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Who really said it

A Collision at Sea Can Ruin Your Entire Day

Not Thucydides — actually Cdr. W. B. ‘Bill’ Hayler, USN W. B. ‘Bill’ Hayler U.S. Navy officer · coined the line in 1960 · confessed the prank in 1971
Disputed In copyright

Thucydides never wrote this. A U.S. Navy officer, then a student at the Naval War College, composed the line in 1960 and told everyone it came from “Volume IX of the Peloponnesian War” — a work that runs to only eight books. He posted it in the wardroom of his destroyer, it reached print in U.S. Naval Institute Proceedings in March 1962 still credited to Thucydides, and he owned up in a San Francisco newspaper column in February 1971.

Last verified 1 Sep 2026 · how we verify · spot an error?

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Disputed credit — copy with the correction

“A Collision at Sea Can Ruin Your Entire Day” not Thucydides. Invented in 1960 by Cdr. W. B. "Bill" Hayler, USN, at the Naval War College, and credited by him to a nonexistent Volume IX of the Peloponnesian War (the History has eight books). Earliest printing located: U.S. Naval Institute Proceedings, March 1962; Hayler confessed in Herb Caen's San Francisco Chronicle column, 14 February 1971. Via Quotle.info

The slide-ready mistake: crediting this to Thucydides. Use the credit shown above instead.

Can you use it?

Still under copyright (rights held by W. B. Hayler or his estate; the March 1962 printing appeared in U.S. Naval Institute Proceedings (U.S. Naval Institute)). A short, credited quote is generally fine for talks, teaching, and internal decks; for commercial, published, or large-scale reuse, get permission.

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In context

Evoking the world of W. B. 'Bill' Hayler — Naval War College student, 1960 · commanding officer, USS Buck (DD-761). Theme: "A Collision at Sea Can Ruin Your Entire Day". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.

Minimalist

Minimalist editorial slide for the quote "A Collision at Sea Can Ruin Your Entire Day". Clean background, a single muted accent color, generous negative space, subtle paper or linen texture, no literal illustration — let the words carry it. Reserve clear space for a serif quote and a small credit line. No lettering in the image itself.

Provenance

Where the line actually first appears

Coined
1960, U.S. Naval War College — by the author’s own account
First located in print
U.S. Naval Institute Proceedings, March 1962
Credited to
“Thucydides 471–400 B.C.” — a fiction; the History runs to eight books, not nine
Confession
Herb Caen’s column, San Francisco Chronicle, 14 February 1971

“A collision at Sea can ruin your entire day.” Thucydides 471-400 B.C. (Sign posted in wardroom of USS Buck DD-761) Submitted by Commander W.B. Hayler, U.S. Navy Proceedings, March 1962

The filler item as transcribed by Quote Investigator from U.S. Naval Institute Proceedings, March 1962 — the earliest sea-collision version its researchers located, and submitted by the man who later admitted inventing it.

Quote Investigator: A Collision at Sea Can Ruin Your Entire Day

How we verified this

  • 1957 — the airborne ancestor. Speaking on air safety at a National Guard Association conference, Maj. Gen. Roger J. Browne, Jr. relayed a line from one of his jet-training headquarters: “A mid-air collision will ruin your entire day.” Quote Investigator calls this the earliest example of the class it has located ↗, and the phrase recurs in the Navy safety review Approach in 1958 and on the safety posters a 1960 novel describes.
  • March 1962 — the sea version reaches print. U.S. Naval Institute Proceedings runs the line as a page-foot filler, credited to Thucydides and sourced to a sign in the wardroom of USS Buck (DD-761) — submitted by Commander W. B. Hayler himself ↗. A Chicago newspaper boating column repeated it that September, and by 1966 it had been canonised in a naval quotation dictionary and quoted in Ebony in a profile of Commander Samuel L. Gravely.
  • 14 February 1971 — the author confesses. Herb Caen’s San Francisco Chronicle column reports that Navy Capt. W. B. ‘Bill’ Hayler made it up at the Naval War College in 1960 because a professor “quoted him all day long”, and attributed it to a ninth volume of a work with eight. Fred R. Shapiro reproduced the column in full in 2010 ↗.
  • The negative check. The sentence is in no book of the History of the Peloponnesian War, which was subdivided into eight books ↗ and can be read end to end in English at Project Gutenberg ↗.
In copyright

Because the line is not ancient text, no public-domain status can ride on Thucydides. Its author is identifiable — Hayler composed it in 1960 — and the earliest printing located is U.S. Naval Institute Proceedings of March 1962, comfortably after the 1931 U.S. public-domain cutoff, so it should be treated as in copyright to Hayler or his estate. A single-sentence maxim is thin material for any actual claim, but that is a judgement about enforceability, not about its date.

Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.

Fact-check

Who gets the credit, and why they shouldn’t

This is a rare case where the hoaxer confessed in print, so the misattribution can be traced from invention to admission. It nonetheless still appears on wardroom plaques, in bridge notices and in quotation collections under the wrong name.

Thucydides Fabricated

The line appears nowhere in the History of the Peloponnesian War. Wikiquote lists it in its Misattributed section ↗, recording that it was invented by a student at the US Naval War College in 1960 and then quoted as genuine Thucydides in Reader’s Digest in 1962.

“Volume IX of the Peloponnesian War” Nonexistent

Hayler built the tell into the joke: he told people it came from a ninth volume, and the History was subdivided into eight books ↗. Anyone who checked the reference would have caught it; for years nobody did.

“Horowitz’s First Law of the Admiralty” Unexplained

New York magazine printed the maxim under that name in 1978. Quote Investigator says plainly that it does not know how or why Horowitz was linked to the saying ↗ — and neither do we.

