B L O 



(hoe-block, the niouldcr-block, the fider-block, the fnatch- 

 'bloc-k, the ftrap-bound-block, the viol-block, and the warp- 

 ing-biock. The prmcipal parts of blocks are their (he)ls, 

 fhcavcs, and pins, which are of various Irzes and powers, ac- 

 cording to the effect which they are to pruducL". The di- 

 ir.enfions of the (hells, and the thickncfs and number of th.e 

 /heaves, are proportioned to the fize of the ropes working in 

 them, and the powers required. The (heaves turn abreaftof 

 cacli other in the (liell, on one axis or pin, or one above an- 

 other, on fcparate pins. Tlic (hell is made of elm or adi, and 

 hollowed between the cheeks, with one or more (lieave-holes 

 to receive the (heave or (heaves. On the ontfide of the 

 checks of blocks that are to be (trapped, one fcore is cut 

 towards tlie ends, in which part of the drap is buried ; 

 if they are double -ftrapped, they have two fcores. A 

 hole is bored through the centre to admit the pin ; which, 

 pafling through both (uicsof the (hell, forms the axis for the 

 (lieavcs. The (heave is a folid cylindrical wheel, and round 

 its circumference is a groove, one-third of the thicknefs of 

 the {lieave deep, in which the rope works. It is commonly 

 made of lignum vits ; but for laborious purpofes, it is coaked 

 }n the middle with metal, or elfe made of caft metal ; if the 

 flieave is iron, it is coaked with brafs, and if of brafs, w ith the 

 hardeft bell-metal. The hole in the centre is foinewhat larger 

 than the pin. The [nn is made of lignum vitx, cocus, green- 

 heart, which is a wood imported from the Welt Indies, or 

 iron, and it is the axis on which the (lieaves turn. 



The proportions for linglc, double, treble, fourfold blocks 

 are as follow ; viz. the length is eight times the breadth of 

 the fheayc-hole, which is one-fixteenth of au inch more than 

 the thicknefs of the flieave ; and this is one-tenth more than 

 the diameter of the rope for which it is intended, and the dia* 

 meter of the (heave is five times the thicknefs. The breadth 

 of the block is fix times the thicknefs of the (heave, and the 

 thicknefs about one half the length. Flat thin blocks are 

 three-eighths of the length thick ; but all blocks, having 

 more than one (heave, arc increafed in thicknefs more than 

 in the above proportion by the additional number of (lieave- 

 holes, and middle-parts or partitions ; the thicknefs of each 

 partition being one-fixth lefs than the breadth of the (lieave- 

 hole. Thefe dimenfions are variable, according to the ufes 

 for which blocks are intended. Very large and four-fold 

 blocks are formed of feparate pieces, as the cheeks, partitions, 

 &c. ; and when thus made, they are denominated " made- 

 blocks." The (hells of blocks are firft fawed to their length, 

 breadth, and thicknefs; and the corners or angles are taken 

 o(F. The workman then gauges the fize of the (heave-hole 

 in the middle, one fixteenth larger than the thicknefs of the 

 flieave, and once the thicknefs longer than the diameter, for a 

 fingle-lheaved block. In blocks of two (heaves, the partition 

 is kept in the middle, and is one-fixth lefs than the ilieave- 

 hole ; each fheave-hole is gauged equally on each fide, and 

 fo for all blocks with a greater number of (lieaves. The 

 blocks are then jambed up edgeways with wedges in a clave, 

 and the (lieave-holes are made in this manner : the length and 

 breadth are firll gouged out, and holes are bored half way 

 tlirough the block, along the part gouged out, with an augre 

 of the fize of the (heave-hole ; then the fheave-hole is gouged 

 and bored on the oppofite fide in the fame manner, fo as to 

 meet the oppofite holes. Blocks from lo incius and up- 

 wards have one hole bored at each end, and cut through with 

 a chiffel ; and the wood is fawed out with a rib-faw. All 

 blocks have the (heave-holes cleared through by chiflfels, and 

 by burrs at the corners. Blocks that are lo have iron ftraps, 

 fliould have the ftrap fitted on before the wood is cut out of 

 the middle. The hole for the pin is bored through the mid- 

 dle of the block, one-tenth lefs than the diameter of the pin. 

