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in ttie'direftion of the fheave. Shoulder-blocks are ufeJ on 

 the lower yard-arms, to lead in the tnpfaiUfhcets ; and, on 

 the topfaii-yard';, to lead in the topgallant-flieets ; and by 

 means of the (lionlder, are kept upright, and prevent the 

 flicets from jamhiiig between the block ai:d the yard : they 

 arc alfo ufed at the outer end of the boomkins, to lead in 

 the fore-tacks. 



Blocks, Slfiti; arc made of nfli, fimilar to two fmgle 

 blocks, and are turned out of a folid piece, about twenty 

 inches long, one above the other ; between the blocks is a 

 feorc for a middle feizing : a round head is turned at each 

 end, and hollowed underneath, to contain the cnd-leizings ; 

 along the fides, through which the pins are driven, is a 

 groove, large enough to receive part of the topmaft-fliroud, 

 in which it is fci/.ed. In thefe blucks reeve the lifts, and 

 reef-tackle-pendents, of the topfail-y; rds. 



Blocks, S/.ti-Zi/ie, in rigging the lower-yards, are ftrapt 

 with a fliort lafliing-eye, that feizes to the fpan of the quar- 

 ter-blocks underneath the yard. 



Blocks, Snaic/), are proportioned by the rope, as a fm- 

 gle block, leaving twice the length for the fcore and lafliing ; 

 they taper from the fheave to the lafliing end, to half the 

 breadth and tliickuefs at the flieave ; one fide of the (hell is 

 cut acrofs above the fheave, large enough to admit the rope 

 or fall. In the Rnyal Navy, fnatch-blocks are iron-bound, 

 terminating at the fmall end with a fwivelhook, or an eye, 

 large enough to receive feveral turns of lafhing ; that part 

 of the flrap, over the notch in the fide, hfts up with a 

 hinge, and is confined down, when the rope is in the block, 

 by a fmall iron hook, or latch, that hooks in the eye of a 

 toggle-bolt, and that fecures the upper end of the ftrap ; 

 the hinged part of the llrap goes over the bolt, with a hule 

 in the end ; the llrap is let into the block its thicknefs, and 

 is confined by the pin and nails ; they are ufed for heavy 

 purchafes, and where a warp, or hawfer, is brought to 

 the capllern. Snatch-blocks, not iron-bound, have a 

 large hole bored through the tapering end of the (hell, for 

 the lafhing. They ace ufed for the main and fore fliect 

 blocks of fquare-rigged veffels. 



Block, Spring, a new kind of block, invented by Fran- 

 cis Hopkinfon, efq. of Philadelphia, and defigned to alTill a 

 vtffel in faihng, by increafing the afting fpring of her rig- 

 ging. It is propofed to apply it to all fuch parts of the 

 '''gg'"g.a5 will admit of it with fafety and convenience, and 

 where its operation will be moft advantageous ; but parti- 

 cularly to the (heet ropes, and, if practicable, to the dead- 

 eyes, in lieu of what are called the chains. A (fee Pla/e of 

 Ship) is a block made in the ufual manner, having a ring, 

 or eye, B, at one end. C, is a fpiral fpring, linked at one 

 end to the hook DE, and at the other to the ring F, which 

 is to be annexed by a ftaple to the timber-head, or by fome 

 other means to the place where it is to be applied. The 

 fpring C mud be of well-tempered fteel, and proportioned 

 in llrength to the fervice it is to perform. Within the ca- 

 vity or pipe, formed by the fpiral fpring, there mud be a 

 chain of fuitable ftrength, called a check-chain (reprefented 

 feparate at G), connedcd by the hnks to the hook DE 

 and ring F. W.hcn tlie fpring is not in aftion, this chain is 

 flack ; but when the fpiral fpring is extended, by the force 

 of the wind, as far as it can be without danger of injury, 

 the check-chain muft then begin to bear, to prevent its 

 farther extenfion, and, if Ilrong enough, will be an etfedual 

 fecurity againft failure. 



Fig. 2. reprcfents part of the gun-wale of a (loop, with 

 the fpring-blocks in aftion, one of them hooked to a ftnple 

 in the timber-head, and the other to the corner of the jib. 



