Why detention costs are decided before the vessel arrives

Every shipper who has paid a detention invoice they did not expect asks the same question afterwards: at what point did this become unavoidable? The answer is almost always the same, and it is earlier than people think. By the time a container is discharged, most of the exposure is already fixed.

Where the clock actually starts

The contract specifies which event starts the clock and how free time is calculated. Detention arrangements may be separate from or combined with demurrage, and the applicable bill of lading, carrier terms and tariff govern the charge. The example below counts calendar days using the published calculator schedule. The tariff bands escalate, so the cost is not linear — at Jebel Ali the first chargeable period runs at AED 147 a day for a 20ft unit, and by the fourth week the same box is running at AED 520. An overrun can become substantially more expensive as the applicable daily bands increase.

The controllable decisions are all made before the vessel berths. After discharge you are managing consequences, not causes.

The four decisions that set the bill

1. Documentation reviewed in advance. A bill of lading that has not been surrendered, a missing certificate, an inconsistent commodity description — each of these stops the box at the gate while the clock runs.
2. The slot booked against the discharge date. If the facility is booked for the week after the vessel arrives, the container waits.
3. The replacement equipment positioned. On a cross-stuffing job, the outbound container has to be on the ground before the inbound one is opened.
4. Transport arranged for the day of release. Not the day after. A single day of drift at the front of the operation is a day at the back of it too.

What good planning is worth

Take an illustrative case: three 40ft containers held for five, 12 or 19 calendar days. Using the calculator’s published five free days and 40ft bands, the following estimates exclude VAT and other charges. Actual free time and rates depend on the carrier and contract.

For 12 days, the estimate is 3 × [(4 × AED 257) + (3 × AED 420)] = AED 6,864. For 19 days, it is 3 × [(4 × AED 257) + (7 × AED 420) + (3 × AED 720)] = AED 18,384. These are examples using the displayed schedule, not a quotation.

Model it before you commit

Our Jebel Ali detention calculator shows the bands used in this example. The BND calculator provides a separate schedule, and the Jebel Ali port storage tariff covers terminal storage. Run the numbers against your own free time and agreed rates before a booking is committed.

If you would like us to look at a specific movement, send us the details and we will come back with a working view of the exposure.