Since before the Napoleonic wars it was the custom of HM ships to fly a paying-off pennant at the main truck when they left their fleet to return to their home port to pay off. Custom ordained that the length of the pennant should equal the length of the ship if she left station at the end of a normal period of foreign service. If, however, a commission had been extended, the length of the pennant was increased in proportion to the extra length of service (e.g. for a commission of 2 years extended to 2 years and 2 months the length of the pennant would be the length of the ship plus 1/12th). It was similar to, and flown in place of, the masthead pennant, and was displayed by a ship from a foreign station when entering or leaving harbours during her passage home, and by a ship of the fleet on leaving for and arriving at her home port. It was also the custom on all stations for a ship to fly this pennant on the Sunday preceding her departure, or, if already in her paying-off port, on the Sunday preceding the day on which she paid off.
