What is Detention?

Hint - it's not just the thing your teachers used to give you for not doing homework.

After last week's post on demurrage I received a few messages asking about detention. They often go hand in hand but they are not the same thing. In container shipping, demurrage refers to the time a container spends inside the terminal beyond the agreed free time.

Detention refers to the time the carrier's container spends outside the terminal, port, or depot beyond the agreed free time.

For example, if five days' detention-free time has been granted, this means once a company has picked up the containers from the port, it has five days to unpack the cargo and return the empty container to the nominated terminal, port, or depot. If it fails to do so, detention charges will be applied to the container(s).

On small shipments of a few containers this is usually a relatively simple task. However, on larger shipments where companies are managing limited free days for both demurrage and detention, it requires careful coordination between logistics providers, warehouses, and sometimes the end users themselves to ensure charges are avoided.

If the containers are not returned on time, the shipping line cannot use that equipment for another customer or another voyage.

Like demurrage, the number of detention-free days is usually negotiated at the point of booking the container shipment. Depending on the size and complexity of the shipment, companies may be willing to pay slightly higher freight rates in order to secure more free days demurrage and detention (often called 'D&D').

For containers the distinction is simple:
Demurrage = the container is still inside the port or terminal.

Detention = the container has left the port or terminal but has not yet been returned.