A jack staff (also spelled as jackstaff) is a small vertical

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

(pole) on the bow of a ship or smaller vessel on which a particular type of

flag A flag is a piece of fabric (most often rectangular or quadrilateral) with a distinctive design and colours. It is used as a symbol, a signalling device, or for decoration. The term ''flag'' is also used to refer to the graphic design empl ...

, known as a

jack Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, ...

, is flown. The jack staff was introduced in the 18th century. A jack is typically flown from military vessels (including submarines) while at anchor or moored pierside, but not while underway. Civilian vessels (such as private yachts and sailboats) have been known to fly the jack of the nation of their homeport, also from a jack staff, while moored or at anchor.

References

Sailing rigs and rigging Nautical terminology {{Flag-stub