Gyn
Encyclopedia
A gyn is a form of three legged lifting device used on sailing ship
Sailing ship
The term sailing ship is now used to refer to any large wind-powered vessel. In technical terms, a ship was a sailing vessel with a specific rig of at least three masts, square rigged on all of them, making the sailing adjective redundant. In popular usage "ship" became associated with all large...

s. It provides more stability than a derrick
Derrick
A derrick is a lifting device composed of one tower, or guyed mast such as a pole which is hinged freely at the bottom. It is controlled by lines powered by some means such as man-hauling or motors, so that the pole can move in all four directions. A line runs up it and over its top with a hook on...

 or sheers
Sheers
Sheers are a form of two-legged lifting device, that were used by sailboats and dockyards for tasks such as lifting masts and heavier parts of the rigging on board....

, and requires no rigging
Rigging
Rigging is the apparatus through which the force of the wind is used to propel sailboats and sailing ships forward. This includes masts, yards, sails, and cordage.-Terms and classifications:...

 for 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 ropeway
Ropeway
A ropeway is a form of naval lifting device used to transport light stores and equipment across rivers or ravines. It comprises a jackstay, slung between two sheers or gyns, one at either end, from which is suspended a block and tackle, that is free to travel along the rope and hauled back and...

.

Gyns have also been used on land as part of the equipment to help assist water being pumped out of water wells in the Sinai Peninsula.

Two legs, called cheeks, are bound together as in the sheerlegs. The third spar is called the prypole and is fixed under the cheeks. Only four pulleys are required; three as splay tackles and the fourth one as lifting purchase. A timber hitch
Timber hitch
The timber hitch is a knot used to attach a single length of rope to a piece of wood. This knot is easily undone after use.To make the knot, pass the rope completely around the wood. Pass the running end around the standing part, then through the loop that you have just formed. Make three turns...

of six figure-of-eight turns and a finishing clove hitch lash the crutch but not too tight because the cheeks need some room to spread their heels. The cheeks of the gyn are now ready to spread and to be erected, the cheek splay tackle is hauled tight and then the other adjacent splay tackles can be lashed. At the sides, the gyn is unstable and it is crucial that the cargo is not swung out of the base triangle; consequently the gyn is only for lifting cargo vertically.
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