Etymology From plain (adjective) + sailing. Sense 2 (“something that is easy, simple, or straightforward”) is attested slightly later than plain-sailing (adjective), and so could have been derived from it.
1
Nautical, Transport The navigation of waters free from hazards or unfavourable winds.
2
Nautical, TransportObsolete Obsolete spelling of plane sailing (“a technique for navigation using the assumption that the journey occurs over a plane or flat surface rather than the actual curved surface of the Earth, which is sufficiently accurate over short distances”).
[…] I hired a Tonquineſe for about a Dollar to be my guide. This, tho but a ſmall matter, vvas a great deal out of my Pocket, vvho had not above 2 Dollars in all, vvhich I had gotten on board, by teaching ſome of our young Seamen Plain Sailing.1699, William Dampier, “Some Vessels Sent from Cachao to Tenan to Fetch Rice. […]”, in Voyages and Descriptions. Vol. II. […], London: […] James Knapton, […], →OCLC, part I (His Voyage from Achin in Sumatra, to Tonquin, […]), page 90:
[…] Me[r]cators Sailing gives the correct Difference of Latitude and Longitude both; Middle Latitude Sailing, only the correct Difference of Longitude; Plain Sailing gives neither correctly; and therefore their Merits are in Proportion.1735, Benjamin Martin, “The Use of Decimals in Plain Trigonometry, and Other Mathmatical Sciences Depending thereon”, in A New Compleat and Universal System or Body of Decimal Arithmetick, […], London: […] J[ohn] Noon, […], →OCLC, page 322:
2 more examples
I doubt as hovv I've ſteered by a vvrong chart, d'ye ſee—as for the matter of the ſciences, to be ſure, I knovv plain ſailing and mercator; and am an indifferent good ſeaman, […]1760 January – 1761 December, [Tobias George Smollett], “In which the Knight Resumes His Importance”, in The Life and Adventures of Sir Launcelot Greaves. […], Dublin: […] James Hoey, junior, published 1762, →OCLC, page 78:
[W]e have determined to go by way of Lisbon, […] and so on our old route to Malta and Constantinople, if so be that Captain Kidd, our gallant commander, understands plain sailing and Mercator and takes us on our voyage all according to the chart.1809 June 25, Lord Byron, “Letter XXXV. To Mr. Henry Drury.”, in Thomas Moore, editor, Letters and Journals of Lord Byron: With Notices of His Life, […], volume I, London: John Murray, […], published 1830, →OCLC, page 188:
3
Figuratively Something that is easy, simple, or straightforward; something that offers no difficulties or trouble.
[H]e ſhould give himſelf fair play, by trying his hand vvith the rudiments, vvhich vvould no ſooner be run over, than the reſt vvould become plain ſailing: […]1796, [Frances Burney], “Studies of a Grown Gentleman”, in Camilla: Or, A Picture of Youth. […], volume I, London: […] T[homas] Payne, […]; and T[homas] Cadell Jun. and W[illiam] Davies (successors to Mr. [Thomas] Cadell) […], →OCLC, book I, page 73:
After this [the whale's tongue] was hoisted in, the rest of the way was plane sailing, the blubber of the body being cut and peeled off, in huge unbroken strips, as the carcass rolled over and over, being heaved on by the windlass, then hooked into by the blubber hooks, and hoisted in by the men all the time heaving at the windlass.1850, Henry T[heodore] Cheever, “Raising and Cutting-in Whales”, in The Whale and His Captors; or, The Whaleman’s Adventures, and the Whale’s Biography, […], New York, N.Y.: Harper & Brothers, […], →OCLC, page 58:
4 more examples
Life is not plain-sailing, and writers on Life must not put themselves in antagonism with their subject. Life is the sphinx; and they who see no mystery in her utterances—they who essay not to guess her riddles—what can their lot be but swift destruction?1853, “An Æsthetic Tea”, in William Harrison Ainsworth, editor, Ainsworth’s Magazine, volume XXIII, London: Chapman and Hall, […], →OCLC, page 78:
Yes, it was all plain sailing now. How long had it taken him to win her—three years? He had loved her for three years.1887, H[enry] Rider Haggard, “Frank Muller’s Familiar”, in Jess, London: Smith, Elder, & Co., […], →OCLC, page 251:
Hovstad. Do you think that will be all such plain sailing? / Dr. Stockmann. Plain sailing or no, it has got to be done, anyway.1911, Henrik Ibsen, “An Enemy of the People: A Play in Five Acts”, in R[obert] Farquharson Sharp, transl., edited by Ernest Rhys, Ghosts; The Warriors at Helgeland; An Enemy of the People (Everyman’s Library; no. 552), London: J[oseph] M[alaby] Dent & Sons; New York, N.Y.: E[dward] P[ayson] Dutton & Co., published 1949, →OCLC, Act II:
Let us admit that without the proper clues the gospels are, to a modern educated person, nonsensical and incredible, whilst the apostles are unreadable. But with the clues, they are fairly plain sailing. Jesus becomes an intelligible and consistent person.1915 December (date written), [George] Bernard Shaw, “Androcles and the Lion. Preface on the Prospects of Christianity.”, in Androcles and the Lion, Overruled, Pygmalion, London: Constable and Company, published 1916, →OCLC, pages xxiv–xxv:
Related terms
plain-sailing
plain-sailing
adj
Etymology From plain (adjective) + sailing. Sense 2 of plain sailing (“something that is easy, simple, or straightforward”, noun) is attested slightly later than the adjective, and so could have been derived from it.
1
Easy, simple, straightforward.
[…] I took an uncommon fancy to him. He's a straightforward, plain-sailing fellow. I shall be very glad to see him again.1873, Louisa Parr, “Rays of Hope”, in Hero Carthew or The Prescotts of Pamphillon […] (Leisure Hour Series), New York, N.Y.: Holt & Williams, →OCLC, page 91:
[W]hat was the mainspring of her mind—round what axis did it revolve—that was what puzzled him. Clearly enough it was not like most women's, least of all like that of happy, healthy, plain-sailing Bessie.1887, H[enry] Rider Haggard, “Bessie is asked in Marriage”, in Jess, London: Smith, Elder, & Co., […], →OCLC, page 31:
1 more example
But the plain-sailing tradesman who must be taken as the typical manager (for the west end of London is not the whole theatrical world) is by no means equally qualified to judge whether a play is safe from prosecution or not.1909 (date written), [George] Bernard Shaw, “The Shewing-Up of Blanco Posnet. Preface.”, in The Doctor’s Dilemma, Getting Married, & The Shewing-Up of Blanco Posnet, London: Constable and Company, published 1911, →OCLC, page 303: