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As
you schedule your annual maintenance check on
your boat, please be sure to include rigging inspection
on your list. Many times, rigging inspection is
overlooked. But the right rigging is essential
to boating safety and performance.
Whether or not you have Navtec rigging on your
boat, following are some helpful pieces of information
on what to look for when inspecting your rigging.
With a global distribution and service systems
that answers the demands of all its customers,
Navtec is easy to reach no matter where you are
sailing. Contact
Navtec for information on our rigging and
hydraulic systems, answers
to technical questions and for a full list
of our authorized distributors
and service providers.
What should I look for when inspecting my rigging?
Cracks in rigging components, especially cracks
that are orientated transverse to the load are
a sign of impending failure. Cracks can be found
using visual inspection, a magnifier, or by dye
penetrate testing. X-ray testing, eddy current
testing, ultrasonic testing and other professional
methods can be used.
For visual inspection, the rod or fittings must
be cleaned or polished to expose the cracks. Rusty
areas frequently indicate cracks underneath. In
addition to cracks, you should look for corrosion,
pitting and rust. Any areas showing discoloration
or potential corrosion should be thoroughly cleaned
and inspected. If any evidence of corrosion remains
after this cleaning, please consult an authorized
Navtec rigger. Pitting and/or corrosion could
require reheading or replacement of the rod or
replacement of the fitting.
Alignment of the rod and fittings to the load
is very important to give good life of rod (or
wire or other) rigging. Misalignment of fittings,
caused by interference or bends in the rod, should
be checked. Kinks or bends in the rod result in
increased local stress and dramatically reduce
the life of the rod. If a fitting or rod has operated
in a bent, kinked or misaligned condition, it
should be replaced, as the damage due to cycling
cannot be undone. If a rod is bent and then straightened
before it is used again, depending on the severity
of the bend, it will frequently provide normal
life. This is a judgment call and the Navtec Engineering
Department should be consulted. Depending on the
size and use of the yacht it is frequently wise
to have the rig inspected by a professional annually.
Navtec recommends.
The question of how long does a Navtec rod rigging
system lasts is not an easy one to answer because
there are many variables that can come into play.
The major factors to consider are:
What loads are put on each of the pieces of rod
in comparison to each piece of rod's breaking
strength?
The sailing conditions in which that the boat
has predominantly sailed.
The amount of care and maintenance that has been
given to the rigging.
The amount of time and/or miles the boat has been
in service .
The severity of the marine environment the particular
boat has experienced (fresh vs. salt and temperate
vs. tropical).
The sizes of the shrouds and stays used on each
boat are picked by either the yacht designer,
the mast builder or possibly by the rigger who
installed and headed it. A racing boat tends to
use relatively smaller rod sizes to keep the weight
and windage down, which will shorten the rod's
life since the maximum normal sailing loads may
approach 50% of the breaking strength of the rod.
A cruising boat tends to have a higher safety
factor when the rod sizes are chosen so that the
loads would only be 15-25% of the breaking strength
at maximum normal sailing conditions. Another
factor that makes any prediction of rigging life
harder is the fact that rigging costs invariably
come into play when sizing choices are made. Smaller
rod sizes for a given application yield shorter
rod life, as the safety factors involved are reduced.
If the boat has been predominantly sailed in heavy
air conditions, the life of the rod will be shorter
than if the boat was sailed in lighter wind conditions
or sailed very infrequently. The higher the rigging
is stressed on a regular basis, the shorter its
life span will be. An analogy: a car's engine
won't last as long if it is continually revved
up to the red line.
If the rigging has been periodically checked,
the end fittings have been rinsed with fresh water,
and general care and maintenance have been employed,
it will last longer. For example, a turnbuckle
can build up corrosion so that it won't turn,
or a spreader bend if left covered in leather
or tape can eventually corrode the spreader or
the spreader bend. Basic maintenance can go a
long way in extending the rigging's life.
The miles the boat has sailed and type of marine
climate are also factors in predicting the remaining
life of the rigging. It has been observed that
corrosion rates are significantly higher in tropical
climates; and with use, any rigging will eventually
deteriorate and wear out.
With all the factors listed above, it is clear
that there are many variables that must be considered
to determine the life of the rod. As a general
rule, Navtec uses a figure of 40,000 sailing miles
as a time when a thorough inspection should be
done. This would include inspection of all the
rod heads and end fittings. If any of the heads
are cracked or worn, the rod should at least be
reheaded. That doesn't mean that the rod itself
would need to be replaced; that would depend on
whether the turnbuckles had enough stroke to compensate
for a shorter piece of rod. In a good installation,
the rod will typically last significantly longer
than the heads on the end of the rod.
After a thorough inspection with no problems found,
depending on the installation, it may be reasonable
to expect the rod to last another 40,000 miles.
However, prudence would dictate what should be
done. If the boat is going to be used for just
local day sailing, you could make frequent inspections
and perform repairs as soon as they were needed.
But if the boat is going to do a long ocean passage
or an extended cruise, it would be smarter to
rehead or replace the rod prior to departure.
One item that Navtec does recommend replacing
after 10 years of use or 40,000 miles (whichever
comes first) is the turnbuckle screws. With the
stress concentrations due to the threads, cracks
could be forming that may not be noticed until
they fail. The screws may last for many additional
years, but it is much cheaper to replace a few
rigging screws than to replace a mast and all
of the rigging.Contact Navtec for further information.
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