A gyn is an improvised three legged lifting device used on sailing ships. It provides more stability than a derrick or sheers, and requires no rigging for support. Without additional support, however, it can only be used for lifting things directly up and down. Gyns may also be used to support either end of a . British Army artillery gunners used apparatus such as 'Bell's gyn' designed by John Bell (artillerist) or the 'Gibraltar gyn' for lifting artillery pieces.