Page 540 - The Ashley Book of Knots

PRACTICAL j\!lARLINGSPIKE SEAIHANSHIP

were not widely known in 1893. The earliest record I have found of

the method on 'page 531 is in Axel S. Blomgren's SCtWumsbip (Stock-

.~oltll, 11)23)' tic gives the threefold purchase. Knight, in 1908, gives

a threefold purchase by the method on page 532.

3251-57. With a three-shiv, or larger, block much is gained by

having the fall lead to the center shiv. If led to an end shiv, the block 325"'

will cant, so that the fall will chafe against the shell. The tackles 325"2

dr-scribed on this page are sometimes termed "right-angle tackles."

Numbers 3251 and 3253 are the only ones I have ever seen described

or in use, but in case someone should have occasion to employ some-

thing else I have rounded out the series up to five shivs. The propor-

tions of the blocks are exaggerated and the details eliminated to make

the lead of the fall clearer to the eye. The shivs are numbered with-

out being drawn. So if the falls are rove in rotation as numbered,

the working end will always lead to the center shiv (which is most

lesirable). The general rule is to reeve at the fall block from the

center outward and at the lower block to reeve from the outside

inward. The cycle in each case is from the innermost shiv to an

i
outermost shiv' to the innermost remaining shiv, to the outermost

remaining shiv, etc.

3258. This fivefold purchase presents a variation from the rule

just given. The working end is led each time to the innermost vacant

;hiv until all are full. This might prove the more practical way, but

on paper an adherence to the rule given above promises better.

For very heavy lifts, hooks on blocks are seldom used. Double

eye straps are preferable, and these may be either lashed or toggled.

3251. Luff tackle (equivalent).

3252. Double purchase.

3253. Winding tackle (equivalent).

3254. Threefold or triple purchase.

3255. Four-by-three shiv tackle. '32.SS

3256. Fourfold purchase.
32.S6

3257. Five-by-four shiv tackle .

•

3258. Fivefold purchase.

325"

32.58

I 53 1 ]