 The outfidcs and edges of the (hell arc iipxt rounded oft by 

 8 



B L O 



the (lock-rnave, and neatly finil-ed by the fpokc-fhave. In 

 the royal navy, blocks are left thick upon the edges of the 

 cheeks; but in the nit rchant- (hips, the edges are fometimee 

 thinned off to a fmall fquare, and fometimes rounded off. 

 The fcores for the (traps are gouged out along the oulfdes 

 of the cheeks, and tapcrin depth from noth'iigal the pin to 

 half the thicknefs of the flrap at the ends of the block, for a 

 fingle fcore, and the fame on each fide of the pin for a double 

 fcore. The fcores are gouged down, acrofs the breait of 

 the block, to half the fize of the (^rap, in order to allow for 

 the fcrving. After the fcore is cut, the (heaves are fitted ; 

 they are one-tenth thicker than the diameter of the rope in- 

 tended for rniining on them, and five t:mes that thieknels in 

 diameter. The hole for the pin fiionld be bored through the 

 centre by a bitt fixed in the mandrel of a turning lathe, or 

 with a (lock and bitt, and rea'iied with an augre one fix- 

 teenth larger than the di;imeter of the pin, that it may eafily 

 turn ; they are then put in a lathe and turned fmooth, and 

 the outer circumference hollowtd one-third of its thicknefs, 

 that the rope may embuice it clofely. The diameter of the 

 pin is the thicknefs of the (licave, and is turned in a lathe, ex- 

 cept its head, which is left eight fquare, to prevent its turn- 

 ing in the block, and is driven throngh the holts in the block 

 and (heaves. After the (heaves are fitted, the infide of the 

 flieave hole, at the arfe of the block, is gouged hollow, to ad- 

 mit the rope, and correfpond with the flieave ; and a fmull 

 neat chamfer is taken oft the edges. 



Blocks, Bee, are made of elm, in length feven-ninths 

 the length of the bee, in depth two inches tor every foot of 

 length, and in th.ickuefs feven-eighths of the depth. A 

 block of this kind is trimmed Iquare, chamfered on the out- 

 fide edges, and fitted with a fheave in one end ; and in the 

 other end is cut a hole, to be fitted with a fheave, in cafe 

 the other iliould fail. The (heave-hoIc is -^ths of the length of 

 the block, and ^Jtli the length of the (heave-hole in breadth, 

 and half the length of the fheave-hole within the end. Bee- 

 blocks are bolted to the outer ends of bowfprits, under the 

 bees, and the bolts ferve like the axis or pin for the (lieavcs 

 to work upon ; the fore-top-ma(t ftay reeves through the 

 fheave-hole at the fore-ma(t end of the ftarboard bee-block, 

 and the forc-top-maft preventer, or fpring-ftay, through the 

 (heave -hole at the after-end of the lai board bee-block. 



Blocks, Brail, in rigging the mizen-yard, are ftrapt 

 together in one ftrap, and lie over the yard, and ftize toge- 

 ther underneath ; the throat-blocks next the cleats to the 

 ma(t; the middle-blocks in the middle between the throat- 

 block and peek ; the peek-blocks about three or four feet 

 within the cleats at the peek. 



Blocks, Bunt-l'ine, are lafhed in rigging the lower-yarns 

 hke the leech-lir.e blocks in the middle bet.veen them and the 

 flings of the yard. Thefe, in rigging the top-fail yards, 

 are fpliced round the (trap of the top-fail-tye-block upon the 

 yard. 



Block, Cat, is employed to draw the anchor up at the 

 cat-head. See Cat-heads. 



Blocks, C/jcr/J, or half-blocks, are made of elm-plank; the 

 length being twice and a half the depth of the top-mail head ; 

 the breadth is feven-eighths of the depth of the top maft 

 head, and the thicknefs half that depth. The depth of each, 

 tenon, and thicknefs of the cheek, when the flicave-holc is 

 c'.;t, is each three-eighths of the whole thicknefs, fo that 

 the remaining two-eighths are the (heave-hole. The three 

 tenons are each two inches fquare, one in the middle, a:id, 

 one at each end ; and ti:e length of the holes is more than 

 the breadth of the block, by the thicknefs of the flieave. 

 The back of the block is divided into three parts, and one- 

 third on each fide is bearded down to one-third the thick- 

 nefs of the cheek ou each edge. Pins of iron arc made for 



fallen- 



I 



