A separate freight charge, in addition to ordinary shipping costs, which is imposed according to the terms of a carriage contract upon the person responsible for unreasonable delays in loading or unloading cargo. In maritime law, demurrage is the amount identified in a charter contract as damages payable to a shipowner as compensation for the detention of a ship beyond the time specified by a charter party for loading and unloading or for sailing.
Demurrage is intended to serve the public interest by facilitating the flow of commerce through the prompt loading and unloading of cargo. In general, the person liable for demurrage is the one who assumed the duty to unload or load the cargo but failed to fulfill it. A consignee who agrees to unload a shipment but unreasonably delays in doing so is liable for the charge.
Payment of demurrage is excused only if the delay was unavoidable, such as a delay caused by a natural disaster or the fault of the carrier. Reciprocal demurrage may be imposed upon a carrier who unreasonably delays in providing transportation to customers. The practical effect of reciprocal demurrage is a reduction in the customer's shipping charges unless the contractual amount exceeds that figure. If a person against whom demurrage is imposed fails to pay, the carrier might have a right to keep the goods until payment is made. This is known as demurrage lien, enforceable only if authorized by statute, contract, or custom.