ship’s bells

The ship’s bell is struck every half hour. A single stroke is struck a half hour after the beginning of each watch, at 12:30, 4:30, and 8:30 (both am and pm). An additional stroke is added at each tolling, every half hour, so that 8 bells is struck at the end of the watch. The interval between strikes is either one or two seconds, with two seconds between the pairs.

In the home clocks that strike ship’s bells usually follow that regular pattern. Ship’s bells as formerly struck at sea is a bit more complicated, because the day was divided into 7 watches, not 6 four-hour watches.

Time	Domestic clock	Nautical	Comment
12:30 pm	●	●
1:00 pm	●●	●●
1:30 pm	●● ●	●● ●
2:00 pm	●● ●●	●● ●●
2:30 pm	●● ●● ●	●● ●● ●
3:00 pm	●● ●● ●●	●● ●● ●●
3:30 pm	●● ●● ●● ●	●● ●● ●● ●
4:00 pm	●● ●● ●● ●●	●● ●● ●● ●●	The First Dog Watch starts at 4pm.
4:30 pm	●	●
5:00 pm	●●	●●
5:30 pm	●● ●	●● ●
6:00 pm	●● ●●	●● ●●
6:30 pm	●● ●● ●	●	The Second (or Last) Dog Watch begins at 6 pm and ends at 8pm, so this keeps to the pattern of 1 bell half an hour after the beginning of the watch.
7:00 pm	●● ●● ●●	●●
7:30 pm	●● ●● ●● ●	●● ●
8:00 pm	●● ●● ●● ●●	●● ●● ●● ●●
8:30 pm	●	●
9:00 pm	●●	●●
9:30 pm	●● ●	●● ●
10:00 pm	●● ●●	●● ●●
10:30 pm	●● ●● ●	●● ●● ●
11:00 pm	●● ●● ●●	●● ●● ●●
11:30 pm	●● ●● ●● ●	●● ●● ●● ●
12:00 midnight	●● ●● ●● ●●	●● ●● ●● ●●
12:30 am	●	●
1:00 am	●●	●●
1:30 am	●● ●	●● ●
2:00 am	●● ●●	●● ●●
2:30 am	●● ●● ●	●● ●● ●
3:00 am	●● ●● ●●	●● ●● ●●
3:30 am	●● ●● ●● ●	●● ●● ●● ●
4:00 am	●● ●● ●● ●●	●● ●● ●● ●●
4:30 am	●	●
5:00 am	●●	●●
5:30 am	●● ●	●● ●
6:00 am	●● ●●	●● ●●
6:30 am	●● ●● ●	●● ●● ●
7:00 am	●● ●● ●●	●● ●● ●●
7:30 am	●● ●● ●● ●	●● ●● ●● ●
8:00 am	●● ●● ●● ●●	●● ●● ●● ●●
8:30 am	●	●
9:00 am	●●	●●
9:30 am	●● ●	●● ●
10:00 am	●● ●●	●● ●●
10:30 am	●● ●● ●	●● ●● ●
11:00 am	●● ●● ●●	●● ●● ●●
11:30 am	●● ●● ●● ●	●● ●● ●● ●
12:00 noon	●● ●● ●● ●●	●● ●● ●● ●●

Ship’s bells are no longer rung on merchant ships, but the custom is maintained on passenger, training, and naval vessels.