[J22-Fleet 1] j22 keel bolts

[Lars Hansen]

   Greetings!

We are going away from our usual somewhat breezy depiction of what's 
going on with Waterline Systems, to bring you some actual, important 
information that everyone should be aware of.

Please read it and pass it along.

It is also available on our website:
http://www.waterlinesystems.com/HowTos/KeelBolts.pdf

Keel Bolt Maintenance Bulletin


There aren't many maintenance areas that are more important, or more 
often overlooked than keel bolts. This is true for every boat, but 
particularly so for J/22s, J/24s and J/80s, all of which routinely hoist 
the boats in and out of the water using the bolts.

Failure of any keel bolt is bad, but most bolts are part of a massively 
redundant system, where the failure of any one bolt is rarely 
immediately catastrophic.  For boats that are hoisted, the failure of a 
bolt holding the lifting gear can be catastrophic and has the potential 
to lead to the loss of the boat, or much, much worse.

While this article is being distributed to USWatercraft and J/Boats 
customers, it applies to virtually all production boats, regardless of 
builder or brand.  If they use Stainless Steel keelboats and most of 
them do, it applies. Feel free to pass it along to your friends and 
fellow boat owners.  It's pretty important.


Since they live in the bilge, keel bolts can fall into the category of 
"out of sight, out of mind". It is because they live in the bilge that 
they need routine care and attention.

J/22 keels are made using 316 Stainless Steel threaded rod, which is 
cast into the lead. The nuts, washers and lifting bar are made using 304 
Stainless and are then electro polished. This has been the industry 
standard for many years, and has provided many years of service life.

Stainless Steel is corrosion resistant, not corrosion proof

The basic resistance of stainless steel occurs because of its ability to 
form a protective coating on the metal surface. This coating is a 
"passive" film, which resists further "oxidation" or rusting. The 
formation of this film is instantaneous in an oxidizing atmosphere such 
as air, water, or other fluids that contain oxygen. Once the layer has 
formed, we say that the metal has become "passivated" and the oxidation 
or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. 
per year).
Unlike aluminum or silver this passive film is invisible in stainless 
steel. It's created when oxygen combines with the chrome in the 
stainless to form chrome oxide, which is more commonly called "ceramic". 
This protective oxide or ceramic coating is common to most corrosion 
resistant materials. Unfortunately Halogen salts, especially chlorides 
easily penetrate this passive film and will allow corrosive attack to occur.

CONCENTRATED CELL OR CREVICE CORROSION

This corrosion is common between nut and bolt surfaces. Salt water 
applications are a severe problem because of the salt water's low PH and 
its high chloride content. Here is the mechanism:
Chlorides pit the passivated stainless steel surface.
The low PH salt water attacks the active layer that is exposed.
The absence of oxygen inhibits the re-forming of the passive layer.
These three factors work together in a vicious cycle, repeatedly 
attacking the same small area.  If the metal is under tensile stress- 
like from an over torqued keel bolt nut, the pit formed can transform 
itself into a crack.  When a crack forms the process repeats and 
accelerates as the surface area of the 'active' layer is now much larger.
Prevention is the best cure


The best way to prevent corrosion is to keep salt away from your bolts.  
The best way to do that is to keep your bilge clean and dry.  We've 
designed our interiors to be easily washed down. Take advantage of 
this.  At the end of the day, when you hose off your deck hardware, 
stick the hose down the companionway and blast out the bilge and bolts. 
Pump and sponge dry and leave the floorboard off when you leave.  Not 
only will this protect your keel bolts from corrosion, it will prevent 
mildew and keep your interior looking and smelling fresh.

Important note! Avoid using any cleaning products containing chlorine.  
Chlorides are just what we are avoiding.  Read the label.  Clorox, 
Comet, and Fantastic are all products that while good for most stuff are 
bad for this application.  Check the label.

Annual Maintenance


Checking your keel bolts should be part of your annual maintenance 
plan.  Working one bolt at a time, remove the nut and washer and clean 
the threads with a small nylon or brass brush or scotch brite.  Do not 
use a steel wire brush, as this can lead to other corrosion issues not 
covered here!  Check for signs of rust.  If everything looks good, use a 
generous coating of anti-galling compound and re-torque the nut. Most 
J/22 keel bolts are 5/8

Keel Bolt Torque Table


Bolt Diameter
Torque Nm
Torque Ft/Lb
1/2"
26.0
19.2
5/8"
66.0
48.7
3/4"
130.0
95.9
7/8"
190.0
140.1
This Table is derived from information in Table A7 from ISO/DIS 
12215-9.2. These values are for well greased threads. Friction in the 
screw and under the bolt head makes up approximately 90% of the 
tightening torque and approximately 10% contributes to prestressing of 
the bolt. The user is cautioned to use good judgment in applying these 
values.


Tip- If you can pull in your mainsheet, you probably don't need a big 
breaker bar to torque your nuts.  Over-torqueing is extremely bad.  
Particularly on the bolts holding your lifting rig, under-torqueing is 
equally bad.  If the nut is loose enough to allow movement in the bar, 
the bolt can be loaded unequally, leading to tension stress on one side 
of the bolt.

While you are there


Since you are spending some time with your bilge anyway, this is a good 
time to give the rest of your lifting gear a good look over.  Check your 
sling for any signs of wear; fraying, cuts, abrasions and the like.  
Your sling should look essentially new.

If you use a shackle in your system, check it too.  If it is bent, 
rusted or shows signs of wear, just replace it.  A new sling costs 
around 50 bucks and a shackle around 9 bucks.  It is the cheapest peace 
of mind available.

If you think you find a problem

If you find or suspect you have problems beyond a good cleanup you 
should contact a marine surveyor who can inspect and report findings. 
Your surveyor will have the specialized knowledge and tools to give you 
an informed recommendation.

Additional Resources

Lots of info on Stainless 
http://www.azom.com/article.aspx?ArticleID=1177#_Background



Recommended Anti-Galling compound

Loctite(R) Marine Grade Anti-Seize  available @ Amazon and a gajillion 
other places
http://www.amazon.com/16-Oz-Marine-Grade-Anti-seize/dp/B0042T5MS0/ref=pd_sbs_indust_4