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 ragtime |
#11 | |||
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Posts: 133 07/31/07 13:14:33 |
Is there a reason why one could not use an air driven impact wrench, capable of delivering the 235 lbs of torque? It would seem that you could use one of them
in the bilge without a long shaft extension.
Gerry "Ragtime" C42 #108 |
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oscar |
#12 | |||
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Posts: 475 07/31/07 16:43:30 |
Do they have "dial in" torque? The ones I've ever used do not.....
Lady Kay, C42#76, 1989, WK 3C. Chesapeake/Fort Lauderdale.
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marvroni |
#13 | |||
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Posts: 20 08/01/07 09:38:29 |
Is there a pattern to tightening the keel bolts, just as there is a pattern for tightening lug nuts on a wheel or the bolts on an engine head?
Marv Bromley
314/2 Wing |
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oscar |
#14 | |||
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Posts: 475 08/01/07 12:05:07 |
I start at the center and alternate my way out, but that is intuitive and not something I know for a fact. When I asked Catalina for the torque value nothing
was mentioned.
Lady Kay, C42#76, 1989, WK 3C. Chesapeake/Fort Lauderdale.
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rbetzing |
#15 | |||
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Posts: 60 08/01/07 18:42:54 |
Hi Bob,
How did determine the location in the floor pan under the table to drill the access holes for the keel bolts? Can you see the keel bolts that you are trying to get access to before you drilled the holes? Seems strange that Catalina would put two of the keel bolts under a fiberglass floor pan that you can't access without drilling holes...
Ron
Desperado 2000 C42/2 cabin #708 San Diego, CA |
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jiminpuyallup |
#16 | |||
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Posts: 20 08/01/07 19:58:15 |
This may start a bit of a debate but I have a theory on the keel bolt tightening.
My theory is simple and based upon my experience with tightening the keel bolts on Pure Joy. Essentially, I do not believe it is possible to properly tighten the keel bolts to factory specifications with the boat in the water. I believe this specification is intended for when the boat is out of the water and in a "free state." I will call Catalina and verify it for certain. Applying 235 foot pounds of torque to the nuts while the boat is on the deck and in a "free state" should be straightforward. However, when there are 10,000 lbs of keel hanging below all that happens is that 235 pounds of torque get applied to the nuts…. which may or may not advance them. This doesn't guarantee that the proper seal has been achieved. Consider trying to lift 5 tons of concrete on a nut and bolt using only 235 lbs of torque. The wrench will click at 235 foot pounds, but the block of concrete will still be on the ground. This is why when I torqued my keel bolts in the water it did nothing to stop the water from entering the bilge. When I haul Pure Joy next spring, I'll torque the bolts again and report back to the list. Jim Lee #508 Pure Joy Tacoma |
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robertlevi |
#17 | |||
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Posts: 39 08/02/07 10:29:26 |
Ron, My guess is that Catalina originally tightened the bolts before installing the floor pan. You can easily see the bolts after removing the floor grating and
dust bin at the foot of the companionway. I located where to drill by holding a long pencil as directly over the bolt as I could, and marking from the
underside. Then I drilled a 1/8" locator hole from below (after first removing the teak & holly floor board) so I could see where to center the hole
saw from the top.
Bob
Nalu Kai #590 1997 2-Cabin Mk II Wilmington, California |
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yorkrose |
#18 | |||
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Posts: 262 08/02/07 11:29:33 |
Jim,
I believe your proposed theory is not quite right. The torque, which is a twisting force, is not the same as the pull along the direction of the bolt. Due to the angled threads, the pull in the direction of the bolt axis is MUCH greater than 235 pounds. It is not quite a high school physics problem, since the friction is very important, but a simple force triangle solution will give the answer. The main function of tightening the bolts is to first make sure there is enough force to hold the keel in place under all operational conditions, and second to seal the bolt holes. The necessary force is far more than the ordinary weight of the keel. In-water or out-of-water would make little difference. Otherwise the keel would be loose as soon as the boat was lifted from the ground. This is not rocket science or brain surgery. The 235 foot pounds is the recommended number, but 200 or 250 would certainly work as well. One must not tighten so much that the bolt strength is approached or the fiberglass is crushed. On the other hand, if the tightening is not enough there might be leakage or the keel could wiggle. I suspect there is a fairly broad range of torque that would work just fine. Regards, Gene Fuller Yorkshire Rose, C42 #870 |
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robertlevi |
#19 | |||
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Posts: 39 08/02/07 14:13:35 |
Here is a good reference for recommended bolt torques: http://www.boltdepot.com/fastener-information/Bolts/US-Recommended-Torque.aspx.
Note that the stainless steel column is for 18-8 alloy, which is about 20% stronger than our 1" diameter 316 alloy keel bolts.
Bob
Nalu Kai #590 1997 2-Cabin Mk II Wilmington, California |
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