Cleaning. When an oil tanker or chemical tanker carries one cargo, it must usually be cleaned before the next cargo and also to reduce the "clingage" and residues on the parts of the ship's structure inside the cargo spaces.

Cartel. This is a price-fixing body formed of providers or suppliers of goods or services. A liner conference can be considered to be a cartel to fix the freight rates.

Ceiling.The ceiling consists of wooden planks laid on top of the double bottom tanks. The planks are laid longitudinally and prevent contact between the cargo and the double bottom.

Clear days. The "Charterparty Laytime Definitions" give a definition of "clear days" as:

Class surveyors’ assistance to vessel. If a vessel has sustained damage to such an extent that her seaworthiness may be affected, the master will contact the surveyor of the classification society, in order to ascertain what repairs have to be carried out for the maintenance of class.

Centre of gravity (G). The line of action of the weight (force) of a body acts vertically downwards through this point, named “G”. For a uniform block, G is at the centre. For a ship, the position of G depends on the various weights in the ship.

Collision and dock damage. Excess collision liability. Proportion of collision liability relating to wreck removal, dock damage or oil pollution caused by the other ship.

Colliery. A "colliery" is a coal mine and in voyage charters for the carriage of coal the laytime agreed may depend on the working hours of the mine, if the coal cargo has to be delivered to the vessel. The word is connected to expressions that affect laytime.

CFS (Container freight station). This is the name given to a container base where goods in quantities smaller than that which will fill an entire container (that is, “break bulk cargo” or a “less than container load” or “LCL”) are dispatched for stowing into a container (“stuffing” or “consolidating”). The CFS facilities may be offered by freight forwarders or even by carriers.

Consignment. Normally this means the sending or transmitting of goods from one place to another.

Concentrates. This is a material in small particle form which results from a processing of natural ore. The main hazard associated with concentrates is that moisture entrained in the particles may settle out and the surface reach a nearly fluid state which will affect the ship’s stability if the cargo shifts. Moreover, some concentrates, such as iron concentrates produced when iron is crushed dry, contain sulphur so that if concentrates become damp the sulphur reacts with the oxygen in the surrounding air to produce heat. Compartments containing concentrates should not be ventilated in order to reduce the oxygen content.

Complement. The entire crew of a vessel is called the “complement”. The complement can be subdivided into, for example, the officer complement, and the rating complement.

Charterparty. This is the document that contains the details of the charter or contract. While the shipowner and charterer are called the "parties to the charter", the word "party" in "charterparty" originates from the old Latin phrase for the contract to use a ship.

CY (Container yard). This is the container base from where the carriage will commence or where the ocean carriage ends. It is usually in the container port facility and is under the control of the ocean carrier. 

The CY can also be under the control of other carriers, for example, at a railway yard or at an airport.

Container leasing. Containers may be offered for carriage of goods by the carriers themselves or the carriers may not actually own the containers, rather leasing them from lessors. Other parties, such as shippers, may also wish to lease a container. Therefore the containers can be owned by the ocean carriers, the lessors and also other transport operators, such as railway companies, shippers C themselves and large freight forwarders.