Jibboom

A jibboom (also spelled jib-boom) is a spar used to extend the length of a bowsprit on sailing ships. It can itself be extended further by a flying jib-boom. The heel (i.e. rear and lower) end of the flying jib-boom is attached to the jib-boom, and the heel of the jib-boom to the bowsprit. The point (i.e. higher and fore end) of the flying jib-boom is generally the fore-most extent of a ship. The jib- and flying jib- booms carry the tacks of the jib and flying jib sails, respectively, and the stay for the fore topgallant mast and the royal stay.

In yachts it is a boom attached to the foot of the jib, to keep the shape of the sail in different wind angles and to allow self tacking.