Ship's Log | Nantucket Antiques
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Antiques Snippets – Ships Logs

Commonly asked questions and misunderstandings about antiques… and the odd or end fascinating bit!

Ship's Log | Nantucket Antiques What are those little brass torpedoes attached to long ropes? They are ship’s logs and were used by sailors to measure their speed under weigh at sea.

Ever since sailors first ventured out of sight of land, the simplest dead-reckoning navigation required skippers to judge how fast they were moving. The original simple solution was to toss an actual log overboard, attached to a line paid out with a knot tied at regular intervals: the sailor counted how many knots passed his hand over a measured time period. The resulting measurement came to be called a knot, or nautical mile per hour, later defined as the speed required to travel approximately one minute of geographical latitude in one hour.

By the 18th century, sailors began using Taffrail or Patent Logs, a sort of sea-going odometer with a gauge mounted on the Taffrail (on the stern) recorded speed based on distance traveled as measured by a rotating vane towed behind the vessel.

What about the ship’s Logbook? By now you’ve probably guessed it started as a book used to record the log readings, but then evolved to include all weather and sailing observations, as well as mention of any noteworthy events during the voyage.

Antiques Snippets are provided by Jack Fritsch, proprietor of the Antiques Depot at 2 S. Beach Street (across from the Nantucket Yacht Club) .

Articles by Date from 2012