“Between the devil and the deep sea” means on the horns of a dilemma; between Scylla and Charybdis; facing equally perilous dangers.
William Walker, in 1670, when compiling his “Phraseologia Anglo-Latina”; or “Phrases of the English and Latin Tongue”, included this expression in his list, probably finding it used by some earlier writer of Latin; but if so, his source is no longer known.
The phrase is listed, however, by James Kelly, in 1721, in his Complete Collection of Scotish Proverbs.
The view that it is of Scottish origin is supported by the fact that it is to be found in the account written by Colonel Robert Monro, a doughty Scot, “His Expedition with the worthy Scots Regiment called Mac-Keyes Regiment”, relating to his service under Gustavus Adolphus of Sweden between 1621 and 1632.
Monro described one engagement, in which he found himself exposed not only to the fire of the enemy, but also to Swedish guns that were not sufficiently elevated, and said, “I, with my partie, did lie on our poste, as betwixt the devill and the deep sea.”
This is the earliest English use of the phrase that has yet been found.
“Devil,” in this phrase, as also in “the devil to pay”, is a nautical term. In the days when hulls were of wooden construction, the term was applied to a seam between two planks which, because of its location or of its length, was especially accursed by sailors.
In this instance, “devil” probably referred to the seam on a ship’s deck nearest the side; hence, the longest seam on the deck, extending on a curve from stem to stern, and, from its location, a most dangerous one to calk or fill with pitch.
Anyone between the devil and the deep (blue) sea had a very narrow footing, a narrow margin for choice.
“Devil” was also applied to the seam that was at, or just above, the water line of a ship’s hull. Here again space was narrow and the margin of safety was negligible.