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Old 08-06-2010, 07:43   #1
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Keel Leek Fix / Keel Bolt Questions

I posted a new thread since this is a slightly different question then one I've posed before. My Chris Craft Apache has a small leak underneath the mast step at the end of the keel/hull joint. The keel is bolted on iron, the keel has a flange on top that is through bolted into the bilge. The nuts have corroded to the point that they are basically just a big glob of rust on top, I'm getting hauled next week to replace the keel bolts which will hopefully allow me to sleep a little better a night

I've already replaced the mast step, it has 4 of the 14 keel bolts in it, so I'm at least familiar with the processs.....bang out bolt, replace, bed the bolt in 5200 and cover with epoxy, fair, paint

the leak looks like it's coming in through the crack around the keel (which goes all the way around) right at the center in the front....from what I've read this can be caused by a grounding....when I put in the mast step I threaded the holes in the mast step, screwed in the new bolts and put a washer and nut on top, it seemed like a good idea at the time but not I can't tension those four bolts since they're basically screwed into the mast step

my thought is this, go ahead and remove all the bolts (the nasty old ones and the new ones holding the mast step one at a time and replace them one by one (use a hole saw to cut the the threads out of the mast step since that was just a bad idea)

then should I grind out the crack all the way around and fill with woven roving and cover with a strip of glass? or should I grind it out and fill the crack with a polysulfide? or should I drop the hole keel and rebed it? any other ideas?

time/money is a major issue.....but of course I don't want to go through all this and still have a leak

I suspect if I was able to tighten down those front keel bolts on the mast step the leak would go away, but I need to go ahead and replace the other ones so I can stop envisioning the keel falling off in heavy seas, and so that one day the boat is sellable

other question on keel bolts is, what kind of torque should I be adjusting these too? as hard as I can with a breaker bar?

thanks!
Brian
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Old 08-06-2010, 09:07   #2
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... or should I grind it out and fill the crack with a polysulfide? or should I drop the hole keel and rebed it? any other ideas?

...other question on keel bolts is, what kind of torque should I be adjusting these too? as hard as I can with a breaker bar?
Grind it out and fill the crack with a polysulfide (101) Polyurethane (5200), or drop the hole keel and rebed it.

BOLT TORQUE SPECIFICATIONS

Bolt Torques - Stainless Steel, Brass Aluminum Bolts - Engineer's Handbook

Keel Bolt Torques
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Old 08-06-2010, 09:28   #3
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wrong poly my bad -- yea 5200 seems like the way to go here

the first link doesn't do much for me -- I'm planning on just using steel bolts, the second link has a pretty wide variety -- I'm using 14 3/4" bolts on a 6500 lb keel, on the C&C link it suggests 90 ft lbs or 250 ft lbs, two widely different numbers

I've tried calling Chris Craft before and they're pretty sure they never made sailboats
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Old 08-06-2010, 10:01   #4
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What is the quality of your bolts? For example, 10.9 or 12.9, etc.
If you give me the material, quality, metric or withworth thread information, I can tell you the torque strength. I know bolts diameters (3/4").
By the way, why don't you use NiAlBr keel bolts and nuts?
On big sailing boats (for example, 80 ft. or 100 ft.), we use NiAlBr bolts.
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Old 08-06-2010, 15:20   #5
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what is NiAlBr? I'm definitely up for a different type of bolt if its better and reasonably cost effective
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Old 08-06-2010, 15:54   #6
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Nickel Aluminum Bronze is an extruded aluminum bronze that contains nickel and is alloyed for exceptional strength and toughness. It is used where higher mechanical properties are required. It is used in the oil & gas markets, as well as in aircraft, marine, and a host of other industrial applications. It is also used as valve stems, high strength bushings, valve guides and seats, gears, cams, ship propellers, as well as propeller nuts and shafts.
ı think that you must use this material. oyster, beneteau, jeanneau etc. uses nickel aluminum bronze for keel bolts. Swap your keel bolts with this material. if you use steel or stainless steel bolts your problem will repeat again.
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Old 08-06-2010, 15:57   #7
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... I've tried calling Chris Craft before and they're pretty sure they never made sailboats
Association of Chris Craft Sailboat Owners
Chris Craft Sailboat Division Home Page

And ➥ http://sailboatdata.com/view_BUILDER.asp?Builder_ID=191

Interestingly, the Apache Review indicates that the steel keel was adjustable (fore & aft).
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Old 08-06-2010, 16:07   #8
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with the nickel aluminum bronze, are there any compatibility issues with the iron keel? what about with the steel mast step? I don't know much about metals and their interaction

Thanks!
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Old 08-06-2010, 16:14   #9
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that is interesting Gord.....I've read that review 100 times and never noticed that caption I wonder what they mean by adjustable for and aft? I might post that on the Chris Craft Message boards....
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Old 08-06-2010, 16:17   #10
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See Dave Erickson's Chris Craft Apache 37 Home Page

Dave Erickson's Chris Craft Apache 37 Web Page

http://www.djerickson.com/apache/doc.htm

Dave says:
The Apache keel is an interesting design: The hull has traditional lines that bring to mind a full keel, but the keel is actually an aggressive (for 1968) bulbed, iron fin keel. There are not many boats made like this. This reduces wetted surface versus a full keel and as a result, the steering is more responsive than a full keel boat and the light air performance is outstanding.

The keel has a wide flange at the top and 14 large flat head bolts are used to attach it to the hull. This keel mounting is extremely strong. One of the 3/4" x 4" flat head bolts has the strength to support the 6500# keel. This design could only be done in iron: a lead flange would not have adequate strength in its flange. The joint between the keel and hull must be faired with an elastic material. When I bought her, the caulking was loose in places. I removed the caulk, cleaned the groove out and applied epoxy primer (barrier coat). I applied a hard filler, but this was a bad idea. Within a year it had cracked. So learning my lesson the hard way, I ground out the hard filler (Makita grinder) and applied a softer caulking, Life Caulk, which worked very well.
Most iron keels are prone to small rust spots in the spring. Each spring I would grind the area around the spot and apply a couple coats of Interlux 2000 barrier coat to the spots. I eventually ground the entire keel down and barrier coated it with 5 coats. Much better.
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Old 08-06-2010, 16:35   #11
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yea I'm very familiar with dave's website -- it's pretty much the only resource for the apache out there, I tried contacting him last week about all this but haven't heard back -- I assume that adjustable fore and aft just has to do with being able to tighten and loosen the bolts
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Old 16-06-2010, 19:39   #12
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Pictures....

so I ground out the crack around the keel and I think I found where the leak is coming from

Click image for larger version

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there's a few area where there are holes in the fiberglass, and there's some caulking more or less all the way around -- grinding out the caulking and glass and re-caulking with 5200 sound like a decent idea?

I'll have the yard look at it tomorrow too......but wanted some shouts from the peanut gallery
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