Sandglass
Description
One part of a sandglass timer. Conical shape with a small opening at the top.
A sandglass was a method of keeping time at sea; whether that time keeping was used to manage how long a ship sailed a particular course or for regulating the time sailors spent on watch. During sea passages, the naval watch system divided 24 hours of the day into six four-hour watches with half the ships company on watch and the other half off duty. Each four-hour watch was marked every 30 minutes by ringing the ships quarterdeck bell. After the first 30 minutes, one bell would be sounded; thirty minutes later two bells, and so on up to eight bells at the end of the four-hour watch. The timing of these shifts of course was measured through the use of sandglasses.
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