If you are involved in voyage chartering, you have likely asked: what is a demurrage claim? In short, it is a claim for liquidated damages when a vessel exceeds its agreed laytime. For UK-based commodity traders, shipowners, charterers, and logistics professionals, understanding the mechanics of demurrage is not optional. A single port call on a Capesize vessel can generate a six-figure claim in under a week. This guide sets out the legal foundation of demurrage under English law, explains how laytime is calculated, distinguishes demurrage from detention, and provides practical strategies for managing or defending a claim in 2026. By the end, you will understand both the theory and the steps required to protect your position, whether you are pursuing or facing a demurrage claim.
A demurrage claim arises when a charterer or cargo receiver detains a vessel beyond the agreed laytime period for loading or discharging cargo. The obligation to pay demurrage stems from the voyage charter party, the contract governing the use of the vessel for a specific voyage. When the free time expires and the vessel remains at the charterer's disposal, the clock continues running, and the daily demurrage rate begins to accrue.
Under English law, demurrage is classified as liquidated damages for breach of contract, not a penalty. This distinction is critical. It means the shipowner's recovery is limited to the agreed daily rate, regardless of whether the actual loss suffered is higher or lower. English courts will not re-open a demurrage rate simply because market conditions have shifted. The Baltic Code (2020) reinforces this, defining demurrage as "an agreed amount payable to the owner in respect of delay to the vessel beyond the laytime, for which the owner is not responsible."
This contrasts sharply with French law, where demurrage is treated as a contractual penalty, or "supplément du fret," under Article R5423-23 of the Code of Transports. French courts have greater latitude to adjust the sum if it appears manifestly excessive. For UK readers dealing with European counterparties, this jurisdictional divergence can influence choice-of-law and dispute resolution clauses at the fixture stage.
A key principle for UK readers is the maxim "once on demurrage, always on demurrage." English courts strictly enforce this rule, meaning that exceptions to laytime, such as adverse weather or port congestion, do not automatically pause demurrage once it has begun. Only a clause clearly worded to apply after the vessel is on demurrage will have that effect.
To understand a demurrage claim, you must first understand laytime. Laytime is the period of free time allowed to the charterer for completing cargo operations. It can be expressed in several ways: as a fixed number of days or hours, by rate (where the cargo quantity is divided by an agreed loading or discharging rate), or as reversible, where unused laytime at the load port can be carried over to the discharge port. Non-reversible laytime keeps the calculations separate.
The laytime clock starts ticking upon the valid tender of the Notice of Readiness (NOR). The NOR is a formal declaration from the master that the vessel has arrived at the agreed destination and is ready in all respects to load or discharge cargo. A defective NOR, for instance, one tendered before the vessel is truly ready or to the wrong party, can invalidate the entire demurrage claim. Shipowners must ensure the NOR is tendered strictly in accordance with the charter party terms.
Several standard clauses modify when laytime commences, particularly where the vessel cannot immediately reach a berth. WIBON (Whether In Berth Or Not) allows the NOR to be tendered even if no berth is available, provided the vessel is within the port. WIPON (Whether In Port Or Not) goes further, permitting NOR tender when the vessel is at the usual waiting anchorage, even if outside formal port limits. WIBOLCON (Whether In Berth Or Not, Whether Customs Cleared Or Not) and NAABSA (Not Always Afloat But Safely Aground) address specific operational scenarios.
Excluded periods, such as weather interruptions, weekends, holidays, or equipment breakdowns, are only deductible if the charter party explicitly states they are exceptions to laytime. The drafting matters enormously. A practical example illustrates the stakes: a Capesize bulk carrier with a demurrage rate of $25,000 per day detained for five days generates a $125,000 claim from a single port call. For a vessel fixed on a consecutive voyage charter, the exposure multiplies rapidly.
The difference between exceptions and interruptions is often decisive in arbitration. Exceptions to laytime require the charterer to prove a causal connection between the excepted event and the delay. If a storm hits but the vessel would not have worked cargo anyway due to congestion, the exception may fail. Interruptions to laytime, by contrast, only require proof that the excluded state of affairs existed, regardless of causation. This nuance, drawn from John Schofield's authoritative analysis, means that charterers negotiating "interruptions" language gain a significant tactical advantage. Shipowners, conversely, should resist such wording.
This maxim is a cornerstone of English demurrage law, and its practical consequences are severe for charterers. Once the vessel is officially on demurrage, laytime exceptions, such as strikes, bad weather, or port congestion, do not automatically pause the running of demurrage. The financial clock keeps ticking.
The only way to stop demurrage accruing is via a clause that is clearly worded to apply even after the vessel is on demurrage. English courts interpret such clauses narrowly. The cases of the MSC Amsterdam and The Union Amsterdam illustrate how judges will not imply demurrage exceptions where the charter party is silent. The practical takeaway is clear: charterers should negotiate specific "demurrage exception" clauses at the fixture stage. Relying on general laytime exceptions to protect you once demurrage has commenced is a costly mistake.
Demurrage and detention are distinct legal concepts, and confusing them can lead to under-recovery or a failed claim. Demurrage applies only during the period after a valid NOR has been tendered and before cargo operations are complete. It is a fixed, agreed daily rate, recoverable as liquidated damages.
