Date: World War II (1940-1945)
The Navy authorized denim as a part of its uniform in 1901, but only following the fabric's spread to officers and sailors in 1914 did denim truly took off on the high seas. The major usage was during World War II, where, as an on-board fatigue, members of the Navy wore indigo blues as part of their uniform. Traditionally produced in 12 oz. cotton denim, the jacket (which is more of a shirt jacket) featured open top pockets at the hip, a shawl collar, and cuff placket. This was worn with straight leg dungarees to complete the uniform. Often times, during work or while on board, it would be common to see sailors not with the denim jacket, but with a chambray shirt (traditionally in a lighter indigo) that would have normally been worn under the uniform's jacket.