Inspect Your Standing Rigging
When was the last time you really inspected your boat’s
standing rigging? The mast, stays,
shrouds, spreaders, et al??? If you are
like most sailors, it’s probably been a while.
So, here’s a few thoughts:
Spreaders – I see quite a few boats where the spreaders (which
give mechanical advantage to the upper shrouds) are set up at the wrong angle
to the shroud. To work properly, the
spreader should “feel” compression only.
The way to make sure that your spreaders are in compression is to make
sure that the spreaders bisect the angle that the upper shroud makes as it goes
from deck to high up on the mast. If the
upper shroud’s angle at the spreader tip is 160 degrees, the angle on each side
of the spreader (above and below the spreader) should be 80 degrees on both
sides. If there is a difference between
the angle below the spreader and the angle above the spreader, the spreader
experiences compression on one side and extension on the other side. The spreader is trying to bend. If your boat experiences a sudden gust of
wind or pounds down hard off of a wave, the difference between the compression
half and the extension half of the spreader can cause the spreader to break. This almost always ends up with a catastrophic
mast failure and the boat slowing down suddenly. Next time you are at the boat, inspect the
angles on the upper shrouds at the spreader tips.
Elongated Holes in Tangs and Chain Plates – Over the years,
your mast and the standing rigging move.
Loose rigs move more than tight rigs… but, all rigs move. The movement causes friction and wear in the
fittings. Most stays and shrouds are
secured to the mast tangs and to the deck chain plates with clevis pins which
(when the boat is new) fit snuggly into holes in the tangs and chain plates
(and the associated forks, eyes and toggles).
Over the years, the mast and rig movement “work” these fittings and
ultimately the holes become elongated.
The elongated holes represent less material in the fitting – making the
fitting become weaker and weaker as time goes along. When you inspect your standing rigging, make
sure that you loosen each shroud and stay (separately) by taking the clevis pin
out of each terminal (top and bottom of the shroud and/or stay) and look
carefully at the holes. If the holes
appear to be oval, or in any way not round, the fitting is suspect and should
be replaced. Of course, it should go
without saying that the proper size of clevis pin should always be used. Don’t put a 3/16” clevis pin in a quarter
inch hole.
Clevis Pins – Just like with the holes in the shroud and stay
fittings, the clevis pins can also wear.
If the clevis pin is not round, it should be replaced. I remember inspecting the halyard sheaves in
a mast cap on a sailboat once. There
were two quarter inch clevis pins about three inches long which acted as the
axels for the halyard sheaves. The boat
owner was replacing the old plastic sheaves which were deteriorating with
bronze sheaves that had been made at a machine shop. Pulling the clevis pins out of the mast cap
was a bit difficult because – over the years – the loading from the halyards
had bent both clevis pins quite a bit.
To get the pins out, we had to use a drift punch and hammer.
Cotter Pins – The clevis pins are generally secured to fitting
by using either a split ring or a cotter pin.
If your boat has cotter pins, they should be cut just a little longer
than the diameter of the clevis pin.
Then, the cotter pin should be bent open equally to an angel of about
ten degrees for each side. Doing this
makes removal of the cotter pin in the future go much more easily.
Shrouds and Stays – These days most sailboats have stainless
steel wire rope for the shrouds and stays.
When you inspect the standing rig, take a paper towel and “run” the
towel up and down each shroud and stay.
If one of the little wires that make up the shroud or stay has broken,
the broken end (sometimes called a meat hook) will snag the towel instead of
your hand. Any shroud or stay with a
broken wire, the shroud or stay should be immediately replaced.
Turnbuckles and Swaged Fittings – Most sailboats use swaged
fittings at the ends of the shrouds and stays.
The swaged fitting is held to the wire with compression. The fitting might be a fork, an eye, or a
threaded bolt. If you live in a part of
the country where there is a real winter season, water from snow and rain can
get in between the wire rope and the fitting.
When this water freezes, the fitting can crack. Of course, the wire rope is no longer held
securely. At the very least, the fitting
needs to be replaced. Many of us will
replace the whole shroud or stay. When
you are inspecting the fittings, also take a close look at all of the
turnbuckles. “Open” turnbuckles are easier
to inspect than “barrel” style turnbuckles.
Look for cracks and corrosion.
One other type of corrosion that can occur on turnbuckles is galling
between the threads on the bolts and the turnbuckle itself. This galling often makes it impossible to increase
or decrease the load on the rig. Simply
turning the turnbuckle one or two turns in each direction will show whether the
fitting has galling. If so, clean the
turnbuckle and bolts thoroughly and lubricate the threads with an anti-seize
lube when you reassemble the turnbuckle.
Don’t forget to “lock” the turnbuckle when the rig is tuned by securing
a wire through the bolt ends to prevent the turnbuckle from “backing out”.
It is probably best to carefully inspect your standing rig
annually as part of your normal maintenance schedule. If your standing rig has not been thoroughly
inspected for several years (or you don’t know if it ever has been inspected),
the time for the inspection is NOW!!!!
Don’t delay. Remember, if your
mast falls down, you will be the “talk of the dock” for years……
