Demurrage in shipping is the charge a shipowner collects when a vessel spends longer at berth than the laytime allowed under the charter party. It compensates the owner for lost earning time once loading or discharge runs past the agreed schedule.
How Laytime and Demurrage Rates Work
Laytime is the number of days, or hours, a charter party allocates for loading and discharging cargo. Owners and charterers negotiate that figure before the voyage and write it into the charter party alongside a daily demurrage rate.
Once the vessel exceeds laytime, demurrage accrues automatically, hour by hour, until cargo operations finish and the vessel is ready to sail. Owners typically set demurrage rates as fixed lump sums per day rather than calculating them from actual costs.
That’s why owners and charterers negotiate rates carefully at the fixture stage, often benchmarking the daily rate against current market hire so it’s neither too low to matter nor too high to be workable if delays occur.
What Triggers Demurrage in Practice
Delays that trigger demurrage are rarely dramatic. Slow cargo handling, equipment breakdowns at the terminal, customs holds, or a queue for port agency in Curaçao support can each eat into laytime without anyone doing anything wrong.
Weather stoppages sometimes count against laytime and sometimes don’t, depending on whether the charter party treats them as excepted periods. Because these clauses vary by contract, what a port agent does day to day often includes tracking laytime consumption in real time so disputes don’t surface only after the vessel has sailed.
Notices of readiness add another layer of complexity. Laytime typically doesn’t start counting the moment a vessel arrives; it starts once the master tenders a valid notice of readiness and the charterer accepts it. The charter party spells out the exact timing rules for that step rather than leaving them assumed. Charterers can challenge a notice tendered outside berth hours, or before the vessel is genuinely ready to load.
Demurrage vs Detention
Demurrage and detention get confused often, but they apply to different situations. Demurrage relates to a chartered vessel exceeding laytime under a voyage charter.
Detention, by contrast, usually applies to containers held by a shipper or consignee beyond the free time a carrier allows, outside the port terminal rather than at berth. Both penalize the same underlying problem, slow turnaround, but demurrage sits between owner and charterer while detention sits between carrier and cargo interest.
BIMCO’s standard laytime definitions give owners and charterers a shared vocabulary for these calculations, detailed in its laytime and demurrage guidance. The International Chamber of Shipping also publishes broader guidance on charter party risk allocation, available through its shipping industry guidance library.
Managing Demurrage Risk
Predicting a Curaçao port call’s total duration matters as much as the laytime clause itself, since how long a Curaçao port call takes depends on berth availability as much as cargo operations.
Most demurrage disputes are avoidable with better information flow earlier in the process. A charterer who receives daily updates on cargo handling progress can flag a slowdown while there’s still time to speed up the remaining operation.
Some charter parties also include a despatch clause, paying the charterer a reward for finishing faster than laytime allows. This gives terminals and stevedores a direct incentive to keep operations moving rather than treating the allotted time as a target to use in full.
Demurrage is ultimately a scheduling risk turned into a cost. Clear laytime terms, accurate ETAs, and a port agent who tracks time consumption from arrival to departure are the practical tools for keeping it to a minimum, which is the role SeaHarbor plays for vessels calling Curaçao.
What Owners Should Confirm Before Fixing
Before agreeing to a charter, owners should confirm the exact laytime calculation method the fixture uses, since some charter parties count laytime in running hours and others exclude weekends or holidays entirely. Confirming this detail up front avoids a dispute later over how many hours actually counted.
Charterers benefit from the same clarity. Knowing exactly when the laytime clock starts and stops removes one of the most common sources of disagreement at settlement.