Posted by John Hatcher on January 05, 2001
This is an old nautical term.
The Devil - Caulker's name for the seam in the upper deck planking next to a ship's waterways. There was very little space to get at this seam, making it a difficult and awkward job. This is the origin of the expression "Between the devil and the deep blue sea, since there is only the thickness of the ship's hull planking between this seam and the sea. also known as the garboard seam.