Definition
Running days are calendar days counted consecutively without interruption — including Sundays and public holidays. The term appears almost exclusively in maritime and shipping law, where it governs the calculation of lay days (the time allowed to load or unload a vessel) and demurrage (the penalty for detaining a vessel beyond that allowance).
When a charter-party specifies that lay days run as "running days," every day on the calendar counts from the moment the period begins — weekends and holidays included — until the allowed period expires. This is the baseline rule in the absence of contrary custom or express agreement.
Common Language
Modern common usage (Wiktionary): Plural of "running day" — no independent definition offered; treated as self-explanatory.
Historical common usage (Webster's 1913): Not defined as a legal term of art; "running" in ordinary usage connotes continuous motion or uninterrupted sequence.
The common-language sense of "running" as simply "continuous" is not wrong, but it understates what is legally at stake. The precision matters because the alternative — working days — excludes Sundays and holidays, producing a materially longer allowed period. Choosing the wrong calculation method can shift thousands of dollars in demurrage liability. The ordinary reader would not appreciate that "running" in this context is a term of art carrying a specific legal default rule.
Common Confusion
Running days vs. working days: This is the central distinction in charter-party disputes. Working days exclude Sundays and holidays; running days do not. Because lay day clauses were historically drafted loosely, courts frequently had to determine which method applied. The default rule — in the absence of controlling custom or express agreement — favors running days. But by the custom of London, lay days are presumed to mean working days. Researchers must not assume either standard applies without examining the applicable custom and the contract's express language.
Running days vs. lay days: "Lay days" is the broader concept — the total time allowed for loading and unloading. "Running days" describes the method of counting those days, not the allowance itself. A charter-party can specify lay days counted as running days, lay days counted as working days, or (in modern drafting) weather working days.
Why It Matters in Research
This term functions as a calculation rule embedded inside the larger framework of lay days and demurrage. Researchers approaching charter-party disputes from historical sources must watch for three things.
First, the custom-of-London rule. Rapalje & Lawrence explicitly notes that London custom treats lay days as working days by default, while the general legal default favors running days. Historical English cases applying the London custom should not be imported uncritically into American or other jurisdictions.
Second, the sources are not uniform. Bouvier defines running days as days counted "without any allowance for holidays," which aligns with the mainstream rule. But Burrill's entry conflates "running days" with lay days generally — describing them as days allowed for loading and unloading — rather than as a counting methodology. Burrill is less precise here than Black's or Rapalje & Lawrence, and researchers relying on Burrill alone may miss the working-days/running-days distinction entirely.
Third, modern shipping contracts have largely supplanted the running-days default through express drafting. Standard form charter-parties (including GENCON and similar templates) typically specify the counting method, weather working days, or SHINC (Sundays and Holidays Included) and SHEX (Sundays and Holidays Excluded) designations. Historical case law resolving ambiguous lay day clauses may be less relevant to contemporary disputes where the contract is express, but remains essential for construing older instruments and understanding how courts fill gaps.
The term is narrow in scope but consequential in application. A one-day error in the running-days calculation can determine whether demurrage is owed at all.
Historical Dictionary Support
All five source dictionaries agree on the core proposition: running days are consecutive calendar days including Sundays and holidays. There is no meaningful disagreement among them on the fundamental definition.
The sources diverge in depth and precision. Black's (both editions) and Rapalje & Lawrence treat the term as a term of art in the working-days/running-days opposition and ground it explicitly in charter-party practice. Rapalje & Lawrence is the most analytically useful source here, presenting the term in its functional context — the demurrage clause — and flagging the London custom exception. Black's 2nd edition adds case citations (Brown v. Johnson, 10 Mees. & W. 334; Crowell v. Barreda, 16 Gray (Mass.) 472) that confirm the rule's English and American reception.
Bouvier is reliable on the definition but thin on context. Burrill is the weakest source for this term: its entry describes lay days generally rather than isolating running days as a counting method. Researchers should treat Burrill's entry as background orientation, not primary authority on the distinction.
None of the historical dictionaries address modern charter-party conventions (SHINC/SHEX, weather working days), which is expected given their vintage. The evolution from a gap-filling common law default to an expressly negotiated contract term is not captured in any of these sources and must be sourced from shipping law treatises and modern practice.
Jurisdictional Note
The running-days default was recognized in both English and American courts, but the London custom exception (favoring working days) was a local English commercial rule not universally transplanted to American jurisdictions. American courts generally applied the running-days default in the absence of express agreement or controlling custom. Modern international shipping contracts are typically governed by the law specified in the charter-party, and practitioners should not assume any particular national default applies without checking the governing law clause.
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry directly addresses charter-party lay days or demurrage calculation. The matched entries (tax deficiency notices, real covenants, hit-and-run torts) are not relevant to this term.