FAQ: Rig Tension
How much tension should I put on the Rig?
"Setting up your mast"
your comments, questions, and suggestions. He has raced and cruised boats
from Interclubs to C&C 39s.
Quotes from AOL Sailing Forum Leader, Bill Hamm, who recently
suggested: "Unless you are racing, use care in over tensioning the
rig. Unless you're looking for the last iota of speed, a somewhat loose
rig is easier on the equipment. Just snug is usually just fine."
In the Sailing Forum we get many questions about keeping the shrouds
tight enough to prevent the leeward shroud from going slack when on a
tack. Not a good idea. Most boats today are plastic. Given enough shroud
tension for long enough, you will find that eventually you will be able to
slide into that narrow slip with ease. And if you pay for your dock by the
foot, you may qualify for a lower fee if you habitually keep maximum
tension on your backstay<g>. Not a good idea.
In last week's column I noted that Nigel Calder suggests 15% of
breaking strength for upper shrouds, 20% for the backstay, and something
less than 15% for the lower and intermediate shrouds, as these are shorter
than the cap or upper shrouds. As you beat to weather your leeward shrouds
will go slack. That's fine. Don't worry about it.
Before setting tensions, you need to position the masthead. I like to
use a steel tape. Make sure the lower shrouds are slack. Shackle the tape
end to the main halyard and run it to the masthead and cleat the halyard.
Be careful not to jam the shackle into the masthead. Applying a
comfortable tension, measure to one of the upper chainplates. Now go to
the other side of the boat and see if, with the same tension applied, you
get the same measurement to the top of the chainplate. If not, adjust your
uppers accordingly, until you get fairly equal readings. Now measure to
the backstay chainplate and record the result. This gives you a reference
if you later want to correct a bad helm, or to simply duplicate this
setting next season. If you don't have a better idea, I would start with
about six inches of aft rake in the mast. Measure this at the mast step by
hanging a wrench from the main halyard.
Now, using a Loos Gauge, adjust the uppers and then the backstay to
Calder's suggested tensions. Measure to the shroud chainplates again. Did
anything change? If so, re-center the masthead and adjust your tensions.
Now tension the lowers. Then sight up the mast track, to see if the mast
is straight. If not, adjust the lower and intermediate shrouds until the
mast is straight.
You will want to check the mast while under sail to see if it is still
straight. As the wind increases some forward bow in the middle of the mast
is usually good, as it will help to flatten the main. If you are racing
you will want to make adjustments based on the expected winds for each
Wait! We didn't check the forestay tension. Nope. Forestay tension is
generally determined by the tension on the backstay. Many modern boats
have some way to easily and quickly adjust the backstay, adding tension as
the wind increases. Don't forget to ease that backstay on runs and once
back at the dock.
For a simpler measure of rig tension, just walk around your club or
marina and test the shroud tensions on other boats of similar size and
style to yours. Be sure to check more than one. How do you know that the
first boat you check is correct? Maybe he's the club champion. That might
be a good place to start.
Important: The opinions expressed here are those
of the individual contributors to this page, and not those of the Catalina
34 National Association or Catalina Yachts, Inc. Additionally, this
material has not been reviewed by Catalina Yachts, Inc. for technical
accuracy. This page's maintainer cannot guarantee the accuracy of this
information or the desirability of suggested modifications or upgrades.
Please obtain assistance from a competent marine mechanic or boatyard
prior to making any significant modifications to your vessel.