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.
Alternately, a tripod lashing may be used to form the tripod, with the heel of the center spar pointing in the opposite direction of the cheeks to ensure a solid apex when raised.
A timber hitch, six figure-of-eight turns, and a finishing clove hitch lash the cheeks into a crutch but not too tight because the cheeks need some room to spread their heels.
The cheek splay tackle is hauled tight and then the two adjacent prypole splay tackles can be rigged and hauled as apex of the gyn is raised.