Page 315 - The Complete Rigger’s Apprentice

lanyards before driving the pin out (or see
the accompanying sidebar “Tapped Sheave”). Tapped Sheave
Since you’re probably hanging from the main It’s very tricky to remove and replace masthead
or jib halyard at the moment, you’ll also want sheaves without dropping them—they’re difficult
to switch to an alternate means of suspension or impossible to get a lanyard around. Cruiser
before driving that pin out. The procedure is Steve Dashew has a solution: Drill and tap a small
1
3
( ⁄8 – ⁄16-inch or 3.2–4.8-mm) hole in the bottom
to get your deck crew to haul you up just as of the sheave groove. A hole this small won’t bother
high as the halyards allow. Then tie two short the wire or rope halyard. When the time comes
lengths of stout rope to the chair (or, if you’re for sheave removal, just thread a bolt or machine
screw into the hole. Tie a lanyard to the bolt and
wearing a harness, one to the chair and one to one to the sheave pin, then remove the sheave.
the harness). Secure these lines to the masthead,
hitching around lugs, shackles, or whatever is If you don’t have the proper size clevis
up there. If there are spare halyards, you can replacement, make a note on size and fix it
hitch those to the chair instead. When your on another trip up. If you do have the right
replacements are tight and secure, have the size, you’re faced with the disquieting task of
deck crew slack away on the other halyards. detaching a shroud from a mast you’re sitting at
Detach them from the chair and tie them to any the top of. It is possible to do this, but sufficiently
convenient shroud or stay. Drive the pin out— tricky–and dangerous–that I won’t go into the
constrictoring a lanyard onto it as it comes and procedure here. In general, it is far easier and
pull the sheaves out. Check for wear on the pin, safer to pull the mast than to replace rigging
the sheave bushings, and the mast mortise. If in situ.
they look okay, sand the sides of mortise and
sheaves with fine sandpaper. Reassemble. 5. No toggle on upper end of jibstay.
Check for a fair halyard lead, slop in the No toggle with you or aboard, so make a note
mortise, proper alignment of the pin, and chafe of the size required and of the space between
on the halyard. If there’s more wrong with the the sides of the tang, so you will know if the
sheave or pin than the sanding will fix, you’ll right size toggle will fit. Maybe the space is
need to reassemble and come back up when too small, and that’s why there’s no toggle here
you’ve got a replacement, unless you already now. If so, you’ll have to do something creative,
have one aboard. like modifying the tang. Check with a yacht
designer first.
4. Clevis pin in port upper shroud tang is too
thin or too long. 6. Halyard for roller-furling jib is wire with rope
At some time in the past, someone needed to tail. Rope tail will not fit through wire-only
replace this clevis and didn’t have exactly the sheave. Result is that jib cannot be lowered all
right size. So they went with the nearest thing the way to deck.
they had to a fit. When a clevis pin is too small, Sheesh. Any more like this, and you’ll be
the load from the tang and wire terminal bear at thinking of pulling the stick out so you can work
a single point on the pin. This “point loading” on it more quickly and easily on the ground.
causes weakness, accelerated wear, and fatigue. What happened was that whoever rigged this jib
And of course, a too-small-diameter pin is a weak did so on the ground. They made up a halyard
link. If the pin is too long, it provides that much of the right length, ran the wire end through the
more weight, windage, and cost. It also might jam masthead sheave, then Nicopressed an eye in
into the mast, damaging at least the paint. it for the sail, then shackled the eye to the sail,

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