It was customary from Elizabethan times to divide the ship’s company into two watches – starboard and port – one of which is always on duty watch.

Watch stripes were lengths of material worn round the shoulder seam of jumper or frocks worn by sailors to show to which watch a man belonged. The starboard watch wore the stripes on the right shoulder, the port watch on the left shoulder. On blue clothing the stripe was red, on white clothing it was blue. They were abolished about 1895 but continued to be used on boys’ training ships until 1907.