Detention, by contrast, applies outside the laytime window. It arises before laytime commences, for example, where the vessel waits for a berth due to the charterer's failure to have cargo ready, or after cargo operations finish, such as when the charterer delays providing bills of lading. Detention is a claim for unliquidated damages, meaning the shipowner must prove actual loss. The sum recovered may be higher than the demurrage rate, reflecting the true market loss, but the burden of proof is heavier.
Key case law distinguishes the two. In The Boral Gas, the court examined delay after discharge. The Mass Glory and The Timna further clarified the boundaries. For shipowners, a detention claim can yield greater compensation, but it requires robust evidence of the vessel's lost earning capacity. For charterers, understanding this distinction is essential because a poorly drafted claim may be defeated on the basis that the wrong remedy has been pursued.
Primary liability for demurrage sits with the charterer under the voyage charter party. However, the net of liability can spread wider. Bill of lading holders can be held liable for demurrage if the charter party terms are effectively incorporated into the bill of lading. The case of Porteus v. Watney established that a receiver who takes delivery of cargo under a bill of lading incorporating the charter party may be personally liable for discharge port demurrage, even if they were not the original charterer.
The sales contract terms also shape liability. Under a CIF sale, the seller, who is typically the charterer, bears responsibility for loading demurrage. Under an FOB sale, the buyer may be liable for discharge demurrage. The practical risk for a UK importer taking delivery under a bill of lading is significant: you could face a demurrage claim from a shipowner you never contracted with directly. Reviewing the incorporation language in bills of lading is not a mere formality; it is a risk management necessity.
Calculating a demurrage claim requires precision. Errors in time zones, NOR timing, or the interpretation of excluded periods can invalidate or substantially reduce a claim. Follow these steps.
Step one: determine the allowed laytime from the charter party. This may be expressed in days, hours, or as a rate-based calculation. Step two: record the exact time of valid NOR tender and the precise moment laytime commenced, accounting for any notice periods. Step three: calculate the actual time used for cargo operations, deducting only those periods that the charter party clearly excludes. Step four: subtract the allowed laytime from the actual time used. The remainder is the demurrage period. Step five: multiply the demurrage period by the daily demurrage rate, pro-rating for any fraction of a day.
Consider this example. A vessel has an allowed laytime of 72 hours, or three days. Actual time used for cargo operations is 120 hours, or five days. The demurrage period is 48 hours, or two days. At a daily rate of $25,000, the claim value is $50,000. Common pitfalls include failing to account for time zone differences between the port and the charter party's governing time standard, accepting an invalid NOR, and misinterpreting "weather working days" clauses. A weather working day of 24 hours is not the same as a calendar day, and the distinction can shift the demurrage calculation by thousands of dollars.
When a demurrage claim arrives, charterers have several lines of defence. The first is to challenge the NOR. Was the vessel truly ready in all respects? Were hatches open, cranes operational, and cargo gear prepared? Was the NOR tendered at the correct time and to the correct party as specified in the charter party? A defective NOR can collapse the entire claim.
The second strategy is to claim exceptions. Did an excepted peril, such as a strike, ice, or mechanical breakdown, occur during laytime? The charterer must prove the event falls within the clause and, if the clause is an exception rather than an interruption, must also show causation. This is harder once demurrage has commenced, but not impossible if the charter party contains a clearly worded demurrage exception.
Third, argue the vessel was not "arrived." Under a berth charter party, the vessel must reach the berth. Under a port charter party, it must be within the port's commercial limits. If the vessel was waiting outside those limits, laytime may not have commenced. Fourth, check for set-off or counterclaim. Did the shipowner cause delay through unseaworthiness, crew incompetence, or equipment failure? Finally, use the "interruptions" argument if the charter party wording supports it. If the clause merely requires the excluded state of affairs to exist, the charterer's burden is lighter, and the claim may be reduced or defeated.
The market for demurrage management software has matured, and in 2026, UK-based traders and shipowners have access to dedicated platforms that automate much of the calculation, tracking, and dispute workflow. Tools such as Voyager Portal, ClearDemurrage, and Veson Nautical offer automated NOR and laytime tracking, real-time demurrage accrual dashboards, and integration with charter party data and email correspondence.
When selecting a platform, look for features that support English law default clauses and UK time zone calculations. The ability to generate time-stamped records of NOR tender and cargo operations is invaluable in arbitration. For those managing high volumes of fixtures, a platform that centralises demurrage data can reduce the administrative burden and help identify patterns of delay. CocoonDEM offers a resource for evaluating these tools, helping freight forwarders and traders understand how to simplify cost visibility and reduce disputes through better tracking.
Can a demurrage claim be disputed after payment? Yes. Under English law, payment made under protest preserves the right to challenge the claim later in arbitration or court proceedings. Does demurrage apply to container shipping? Yes, but it is a separate concept. Container detention at terminals is governed by terminal tariffs and carrier standard terms, not voyage charter parties. What is the typical demurrage rate for a Supramax in 2026? Rates vary with market conditions, but daily figures typically range from $8,000 to $15,000 depending on vessel size, route, and supply-demand balance. How long does a demurrage claim take to settle? Straightforward claims may settle within 30 to 60 days. Disputed claims, particularly those proceeding to LMAA arbitration in London, can take 6 to 18 months to reach a final award.
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