Tintin au pays de l'or noir
Black or navy blue caps of this type served as workwear for merchant navy sailors throughout the 20th century. Caps with decorative gold braid, either in the standard navy blue or with a white top, were favored by the skippers of sailing yachts, motor boats, and other small pleasure craft. From the 1930s until the 1970s a waterproof version, known as a mechanic's cap, was worn with a blue boiler suit (coveralls) as part of the uniform for truckers, gas station employees and breakdown men. In the 1950 edition of Tintin and the Land of Black Gold, Thomson and Thompson wear these caps when they go undercover as Autocart mechanics.