Page 541 - The Ashley Book of Knots

THE ASHLEY BOOK OF KNOTS

3259. Smeaton's blocks. A tenfold purchase. I once saw a drawing'

of this with the name attached and that is all I know about it. The
I ,

, 0 ) larger the number of' shivs, the less efficient is the block. If the nau-

\ , tical rule of subtraction, for loss by friction, is applied, by the time

, I

the becket is reached, at the higher figure of eight per cent per shiv,

" .... .1

a hundred and sixty per cent of the power will have been ex ended,

which is excessive, and if we apply the lower figure of ve per
()

cent per shiv, exactly one hundred per cent has gone. That is to say,

there might not be enough power left when the standing part is

reached to take up the slack. It would, moreover, take twenty min-

utes to move a load that, with a whi ,could be moved in one minute.

If, however, the shivs have ball earings (which they probably

o have) and steel rope is used (which is undoubtedly what was

planned), the figures would be quite different .

•
3260. By the method here shown, tackles may be rove with the

o two blocks in the same plane and with the fall invariably leading to

• a central shiv. Axel S. Blomgren, in his Seanumship (Stockholm,

1923), shows ~3262. I have not seen the method published else-

where. I have tried out ~ 326 I with a farm tackle and found it satis-

factory.

3260. Double purchase.

3261. Winding tackle (equivalent).

3262. Threefold purchase.

32.61

3263. Four-by-three shiv tackle.

3264. Fourfold purchase.

3265. Five-by-four shiv tackle.

3266. Fivefold purchase.

3 '2.6

3267. Mousing a hook. If any considerable load is to be put on a

block, the hook should be moused. A length of marline is doubled

and a BALE SLING HITCH put over the bill which is slipped to the

back of the hook. A number of turns are taken around the back and

bill, the ends being led in opposite circuits. Cross the ends while

263 there is still material and put on tight frapping turns in both direc-

tions from the center. Then add riding turns back to the center and

finish off with a REEF KNOT. This serves the double purpose of'

strengthening the hook and preventing the hook from spilling.

3268. The names of the different parts of a hook are noted in the

diagram opposite.

3269. A mousing of five or six turns of marline. Cross the ends at

the middle and, using both ends, add frapping turns to the end of

32.66

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