A more thorough explanation:

Demurrage is a term used in maritime law to refer to the liquidated damages that a charterer owes to a shipowner for failing to load or unload cargo within the agreed time. There are two types of demurrage:

This is demurrage that is paid by a charterer if the time to load or unload the vessel at port takes longer than what was agreed upon in the charterer's contract with the shipowner. For example, if a charterer agrees to unload a cargo ship within three days but takes five days to do so, they will have to pay contract demurrage to the shipowner.

This is demurrage that is not provided for in the contract but is ordered by a court. For example, if a charterer fails to unload a cargo ship within the agreed time and the shipowner takes them to court, the court may order the charterer to pay non-contract demurrage as damages for detention.

In addition to the above, demurrage can also refer to a charge that is due for the late return of ocean containers or other equipment.

Overall, demurrage is a way to compensate shipowners for the loss of time and money caused by a charterer's failure to load or unload cargo within the agreed time.