Many sailors often wear, while on duty on board, navy blue work trousers and navy blue work shirts. In the Dutch Royal Navy this working dress uniform is called "BoordTenue" which consists of a dark navy blue work shirt with zip-pockets on the breast and ditto work trousers. In the British Royal Navy this dress is called "Royal Navy Personal Clothing System (RNPCS)" which replaces the former "Action Working Dress".
In the two uppermost images below you see a doll wearing the Dutch Royal Navy's BoordTenue Working Dress Uniform. In the two images below the doll wearing BoordTenue I am wearing a general BoordTenue-like navy working dress uniform with a blue work shirt of the brand Mascot, type Detroit and a dark navy blue work trouser of the brand PortWest, type S887. All these four pictures were taken during the last Navy Days of the Dutch Royal Navy in Den Helder. In the lowermost picture you see a group of workers wearing a dark navy blue work shirt. In factories workers often wear blue work shirts, hence the term "Blue-collar Worker".
Because I am an enthusiast of the Dutch Royal Navy and shipping in general I like these dark navy working dress uniforms. I often wear them at home, at my work and when I am sailing on a Canoe.