A chief mate (C/M) or chief officer, usually also synonymous with the first mate or first officer, is a licensed mariner and head of the deck department of a merchant ship. The chief mate is customarily a watchstander and is in charge of the ship's cargo and deck crew. The actual title used will vary by ship's employment, by type of ship, by nationality, and by trade: for instance, chief mate is not usually used in the Commonwealth, although chief officer and first mate are; on passenger ships, the first officer may be a separate position from that of the chief officer that is junior to the latter.
The chief mate answers to the captain for the safety and security of the ship. Responsibilities include the crew's welfare and training in areas such as safety, firefighting, search and rescue.
Senior onboard operations manager
The Chief Mate, who is the second in command of the vessel, is often equated, in corporate terms, to a senior manager for the operations on board, as the Mate is in charge of a number of departmental functions. In modern cargo vessels, the Mate holds appointments like Head of Deck Department, Head of Cargo/Stowage Operations, Head of Safety/Fire Fighting, Head of On-Board Security (Ship Security Officer), Head of Environment and Quality, and so forth.
Cargo officer
As cargo officer, a chief mate oversees the loading, stowage, securing and unloading of cargoes. Moreover, the chief mate is accountable for the care of cargo during the voyage. This includes a general responsibility for the ship's stability and special care for cargoes that are dangerous, hazardous or harmful.
Even under the best of conditions, a ship is balanced precariously upon the water and is subject to a number of forces, such as wind, swells, and storms, which could capsize it. The cargo officer uses tools like ballasting and load balancing to optimize the ship's performance for the expected type of environment.
Watchstanding
Traditionally, the chief mate stands a "4-8" watch: from 4 AM until 8 AM and 4 PM until 8 PM, in port and at sea, the chief mate is responsible to the captain for keeping the ship, crew, and cargo safe. On watch, the mate must enforce all applicable regulations, such as the International Convention for the Safety of Life at Sea and pollution regulations. In port, the watch focuses on duties such as cargo operations, fire and security watches, monitoring communications and the anchor or mooring lines.
IMO regulations require the officer be fluent in English. This is required for a number of reasons, such as ability to use nautical charts and nautical publications, to understand weather and safety messages, communicate with other ships and coast stations, and to be able to work with a multi-lingual crew.
Sea watch
At sea, the mate on watch has three fundamental duties: navigate the ship, safely avoid traffic, and respond to any emergencies that may arise. Mates generally stand watch with able seamen who act as helmsman and lookout. The helmsman executes turns and the lookout reports dangers such as approaching ships. These roles are often combined to a single helmsman/lookout and, under some circumstances, are eliminated. The ability to smartly handle a ship is key to safe watchstanding. A ship's draught, trim, speed and under-keel clearance all affect its turning radius and stopping distance. Other factors include the effects of wind and current, squat, shallow water and similar effects. Shiphandling is key when the need arises to rescue a man overboard, to anchor, or to moor the ship.
The officer must also be able to transmit and receive signals by Morse light and to use the International Code of Signals.
Navigation
Celestial, terrestrial, electronic, and coastal navigation techniques are used to fix a ship's position on a navigational chart. The officer directs the helmsman to keep to track, accounting for effects of winds, tides, currents and estimated speed. The officer uses supplemental information from nautical publications, such as Sailing Directions, tide tables, Notices to Mariners, and radio navigational warnings to keep the ship clear of danger in transit.
Safety demands the mate be able to quickly solve steering control problems and to calibrate the system for optimum performance. Since magnetic and gyrocompasses show the course to steer, the officer must be able to determine and correct for compass errors.
Weather's profound effect on ships requires the officer be able to interpret and apply meteorological information from all available sources. This requires expertise in weather systems, reporting procedures and recording systems.