed in knots.

The Trident is a large version and predecessor of the Cherub log, disigned for high speeds of 18 knots and upwards. The clock has to be fixed on the rail at the stern of a ship, the taffrail. The recorder would have been connected with a short line to the spinner and the spinner with a line of about 65 fathoms to the rotator at the end of the line. Drum and tube shape are made of brass and mounted on a gimbal foot. Serial number X2672. Makers brass plate on the body. Three dials. For use with the Cherub rotator. The original rotator with rope is missing one blade. If desired another, complete rotator can be delivered but without rope.
Thomas F. Walker (1837–1921) patented a log in 1878, the Walkers patent taffrail ship-log. It was one of the first logs in which the recorder was placed on board the ship rather than being part of the rotator. The production of the Trident commenced in 1905 and ceased around 1938. Details and serial number suggests a manufacture date around 1920.

Catalog: NM.4-28
Date: ca. 1920
LD clock: 26×13 cm (10.2×5.1 in)
LD rotor: 40×16 cm (16×6 in)
Signed: Walker’s “TRIDENT”
Origin: England
Condition: in good condition, one rotorblade missing