Page 51 - The Complete Rigger’s Apprentice

blocks can produce from 8 to 28 parts of purchase.
On modern boats, you’ll find compound purchases
on outhauls, vangs, and even on the backstay—
that’s right, we make running rigging part of the
standing rigging.

Right-Angle Reeving
With blocks that have their sheaves mounted side by
side—most often the case—the manner in which the
rope passes from sheave to sheave can make a great
difference in hauling efficiency. Figure 2-10 shows
two double blocks reeved in the usual manner,
called Lacing. The line travels in a spiral from one
side to the other as it passes through the sheaves. Figure 2-10. “Laced” double blocks, in which the line
This method is simple and easy to remember, but proceeds in a spiral course through the sheaves.
when the blocks are hauled close to one another—
“two-blocked”—the rope bears strongly against the when the boat is hoisted. This method requires a
cheeks of the blocks, causing undue friction just little thought at reeving time, but if you’ve ever had
when you need it the least. to lift a heavy load the full range of your tackle and
The alternative is Right-Angle Reeving (Figure felt your power agonizingly diminish as you neared
2-11), sometimes known as Boat-Fall Reeving, the the top, you know that Right-Angle Reeving is
latter name deriving from its frequent appearance worth the effort. Less friction means the rope lasts
on lifeboat davit gear, which is usually two-blocked longer, too.

Figure 2-11. Four examples of Right-Angle Reeving.
The fairer lead throughout means less chafe and lon-
ger rope life. The fall comes from the middle sheave of
three-sheave upper blocks, so that the force of hauling
does not tip the block.

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