Page 310 - The Complete Rigger’s Apprentice

But checking and shifting do not lessen chafe.
To do that, you need to analyze what is causing it
in the first place, and act accordingly. If you have
good-quality rope clutches, for example, chafe
should not be a serious problem unless the rope
size is small compared with the loads exerted on it.
Likewise, chafed-through rope or wire strands on
a halyard can be caused by a too-small sheave (see
“Blocks,” in Chapter 2), and mainsail chafe can
be caused by the cloth bearing on an after lower
shroud. In the latter case, it’s not practicable to
increase the wire size, so instead pad it with service,
leathering, or baggywrinkle, or have a chafe patch
sewn onto the sail.
Chafe can also be caused by things being where Figure 7-27. A strut on a Dorade vent alleviates head-
they don’t belong. Staysail sheets delight in bearing sail sheet snags.
on stanchions, shrouds, and anything else between
clew and winch. But a little thought and intelligent
use of turning blocks will eliminate this problem. leaving room for a halyard to wedge itself between
the sheave and the mortise wall.
Snags Rule 3 leads us out of the relatively simple
world of fastenings and friction and into the subtler Corrosion Corrosion is always a problem in a
realm of ballistics. An unsecured running backstay, saltwater environment, particularly when you mix
for example, will chafe as it flops around, but is antagonistic materials such as aluminum and stain-
liable to cause even more problems by grabbing at less or stainless and carbon fiber; these materials are
stanchions, turning blocks, gear lashed to cabintops, on different points on the galvanic scale, and when
and you. Surveys are opportunities to take action to joined by the conductive medium of water they set
prevent snags. up an electrical current. The resulting activity cor-
Most often, it is jibsheets that snag, and usually rodes whichever of the two materials is least noble
in mid-tack. When doing a survey, flop the sheets (lower on the galvanic scale). While not as serious
around intentionally to see how close they come to with rigging as with permanently immersed items
snaggable cleats, vents, spinnaker poles, bitts, etc. If such as hull fastenings, galvanic corrosion can over
a snag seems likely, modify or relocate the potential time weaken spars, and clog such machinery as
snagger. A simple strut added to a Dorade vent, for winches and blocks.
instance, can prevent an inadvertent vent launching The first thing to do is to take note of places
(Figure 7-27). where dissimilar materials are in contact. Then go
More than running rigging can be slack. If about isolating them with some form of noncon-
you’ve attached antenna wire to a shroud with those ductive bedding. This can be as low-tech as parcel-
little electrical ties, watch out for their degrading ing and serving to isolate galvanized steel wire from
in sunlight. When they let go, the wiring will start bronze thimbles, or it may involve Tef-Gel, Eck, or
waving around, eager to catch the odd line or sail. other compounds to isolate aluminum or stainless
Likewise, the tape that secures spreader boots can fasteners (see sidebar “Favorite Goops,” page 224).
come undone, exposing a little opening in the boot When surveying an aluminum spar, pull a few fasten-
that halyards just love to crawl into. Worst of all are ers and examine the screws and the holes they came
masthead sheaves that are slack in their mortises, from. If you see a white powdery substance on either,

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