Laytime terms explained: SHINC, SHEX, WWD and the rest

Atlas Claims InsightsPublished 27 October 2026 · 9 min read

Laytime is the time charterers are allowed, without paying extra, to load or discharge the cargo. When it runs out, demurrage starts. Between those two points sit a handful of abbreviations that decide which hours count. Misreading one of them is one of the most common causes of overstated or understated demurrage claims.

How laytime is fixed

Charters set laytime in one of three main ways:

• A fixed period, for example 72 hours, or three days.
• A rate of loading or discharging, for example 10,000 metric tons per weather working day. Dividing the cargo quantity by the rate gives the allowance.
• Customary quick despatch (CQD), where no fixed time is set and the cargo must be handled as fast as is customary at the port. Delay claims under CQD are harder to prove and turn on what was reasonable.

Laytime is expressed as days or hours, and part days count pro rata unless the charter says otherwise.

Days, weekends and holidays

Charters often define the excepted period precisely, for example from 17:00 on Friday to 08:00 on Monday. Where they do, those hours govern rather than the general label. Which days are “holidays” depends on the law and custom of the port, so local calendars matter.

Unless used and even if used

Weekend exceptions are often qualified:

• “Unless used” (UU): if cargo is actually worked during the excepted period, the time used counts as laytime.
• “Even if used” (EIU): the excepted period does not count even if the cargo was worked.

Disputes arise over what “used” means, for example whether only the hours actually worked count, or the whole period. The statement of facts and the charter wording decide.

Weather working days

A weather working day is a working day, or part of one, on which weather does not prevent, or would not have prevented, the loading or discharging of the vessel. Time lost to bad weather is excluded whether or not the vessel was actually working cargo at the time. The test is whether the weather would have prevented work, not whether the vessel was in fact waiting for some other reason.

Related expressions such as “weather permitting” and “per weather working day of 24 consecutive hours” have their own established meanings. The safest approach is to check whether the charter incorporates a set of definitions, and to read the clause as a whole.

Once on demurrage, always on demurrage

Under English law, once laytime has expired, the exceptions that protect charterers during laytime normally stop applying. Weekends, holidays and most excepted events then count in full against charterers. This is often summarised as “once on demurrage, always on demurrage”.

Charters can change this, but only with clear words. Common examples include clauses giving half demurrage for delays caused by strikes or bad weather, and provisions stating that demurrage is not payable for time lost through the vessel’s own breakdown or fault. Our laytime statement calculator lets you mark each exception as counting in full, at half rate or not at all once the vessel is on demurrage.

Reversible and averaged laytime

• Reversible laytime gives charterers one combined allowance for loading and discharging. Time saved at the load port can be used at the discharge port, and demurrage is calculated on the total.
• Averaging calculates loading and discharging separately, then offsets time saved at one end against time lost at the other.

The two methods can produce different results, especially where despatch is payable or where the vessel is already on demurrage when it arrives at the second port. If the vessel is already on demurrage when it arrives at the second port, whether demurrage resumes on arrival or only after notice of readiness and any notice time depends on the charter wording, and English authority suggests the notice time may still apply.

Despatch: all time saved or working time saved

Despatch is a payment by owners to charterers for completing cargo operations before laytime expires, usually at half the demurrage rate. It is payable only if the charter provides for it.

• All time saved: despatch is calculated on the time from completion until laytime would have expired, including weekends and holidays that would have been excepted.
• Working time saved, or laytime saved: only the unused laytime counts, so excepted periods are left out.

On the same facts, all time saved usually produces a higher despatch figure.

Standard definitions

BIMCO, CMI, FONASBA and INTERCARGO publish the Laytime Definitions for Charter Parties 2013, which give agreed meanings for many of these terms. They apply only if the charter incorporates them. Otherwise, the words are interpreted according to the governing law and past decisions, which can produce different results. Before preparing or answering a claim, check which definitions apply and whether rider clauses amend them.

This guide is general information about the law of England and Wales as at October 2026. It is not legal advice and may not cover your situation. Atlas Claims is not a law firm; for advice on your legal rights or on litigation, consult a qualified solicitor.