Watchstanding, or watchkeeping, in nautical terms concerns the division of qualified personnel to operate a ship

Ship

Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

 continuously around the clock. On a typical sea going vessel, be it naval or merchant, personnel keep watch on the bridge and over the running machinery. The generic bridge watchstanders are a lookout and an officer or mate who is responsible for the safe navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

 of the ship. Safe navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

 means keeping the vessel on course and away from dangers as well as collision avoidance from other shipping. An engineering specialist ensures that running machinery continues to operate within tolerances and depending on the vessel, this can also be accomplished from the bridge. A secondary function of watchkeeping is the ability to respond to emergencies, be it on own ship or involving other ships.

Types of watches

A wide variety of types of watches have developed due to need aboard merchant and naval vessels. This section gives some examples.

Engineering watches

• Naval
  • Engineering Officer of the Watch
  • Damage Control Watch Officer
  • Boiler watches
  • Electrical, intercom, and auxiliary watches
  • Main engine and auxiliary watches

Navigational watches

• Merchant
  • Mate on watch
  • Helmsman
  • Lookout
• Naval
  • Officer of the Deck
  • Junior Officer of the Deck
  • Junior Officer of the Watch
  • Conning Officer
  • Quartermaster of the Watch
  • Boatswain's Mate of the Watch
  • Helmsman
  • Lookout
  • Low-visibility detail

Security watches

• Merchant
  • Gangway watch
  • Special piracy-related watches
• Naval
  • Petty Officer of the Watch
  • Officer of the Deck (In-port)
  • Roving patrol
  • Sounding and security
  • Pier sentry

Communications watches

• Merchant
  • Radio watch
• Naval
  • Radio watches
  • Message center
  • Signal bridge watches

Other types of watches

• Merchant
  • Cargo watch
  • Anchor watch
• Naval
  • Anchor watch
  • In-port Boat Officer
  • Department Duty Officer
  • Communications Watch Officer
  • Tactical Action Officer
  • Command Duty Officer
  • Combat Information Center Watches
    • Combat Information Center Watch Officer
    • Other CIC Watches

Duration

Watch durations will vary between vessels due to a number of reasons and restrictions. The traditional three-watch system is from the days of sail, where the ships company was divided into three and the day divided into six watches of four-hours duration, such that an individual would keep two four-hour watches each day separated by an eight-hour time for sleep or recreation. Examples of other systems include 4 by 6-hour and 7's and 5's when a warship has half its ships company on watch at a time.

Traditional watch system

A 2-Section Dogged Watch

Name	Time	Day 1	Day 2	Day 3
First watch	2000-0000	Team 1	Team 2	Team 1
Middle watch	0000-0400	Team 2	Team 1	Team 2
Morning watch	0400-0800	Team 1	Team 2	Team 1
Forenoon watch	0800-1200	Team 2	Team 1	Team 2
Afternoon watch	1200-1600	Team 1	Team 2	Team 1
First dog watch Dog watch Dog watch, in marine or naval terminology, is a watch, a period of work duty or a work shift, between 1600 and 2000 . This period is split into two, with the first dog watch from 1600 to 1800 and the second dog watch from 1800 to 2000...	1600-1800	Team 2	Team 1	Team 2
Last dog watch Dog watch Dog watch, in marine or naval terminology, is a watch, a period of work duty or a work shift, between 1600 and 2000 . This period is split into two, with the first dog watch from 1600 to 1800 and the second dog watch from 1800 to 2000...	1800-2000	Team 1	Team 2	Team 1

The watches kept on sailing ships—the square-rigged barques or windjammers of the late 19th century and in the British Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

—consisted of 5 four-hour periods and 2 two-hour periods. Those members of the crew whose work must be done at all times of the day were assigned to one of two divisions: the Starboard or the Port division. These two groups of personnel alternated in working the following watches:

This pattern allowed the two watches, known as the 'port' and 'starboard' watches, to alternate from day to day, so that the port watch had the night watch one night and the starboard watch had it the next night.

A similar system can also be used with a crew divided into three, giving each sailor more time off-duty. Names for the three watches—instead of Port and Starboard—vary between ships; "Foremast", "Mainmast" and "Mizzen" and "Red", "White" and "Blue" are common.

Watches and ship's bells

Ship's bells are a system to indicate the hour

Time

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

 by means of bell

Bell (instrument)

A bell is a simple sound-making device. The bell is a percussion instrument and an idiophone. Its form is usually a hollow, cup-shaped object, which resonates upon being struck...

s, used aboard a ship

Ship

Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

 to regulate the sailors' duty watches.

Unlike civil clock

Clock

A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...

bells, the strikes of the bell do not accord to the number of the hour. Instead, there are eight bells, one for each half-hour of a four-hour watch. Bells would be struck every half-hour, and in a pattern of pairs for easier counting, with any odd bells at the end of the sequence.

The traditional system is:

Number of bells	Middle watch	Morning watch	Forenoon watch	Afternoon watch	First dog watch	Last dog watch	First watch
One bell	0:30	4:30	8:30	12:30	16:30	18:30	20:30
Two bells	1:00	5:00	9:00	13:00	17:00	19:00	21:00
Three bells	1:30	5:30	9:30	13:30	17:30	19:30	21:30
Four bells	2:00	6:00	10:00	14:00	18:00		22:00
Five bells	2:30	6:30	10:30	14:30			22:30
Six bells	3:00	7:00	11:00	15:00			23:00
Seven bells	3:30	7:30	11:30	15:30			23:30
Eight bells	4:00	8:00	12:00	16:00		20:00	0:00