Ship Crew Roles & Navigation Fundamentals
Ship Crew Roles and Responsibilities
Officer Roles
Chief Mate
The Chief Mate’s primary responsibilities are:
- Creating the stowage plan.
- Supervising the loading and discharging of cargo.
- Supervising general ship maintenance.
Second Officer
The Second Officer (or Second Mate) of a merchant vessel is responsible for the navigational equipment and is traditionally the ship’s navigational officer. The Second Officer is the third-in-command, after the Master and Chief Mate, and typically stands the twelve o’clock watches (12:00-16:00 and 00:00-04:00).
Third Officer
The Third Officer (or Third Mate) acts as a safety officer for the ship and crew, responsible for all safety equipment on board. The Third Mate is the fourth-in-command, after the Master, Chief Mate, and Second Mate, and stands the eight o’clock watches (08:00-12:00 and 20:00-24:00).
Deck Cadet
A Deck Cadet (or apprentice officer) is an officer in training, reporting to the Chief Officer. Cadets receive training in:
- Firefighting
- First aid and survival techniques
- Navigation
- Ship handling
- Cargo handling
- Maritime law
Their role as a trainee is to observe and learn while assisting where possible, primarily the Chief Officer. As they do not hold a Certificate of Competency, cadets cannot stand a watch alone but will likely assist a qualified officer, often the Chief Officer, with their watch.
Deck Ratings
Boatswain (Bosun)
A Boatswain, or Bosun, is the most senior rating and the head of the deck ratings. The Boatswain is responsible for all deck work, including the maintenance and repair of deck equipment. The Bosun generally carries out tasks instructed by the Chief Mate, directing the Able Seamen and Ordinary Seamen, and typically does not stand a navigational watch.
Able Seaman (AB)
An Able Seaman (AB) is a member of the deck department who works under the Bosun. Tasks include maintenance of deck rigging and machinery (loading gear, cranes, ramps, doors, lifts, hoses) and mooring equipment (windlass, anchors, cables, wires, etc.). The AB also stands a navigational watch, generally as a lookout or helmsman.
Ordinary Seaman (OS)
An Ordinary Seaman (OS) is the lowest-ranking personnel in the deck department. An OS performs various duties concerning the operation and upkeep of deck department areas and equipment, generally helping with work the Able Seamen are doing. Other tasks include standing lookout and general cleaning duties.
Maritime Navigation Principles
Watch Schedule
Standard sea watches are typically divided as follows:
- First Watch: 20:00 – 24:00
- Middle Watch: 00:00 – 04:00
- Morning Watch: 04:00 – 08:00
- Forenoon Watch: 08:00 – 12:00
- Afternoon Watch: 12:00 – 16:00
- Evening Watch (Dog Watches may split this): 16:00 – 20:00
Key Terminology
Heading: The direction in which the vessel is pointing. It is the angle between the fore-and-aft line of the vessel and true north.
Course: The intended sailing direction of the vessel.
Track: Consists of one or more course lines along which the navigator intends to proceed for a safe passage.
Great Circle Course: Forms the shortest connection between two places on the Earth.
Rhumb Line (Loxodrome): Forms a line where the angles made by the course line and the meridians are equal.
Composite Sailing: Combines the advantages of the great circle and the rhumb line; it offers the shortest possible route while allowing the vessel to keep constant true directions for segments.
Course Made Good: The course that the ship follows after allowing for the effects caused by wind.
Course Over Ground: The actual path of the vessel over the seabed, resulting from correcting the Course Made Good for the effect of current.
Position Fixing Methods
Cross Bearings: Form an intersection of two bearing lines taken from two conspicuous objects. The intersection provides the vessel’s position. If a third bearing line is taken as a check, the three lines ideally intersect at a point, but often form a small triangle, called a cocked hat.
Running Fix: Made when only one conspicuous object is available. It is done by taking two bearings of the same conspicuous object at an interval, accounting for the vessel’s movement between bearings.
Dead Reckoning: Determining one’s position by calculation, using a previously determined position (fix) and advancing it based on known or estimated speeds, directions, and time elapsed.
Navigation Systems
Astronomical Navigation: Determining position using celestial bodies (sun, moon, stars, planets).
Satellite Navigation: Determining position using signals from artificial satellites (e.g., GPS, GLONASS, Galileo).