Custom of the port (COP). The word "custom" has a purely legal meaning and also a meaning connected with chartering practice and laytime. The meaning for lawyers is that it is a rule of conduct established by long usage over many years.
Clean bill of lading. The carrier is bound to deliver the goods in the same order and condition as when he received them into his charge. When the goods are received, the bill of lading is issued, on demand of the shipper, and this should state the description of the goods as received, including the apparent order and condition.
Cargo capacity. This is the quantity of cargo the ship can carry or the volume of the space the ship has for cargo. It is found in the charterparty clause describing the ship and is part of the shipowner's warranties about the ship. If the ship does not meet the description given by the owner, he could become liable for a "breach of warranty" and have to pay compensation or damages or perhaps even a "breach of condition", allowing the charterers to cancel ("repudiate") the charter.
Cesser clause. It is customary to insert a special clause in voyage charterparties, where the charterers' liability ceases as soon as the cargo is shipped and the advance of freight, deadfreight and demurrage in loading (if any) are paid, the owners have a lien on the cargo for freight, deadfreight, demurrage and general average contributions.
Charterer's agents. In charterparties covering a fixture on an f.i.o. (free in and out) basis, which implies that the loading and discharging expenses are for the charterer's account, charterers often insist upon the right to appoint their agents to attend to the ship's business at "both ends" (i.e., loading and discharging ports) at a fee.
Charterers' bills of lading. The relationship between charterparties and bills of lading can range from a simple one, where the bill of lading from a shipowner to a charterer/shipper has the status only of a receipt for cargo, to a complex one, where, for example, a charterer issues a bill of lading on his own form but includes a "demise clause" which states that the person issuing the bill of lading is not the owner nor demise-charterer of the vessel and the holder of the bill of lading is then left with the uncertainty of whom to sue for loss, damage or delay of the cargo carried under the bill of lading.
CHOPT (Charterer's option). If the charterers has an option to nominate any detail in a charter, for example, the "tolerance" percentage of the quantity of cargo to be loaded, this abbreviation is used in fixture telexes and other communications. For example, it may be that the cargo to be loaded is "50,000 metric tons 10pct. CHOPT". The charterers are allowed to require between 45,000 and 55,000 tonnes of cargo to be loaded, paying freight accordingly.