Thursday, November 27, 2014

Walker's "Cherub" III Taffrail Ship-Log

For sale at the Art of the Sea gallery in South Thomaston Me.

More info:

(The Walker Cherub III Log) was developed in 1879, 13 years after the Harpoon log, by Thomas Ferdinand Walker for larger size ships. It is immense in size compared to other logs, and is arguably the most useful and long serving log offered.

It was made by Thomas Walker & Son, Ltd of Birmingham, England whose name is synonymous with patent logs. It features a self contained instrument head with a distance measuring calculator which was mounted on the vessel's taffrail. The instrument section has a white porcelain face, and three analog counters with black Arabic numbers for distance run. A very large spinner or fish is trailed in the water behind the ship and its rotation is transmitted to the counter by means of a line.

From blog has a humorous take on the instrument, worth reading)

This instrument is a recorder for determining distance travelled and thus ship’s speed. It is made of brass with a ceramic dial, with the main scale marked from 0 to 100 miles and two inset dials marked from 0 to 1000 miles and 0 to 1 mile. It has a fixing plate, on which it can turn, with which it would have been attached to a suitable part of the ship, typically the taffrail, the rail at the stern of a ship. As a result, this type of log was often called a taffrail log. The recorder would have been connected to a rotor that was towed behind the ship. The revolutions of the rotor registered on the indicator, thus measuring the distance travelled. For this model, 900 revolutions of the rotor registered as 1 nautical mile.

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