The word "rig" comes from the Scandinavian word "rigga," which means to bind or wrap around. Rig has come to mean many more things to a sailor. The rigging of masts, yards and ropes of sailing ships; and for handling heavy weights and cargo, also as rigging a ship for heavy weather.
The rigging of a ship is broken down into standing and running rigging. Standing rigging are the stays and shrouds that support the mast. Running rigging is all movable ropes rove through blocks.
The term "jury rig" meant the temporary arrangement of spars and sails to bring a dismasted vessel into port. Today it means rigging to handle heavy weights.
A block consists of one or more pulleys or sheaves fitted in a wood or metal frame. Each block has one or more straps of steel or rope which strengthen the block and, in most cases, support the sheave pin. By means of a hook or shackle inserted in the strap, the block itself may be suspended or a load applied to the block. If the block has a becket to which the fall is spliced, the becket is also secured to the strap.
A block with a rope led over the sheave is convenient in applying power by changing the direction of the pull. Used in conjunction with rope and another block, it becomes a tackle (pronounced TAYK-el) and increases the power applied on the hauling part.
Nomenclature of the parts of blocks are; HOOK, PEA, OUTER STRAP, INNER STRAP, SWALLOW, SHEAVE, BREECH, SHELL, CHEEK, PIN, FACE, BECKET, THIMBLE. The size of blocks, designated in inches, is found by measuring the length of the cheek. Blocks are designed for use with a certain size of rope; they never should be used with rope of a larger size. Rope bent over a small sheave will be distorted, and any great strain will injure it and may even result in the rope wearing on the frame. A safe rule of thumb to find the size of block to use is to multiply the size of line by 3. Another rule of thumb is that the sheaves must be no smaller than 2 times the circumference of the line used. Head, Heel, and fairlead blocks are of the roller bearing type.
A cargo block is usually named for its location in the cargo rig. The block at the head of the boom through which the whip runs is called the head block. That at the foot which fairleads the wire to the winch is called the heel block. A small single sheave block in the middle of most booms is called the slack wire block. Blocks in the topping lift are called upper and lower topping lift blocks.
A fairlead block, called a cheek block, is permanently fixed by welding or bolting one cheek to a bulkhead, davit, etc. Another fairlead block is a snatch block, which is cut at the swallow (hole the line reeves through), hinged on one side, and fitted with a hasp on the other. This permits the block to be opened and clapped on a line rather than reeving the end of the line through. Tail blocks are single blocks usually used alone with a whip or as a runner. Tackles are designated by the number of sheaves in the blocks that are used to make the tackle.
SINGLE WHIP: A single whip consists of one h.-lIw block fixed to a support with a rope
passing over the sheave.
RUNNER: This consists of a single block but the block is free to move, and one end of the rope is secured to the support with weight attached to the block.
GUN TACKLE: This tackle is made up of two hlocks, and takes its name from the use made of it in hauling muzzle loading guns back into battery after the guns are fired reloaded.
LUFF TACKLE (JIGGER): A double and a single block make up this tackle.
TWOFOLD PURCHASE: which is made up of two double blocks.
DOUBLE LUFF TACKLE: Consists of a treble and double block.
THREEFOLD PURCHASE: There is a Right angle method and a Parallel method of reeving both the double luff and the threefold purchase. Of these two methods of reeving, the right angle is considered the better as it reduces the chances of the various parts of the rope chafing on each other.
