BLOCK. 



605 



Block. 



Plate 

 LVII. 



rig. i. 



Plate 

 LVII. 

 Fig. 2. 



Plate 

 J.VII. 

 Fig. 3. 



Snatch block, is a single sheave, with a notch cut 

 ' through one of its cheeks, to admit the rope or fall 

 to be lifted in a^J out of the block without putting 

 its end through first. ( See a figure of this in Plate 

 LVII. Fig. 1.) The strap does not in this surround 

 the block, but is put through a hole bored through 

 the divided end. The figure is represented with two 

 tails, which may be made up for a hook, a thimble, 

 or eye, according to the situation where it is to be 

 used, which is generally for the main or fore sheet 

 blocks of square rigged vessels. It is a convenient 

 block for heaving any rope in the navy. The snatch 

 blocks are iron bound, terminating at the notched 

 end of the block, with a swivel hook or an eye bolt, 

 large enough to receive several turns of lashing, 

 which fastens the block to its fixed support. That 

 part of the strap over the notch in the side lifts up 

 with a hinge, and is confined down, when the rope is 

 in the block, by a small pin put across through the 

 end of the pin of the sheave, which projects up from 

 the block sufficiently to pass through an eye made in 

 the hinge part of the strap. The strap on the other 

 part of the block is let into the block, and confined 

 by the pin and some nails. These blocks are used for 

 heavy purchases, where a warp or hawser is brought 

 to the capstan. See Plate LVII. Fig. 2. 



Deep sea line block, is a small wooden snatch block, 

 about from nine to eleven inches long. 



Cheek blocks are half shells, bolted against the 

 mast heads ; the chief bolt serves for the pin of the 

 sheave ; they receive the halyards and stays of their 

 respective masts. 



D blocks, are lumps of oak in the form of the letter 

 D, from 12 to 16 inches long, and 8 or 10 feet 

 wide ; they are bolted to the ship's side in the chan- 

 nels to receive the hits. 



Long tackle block, are two single sheaves placed one 

 above the other in the same shell. ( See Fig. 3. Plate 

 LVII.) The lower sheave is only ^ds the size of the 

 other; it is used in combination with a common single 

 block, to form the long tackle, for loading, or any 

 other purchase. In the navy and East India service 

 they are used as yard tackles. The rope is reeved 

 through it in the same manner as it would be through 

 a common double block ; but it is preferred where 

 it is convenient, because the strap being in the centre 

 of the resistance, it hangs more steadily than when 

 the sheaves are on one pin. 



Clue garnet blocks. These are single sheaves sus- 

 pended from the yards by a strap with two eyes ; a 

 lashing surrounds the yard and passes through the 

 eyes, so as to suspend the block beneath the yard; 

 these blocks receive the clue garnets or ropes which 

 haul up the clues of the sail ; this is applied to the 

 main and fore yard. 



Clue line blocks are for the same purpose as the 

 preceding, but applied to the top-sails, top-gallant, and 

 sprit-sails. A great improvement has lately been made, 

 in these blocks, by Mr Brunei, inventor of the block 

 machinery at Portsmouth. The old clue line and clue 

 garnet blocks, (for they are the same except in size,) 

 was a single sheave block, strapped with two eyes as 

 above ; a knot was made in the end of the clue line 

 or garnet, just at the place where it was attached to 

 the clue of the sail, to prevent the corner thereof be- 



ing drawn into the block. This was not effective, and 

 frequent inconvenience arose ; for the sail being so 

 constantly in motion, the rope had a great tendency 

 to get entangled with the sail, and drawn over the 

 sheave. The improved block in question is shewn in 

 Plate LVIII. Fig. 1. The two holes ataa, are where Plate 

 the rope goes in and out again. The she3ve is si- LVIII. 

 mated in the centre of the block, so as to be wholly Fi g- ' 

 inclosed except a mortice at b, where the sheave is 

 put in. The strap surrounds the lower part of the 

 block ; then both ends pass through a hole in the up- 

 per part about c, crossing each other. They are then 

 formed into an eye, by which the block is suspended 

 from the yard. By this means no accident can happen, 

 as the garnet, or rope, is so inclosed in the block, 

 that it cannot be deranged by any violence, nor the 

 sail be drawn into the block. 



Main sheet block is used for the sheet tackle of 

 the main-sail-booms of small vessels. The pin projects 

 from each side of the block, being in all the same 

 length as the block ; the fall or rope of the tackle is 

 belayed or twisted round this pin, to stop it. This 

 block is either single or double, and has a hole through 

 the end to receive its strap. 



Monkey blocks are sometimes* used on the lower 

 yards of small merchant ships, to lead (into the mast, 

 or down upon the deck) the running rigging be- 

 longing to the sails. The shells are made of ash or 

 elm. Some are only small single blocks attached by 

 a strap and iron swivel to iron straps, which embrace 

 and nail to the yard the block turning to lead the 

 small running ropes in any direction ; others are near- 

 ly eight square, with a roller working in the middle, 

 and a wooden saddle beneath to fit and nail to the 

 yard. 



Nine pin blocks are used to lead the running rope 

 in an horizontal direction. The shells, made of ash 

 or elm, resemble the form of a nine-pin, though flat- 

 ted on the sides. Their lengths are generally confined 

 to the place in which they are fixed ; and this is for 

 the most part under the cross pieces of the fore- 

 castle, and quarter-deck bitts. The breadth of the 

 block, sheave, &c. is governed by the rope, and ta- 

 per at the ends to three-eighths of the breadth of the 

 middle; the pins at each end serving as a vertical 

 axis, is two-thirds of the size of the end. The thick- 

 ness is five-eighths of the breadth. These blocks 

 may be turned in a lathe, and flattened afterward* 

 with a spoke sheave. 



Rack blocks, are a range of small single blocks, 

 made from one solid, by the same proportions as 

 single blocks, with ends in form of a dove's tail for 

 the lashing by which they are fastened athwart the 

 bowsprit, to lead in the running ropes : they are sel- 

 dom used. 



Shoe blocks, are two single blocks, cut in a solid 

 piece, transversely to each other ; they serve for legs 

 and falls of the bunt-lines, but are seldom used. 



Shoulder block, is a large single block, left nearly 

 square at the upper end of the block, and cut sloping 

 in the direction of the sheave. Shoulder blocks are 

 used on the lower yard arms, to lead in the topsail 

 sheets ; and on topsail yards, to lead in the top- 



fallant sheets, and by means of the shoulder are 

 ept upright, and prevent the sheets from jambisg 



