Watches and bells

Note: all times are based on the 24 hour clock, midnight to midnight. But, see Nautical time and civil date and GMT, Universal, Civil and Atomic. Also, this page describes the traditional naval and merchant watchkeeping system; while much of it is still completely valid, some variations have been introduced since 1964, e.g. engineering departments may be divided into three watches; this even goes as far as optionally the bell might not be struck during the middle watch, or possibly not sounded during fog to avoid potential confusion with fog signals.

While the origins are somewhat uncertain, but date back at least to the fifteenth century, a "watch" is traditionally a time period of four hours, during which half the crew (the "Port Watch" or the "Starbord Watch") is on duty (working, on deck, etc - "on watch") and the other half is resting ("off watch"). The nomenclature starts with the "first watch" (2000 until midnight), then the "middle watch" (midnight to 0400), the "morning watch" (0400 to 0800), the "forenoon watch" (0800 to noon) and the "afternoon watch" (noon to 1600).

The "evening watch" (1600 to 2000, or 4pm to 8pm) is further subdivided into "First Dog" and "Last Dog" watches ("Second Dog" in the US Navy); this gives an uneven number of watches each day, so that the crew alternates the "graveyard" watch (officially the "middle" watch which by starting at midnight is normally the least popular time to be on duty) and also serves for the evening meal.

Bells are used to mark the time during the watch, and are based on turning a half hour watch glass (a figure-of-eight or double-bubble hourglass holding a known quatity of sand); at the first turn on each watch the bell would be struck once, on the second turn twice, etc ..., with the sounds grouped by pairs. In the table below, each watch starts on the "eight bells" of the previous one:

First	Middle	Morning	Forenoon	Afternoon	Dogs
2030 - 1 bell	0030 - 1 bell	0430 - 1 bell	0830 - 1 bell	1230 - 1 bell	1630 - 1 bell
2100 - 2 bells (sounded as one pair)	0100 - 2 bells	0500 - 2 bells	0900 - 2 bells	1300 - 2 bells	1700 - 2 bells
2130 - 3 bells (one pair and a single)	0130 - 3 bells	0530 - 3 bells	0930 - 3 bells	1330 - 3 bells	1730 - 3 bells
2200 - 4 bells (two pairs)	0200 - 4 bells	0600 - 4 bells	1000 - 4 bells	1400 - 4 bells	1800 - 4 bells
2230 - 5 bells (two pairs and a single)	0230 - 5 bells	0630 - 5 bells	1030 - 5 bells	1430 - 5 bells	1830 - 1 bell*
2300 - 6 bells (three pairs)	0300 - 6 bells	0700 - 6 bells	1100 - 6 bells	1500 - 6 bells	1900 - 2 bells*
2330 - 7 bells (three pairs and a single)	0330 - 7 bells	0730 - 7 bells	1130 - 7 bells	1530 - 7 bells	1930 - 3 bells*
2400 - 8 bells (four pairs)	0400 - 8 bells	0800 - 8 bells	1200 - 8 bells	1600 - 8 bells	2000 - 8 bells

Note: The end of the watch is considered as 8 bells, hence the saying "Eight bells and all is well." This applies to the Last (Second) Dog watch which strikes 1, 2 and 3 bells (* in the table) during the watch. See various editions of the Admiralty Manual of Seamanship.