“entire day” vs “whole day” Drift

Both forms circulate. The 1962 Proceedings filler and the Chicago newspaper reprint read “entire day”; the airborne ancestors of 1958 and 1960 read “whole day”, and Wikiquote lists the ‘whole day’ form ↗. No version is the ancient one, because there is no ancient one.

The idea is not Thucydidean and the words are not his: the sentence was written in 1960 by a U.S. Navy officer who said so himself in 1971 ↗, and it descends from mid-century American flight-safety posters rather than from fifth-century Athens.

Context

Why a fake ancient quote outran the real ones

The joke works because the sentence sounds exactly like what a modern reader expects an ancient Greek to sound like: flat, unhurried, faintly grim. That is also what made it unfalsifiable in practice. Nobody carrying a card in a wardroom was going to open eight books of Athenian naval history to check, and the false citation — a ninth volume — was designed to send anyone who did to a shelf that ends one book earlier.

Its real family tree is American and airborne. Quote Investigator traces the pattern to 1957, when a general quoted the line “A mid-air collision will ruin your entire day” from one of his own jet-training commands; the Navy’s aviation safety review printed a version in 1958, and a 1960 novel about commercial aviation refers to it as an old safety poster. Hayler’s contribution was to move it from the air to the sea and give it a 2,400-year-old author.

“Of course, Thucydides only wrote eight volumes.” — Capt. W. B. Hayler, 1971

How far it got before anyone checked

Hayler’s own tally of the spread, given to Herb Caen in 1971: he posted it on the bridge when he took command of USS Buck in 1960; Reader’s Digest picked it up in 1962 and paid him five dollars; and Navy advertising for a rules-of-the-road publication ran the quotation as genuine.

Independently of Hayler’s account, the attribution kept propagating through respectable channels: a boating column in the Chicago Daily Tribune in September 1962 relayed it from Proceedings as a comment “originated by Thucydides”; a 1966 Dictionary of Military and Naval Quotations filed it under “Collision” as “Attributed to Thucydides”; and a 1966 Ebony profile described Commander Samuel L. Gravely keeping a card with the line on it.

The maxim also mutated back toward the air. During Apollo 10 in 1969, commander Thomas P. Stafford, discussing the discarded lunar module stage below the spacecraft, remarked that a collision was highly improbable but “would sure ruin your whole day if it happened.”

Explore

Filed under

More provenance-checked quotes on the same theme, each with its reuse status.

Wisdom Humility Truth

Go further

Dig deeper

Trusted places to keep pulling the thread — primary archives, fact-checks, and scholarship. We show how we used each one before you leave.

Quote Origin: A Collision at Sea Can Ruin Your Entire Dayquoteinvestigator.com

The anchor investigation: the full chronology from the 1957 mid-air version through the March 1962 Proceedings filler, the 1966 dictionary and Ebony citations, and Hayler’s 1971 confession.
Thucydides — Misattributeden.wikiquote.org

Lists the maxim among the fake Thucydides quotations, with the ‘Book IX’ tell and the 1960 Naval War College origin.
Quotes Uncovered: When Ships Collidefreakonomics.com

Fred R. Shapiro reproduces Herb Caen’s 14 February 1971 column verbatim, including Hayler’s confession in his own words.
The History of the Peloponnesian War (Crawley translation)gutenberg.org

The complete work in English, free to read — the negative check that the sentence is not in Thucydides.
Thucydides, The Peloponnesian Warperseus.tufts.edu

Searchable scholarly text of the History, navigable book by book — eight books, no ninth.
Thucydidesen.wikipedia.org

Biography of the Athenian historian and general (c. 460 – c. 400 BC) and confirmation that his History was subdivided into eight books.

The man who actually wrote it

The prankster who out-quoted Thucydides

W. B. ‘Bill’ Hayler

U.S. Navy officer · Naval War College student, 1960 · commanding officer, USS Buck (DD-761)

W. B. ‘Bill’ Hayler was a United States Navy officer who, by his own account, invented the most-quoted sentence in the maritime world while sitting through lectures at the Naval War College in 1960. His history professor, he said, was “absolutely hooked on Thucydides” and quoted him constantly — so Hayler wrote a line of deadpan understatement, credited it to a ninth volume of the Peloponnesian War that does not exist, and waited. He posted it on the bridge when he took command of the destroyer USS Buck, submitted it to U.S. Naval Institute Proceedings, and watched it escape: Reader’s Digest reprinted it and paid him five dollars, and Navy advertising put it in print as genuine. By 1971 he was a captain at the California Maritime Academy in Vallejo, and told columnist Herb Caen the whole thing was his.

For writers & researchers

Cite this

Primary documentation

Garson O’Toole, “Quote Origin: A Collision at Sea Can Ruin Your Entire Day,” Quote Investigator, 21 November 2010, quoteinvestigator.com/2010/11/21/collision-at-sea/. Earliest printing of the sea version located by QI: U.S. Naval Institute Proceedings 88, no. 3 (March 1962): 65, submitted by Commander W. B. Hayler, U.S. Navy. Hayler’s confession: Herb Caen, San Francisco Chronicle, 14 February 1971, reproduced in Fred R. Shapiro, “Quotes Uncovered: When Ships Collide,” Freakonomics, 8 July 2010.

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Quotle.info. “Who really said ‘A Collision at Sea Can Ruin Your Entire Day’?” Last verified 1 Sep 2026. https://quotle.info/who-said/a-collision-at-sea-can-ruin-your-entire-day/

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