Ballast Sea water that is pumped into the ship’s tanks to trim the ship, i.e. to ensure that she is not too high in the bow, or too high in the stern, or listing (leaning to one side) when putting to sea. Ballast is also put into a ship’s tanks to spread the weight (and therefore the stresses) along the length of the ship when loaded.

Bunkers Ships’ fuel. To bunker means to take on fuel in a port.

Lipuma is a Bunker Barge. That means she brings bunkers (fuel) to ships while they are in port working cargo. The white apparatus mounted in the midships section of Lipuma contains the pipe through which the bunkers are pumped aboard the ship. Photograph : African Marine Solutions (AMSOL)

Coaster A ship that trades along the coast of a country (e.g. from Durban to Cape Town, or between Australian ports) or the coast of a region (e.g. southern Africa). These ships are usually relatively small. The role of coasters has been reduced recently because of the widespread use of trucks to move cargoes between ports, while larger ships often carry containers between local ports during their coastal voyages. (e.g. a ship trading between South Africa and Europe may call at Durban and while loading cargo for Europe, she also loads cargo for Cape Town which is her next port of call en route to Europe.)

Geared ship A ship that has her own cranes.

Safmarine Chachai has three cranes on her foredeck and one on her afterdeck. Photograph: Ian Shiffman

Gearless ship A ship that does not have her own cranes.

MSC Eleni (below) does not have any cranes to lift cargo.   Photograph: Brian Ingpen

Knot The unit of measurement of the speed of a ship.  If a ship steams at 15 knots, she will cover 15 nautical miles in an hour or 27.78 kilometres in an hour. (1 knot = 1 nautical mile – see nautical mile below.)

Liner A ship that operates on a regular service (e.g. between certain ports in Europe and certain ports in South Africa) and has a published schedule. Most containerships operate on liner services.

Nautical Mile The unit of distance at sea. Its abbreviation is a capital M, e.g. 150M or 2400M. (1 nautical mile = 1.852 kilometres approximately)

Near-sea trader A ship that trades between countries across a relatively narrow sea or gulf (e.g. from Europe to the UK; from Europe to North Africa.)

Panamax A ship that can pass through the Panama Canal when she is fully loaded with cargo. The ship’s length, beam and draught are such that she can fit in the Panama Canal.

Post-Panamax A ship that is too large (too long, too wide and/or too deep) to pass through the Panama Canal fully loaded with cargo.

Stores Items that will be needed during a voyage – e.g. food, paint, engineroom requirements (other than fuel).

Trampship A ship that has no regular schedule. She calls at a port to load cargo, then goes to another port to discharge that cargo. She may return to the loading port if required to load another cargo, or she may go to another port to load a totally different cargo. (e.g. She loads grain in Argentina and goes to Durban to discharge the grain; then she takes steel from Durban to India where she discharges the steel. In India, she loads rice for Australia where she discharges the rice and loads coal for China.) Most bulk carriers operate as trampships.