it's all plain sailing
Preserved but no longer current.
It's perfectly straight- forward; there need be no hesitation about the course of action. A nautical phrase which should be written plane, not plain. Plane sail- ing is the art of determining a ship's position on the assumption that the earth is flat and she is sailing, therefore, on a plane, instead of a spherical surface, which is a simple and easy method of computing distances.
Era: ca. 1898 (Victorian)
Sources & notes
Reproduced from Brewer’s Dictionary of Phrase and Fable (1898 edition, public domain; archive.org, retrieved 2026-07-31; OCR text, minor errors possible). Reflects the scholarship and attitudes of its era.
Common questions
What does “it's all plain sailing” mean?
It's perfectly straight- forward; there need be no hesitation about the course of action. A nautical phrase which should be written plane, not plain. Plane sail- ing is the art of determining a ship's position on the assumption that the earth is flat and she is sailing, therefore, on a plane, instead of a spherical surface, which is a simple and easy method of computing distances.
Is “it's all plain sailing” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.