Bells have been used on board ships for centuries. Because ships at sea sailed night and day, they
used a shift system to rotate crews. Three crews worked the ship normally, working four hours at a time.
This was called a "watch". Eight half hours, called "glasses" made up a watch. The helmsman's
duty was to turn the glass every half hour and sound the ship's bell a consecutive number of times.
At the sound of eight bells, the crew changed.
The quality of a bell is its weight and the manner of its casting, which creates its depth of sound.
A ship's bell's deep, rich sound increases with its size.