The inventor of this machine apprehends, that a vcffcl 

 thus fmuifhed will be lefs liable to heel ; and that (he will 



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receive the impulfes of the wind to Letter advantage, and 

 fail with a more lively and equable motion than if rigged in 

 the common away. Tranfaftions of the American Philo- 

 fophical Society, vol. III. art. 40. 



Blocks, S/rnp-iounJ, are fingle blocks, with a flioulder 

 left on each fide, at the upper part, to admit the (trap 

 through, a little above the pin. Thefe blocks are ufed at 

 the clues of the fquare-fails, for the clue-garnets or clue- 

 lines, and under the yards ; the fliouider prtl'erves the ftrap 

 from chafing. 



Block, Thicl ar.d thin, or Qunrlcr, is a double block, 

 with one (heave thicker than the other, and is ufed to lead 

 down the topfail-flieets and clue-lines. In the merchant 

 fervice they are ufed fuigle, thick and thin. In rigging the 

 lower yards, they are 111 apt with a long and (liort leg, with 

 a lalhing eye fpliced in the ends, and lafli to the yard within 

 the cleats, in the middle of the yard, the block hanging 

 downwards. The long leg comes up the aft-fide, and 

 meets the Ihort leg on tlie fore-fide, and there lafhes through 

 the eyes. Although thefe are ufed for the topfail-lheets, 

 and intended for the clue-lines, a fingle block would be 

 cheaper and better ; as the thin (heave is feldom ufed for 

 the clue-line, it being found rather to impede than to faci- 

 litate. Small (hips, in the merchant fervice, have a double 

 block lafhcd in the middle of the yard, as the quarter-block, 

 through which the fheets reeve, and lead down on oppofite 

 fides. Large fliips, in the merchant fervice, have a fingle 

 block ladled on each fide of the middle of the yard, and the 

 (heets reeve on their refpetlive fides, and lead down by the 

 mad. A quaiter-block, in rigging the crofsjack-yard, is 

 ftrapt with a double ftrap, with an eye in each of the four 

 ends, and is lalhed upon the yard in the middle between the 

 cleats. 



Block, Top. See Top-Rope, 



Blocks, Top-Gallant-Sheet, in rigging topfail yards, are 

 ftrapt with two lafhing-eyes, and lafh upon the yard, clofe 

 within the cluc-line-blocks on each fide. 



Blocks, Topfail-Shect, in rigging the lower yards, arc 

 put over the yard-arms, ftrapt with an eye of the ftze of the 

 yard-arm. 



Blocks, Tricing, for the yard-tackles, are ftrapped with 

 a fhort la(hir.g-eye, that feizes round the yard about one 

 third of the length within the arm-cleats; the blocks hanging 

 under the yard. 



Blocks, Tye, in rigging the topfail-yards, Ia(h at the 

 topmad-head clofe up to the rigging, under the collar of 

 the day, as the lower ones ; and the blocks on the yards 

 ladi under the fore-part of the yard, as the lower ones, and 

 reeve with a double tye, in large diips, and with a fingle 

 tye, like the lower, in fmall ones. The ftanding-parts of 

 the double tyes clinch round the maft-head, t'hen reeve 

 through the double block upon the yard, and up again, and 

 reeve through the block on each fide of the mad-head. 

 The blocks are then fpliced in their lower ends, and 

 connefted by their haiiards to a fingle block, that is ftrapt 

 with a long ftrap, with a hock antl thimble, that hooks 

 to a fwivcl-eye-boh in the channel on each fide ; the leading- 

 part comes in through a block laflied -on each fide ; the 

 forcmoft ones abaft the forecallle, and the after ones on the 

 quarter-deck. 



Block, Foyol or Viol, is a large fingle-dieaved block; 

 the_ length is ten times the thicknefs of the (heave-hole, 

 which is three-eighths more than the thicknefs of the flreave; 

 the thicknefs of the Iheave is one tenth more than the dia- 

 meter of the viol, and ihe diameter of the fheave is feven 

 times the thicknefs. The breadth of the block lliould be 

 eight times the thicknefs of the dieave, and the thicknefs 

 two-fevenths of the length. This block is double fcored, 



the 



