Page 67 - The Complete Rigger’s Apprentice

Figure 2-29A. The Inclined Plane, another form of
mechanical advantage. In this case, 125 pounds
applied by the truck’s driving wheels can lift the (very
small) 2,000-pound truck.

Figure 2-28. Sweating up. A handy technique to
know, especially, as here, if you’ve lost a winch
handle. Figure 2-29B. The threads of a turnbuckle are simply

a spiral version of an Inclined Plane.
SWEATING UP

This is a remarkably simple, effective way to get a up folks, and watch as a mere puny 125 pounds
little extra tension on a purchase. Hauling sharply picks up a solid ton! Figure 2-29A,B shows that
outward or sideways on an already taut line exerts this feat is accomplished through the miracle of
leverage on the line; if the line is tailed at the belay the Inclined Plane. Once force-resisting friction has
point, the load is forced to shift, giving you a little been reduced to a minimum, it’s easy to shift the ton
slack. Your outward motion must segue smoothly up the slight grade, since only a tiny fraction of its
and quickly into a downward pull, to feed that slack weight is directed against the force. Give me a shal-
to the belay point, where the tailer takes it up (Fig- low enough ramp and I’ll move the world.
ure 2-28). The same principle makes frapping turns Turnbuckles (and bolts and screws) make use
effective; the lever is a versatile tool. of inclined planes that have been bent into a spiral,
thereby packing tremendous mechanical advantage
into a very small space (Figure 2-30). Force can be
TURNBUCKLES applied by hand or compounded with a lever in the
(THE INCLINED PLANE) form of spike or wrench. Since the upper and lower
threads are oppositely pitched, turning the barrel
While we’re talking about means of tightening shortens the turnbuckle, putting tension on the wire.
things, let’s look at the principal means of induc- Because rigs flex and turnbuckles don’t, it is
ing tension in the standing rigging. So, step right extremely important to provide a universal joint in

46