Chapter VIII: Blocks and Purchases

Parts of a block. Made and morticed blocks. Bull's-eye. Dead-eye. Sister-block. Snatch-block. Tail-block. Whip. Gun-tackle. Luff-tackle. Whip-upon-whip. Luff-upon-luff. Watch or tail-tackle. Runner-tackle.

Blocks are of two kinds, _made_ and _morticed_. A _made block_ consists of four parts,--the _shell_, or outside; the _sheave_, or wheel on which the rope turns; the _pin_, or axle on which the wheel turns; and the _strap_, either of rope or iron, which encircles the whole, and keeps it in its place. The sheave is generally strengthened by letting in a piece of iron or brass at the centre, called a _bush_.

A MORTICED BLOCK is made of a single block of wood, morticed out to receive a sheave.

All blocks are single, double, or three-fold, according to the number of sheaves in them.

There are some blocks that have no sheaves; as follows: a _bull's-eye_, which is a wooden thimble without a sheave, having a hole through the centre and a groove round it; and a _dead-eye_, which is a solid block of wood made in a circular form, with a groove round it, and three holes bored through it, for the lanyards to reeve through.

A SISTER-BLOCK is formed of one solid piece of wood, with two sheaves, one above the other, and between the sheaves a score for the middle seizing. These are oftener without sheaves than with.

SNATCH-BLOCKS are single blocks, with a notch cut in one cheek, just below the sheave, so as to receive the bight of a fall, without the trouble of reeving and unreeving the whole. They are generally iron-bound, and have a hook at one end.

A TAIL-BLOCK is a single block, strapped with an eye-splice, and having a long end left, by which to make the block fast temporarily to the rigging. This tail is usually selvageed, or else the strands are opened and laid up into sennit, as for a gasket.

A TACKLE is a purchase formed by reeving a rope through two or more blocks, for the purpose of hoisting.

A WHIP is the smallest purchase, and is made by a rope rove through one single block.

A GUN-TACKLE PURCHASE is a rope rove through two single blocks and made fast to the strap of the upper block. The parts of all tackles between the fasts and a sheave, are called the _standing parts_; the parts between sheaves are called _running parts_; and the part upon which you take hold in hoisting is called the _fall_.

A WHIP-UPON-WHIP is where the block of one whip is made fast to the fall of another.

A LUFF-TACKLE PURCHASE is a single and a double block; the end of the rope being fast to the upper part of the single block, and the fall coming from the double block. A luff-tackle upon the fall of another luff-tackle is called _luff-upon-luff_.

A WATCH-TACKLE or TAIL-TACKLE is a luff-tackle purchase, with a hook in the end of the single block, and a tail to the upper end of the double block. One of these purchases, with a short fall, is kept on deck, at hand, in merchant vessels, and is used to clap upon standing and running rigging, and to get a strain upon ropes.

A RUNNER-TACKLE is a luff applied to a runner, which is a single rope rove through a single block, hooked to a thimble in the eye of a pennant.

A SINGLE BURTON is composed of two single blocks, with a hook in the bight of the running part. Reeve the end of your rope through the upper block, and make it fast to the strap of the fly-block. Then make fast your hook to the bight of the rope, and reeve the other end through the fly-block for a fall. The hook is made fast by passing the bight of the rope through the eye of the hook and over the whole.