Maintaining Bolt Torque

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Old Yeller
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Maintaining Bolt Torque

Post by Old Yeller »

What's the best way to keep these Rib bolts tight?
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Rib 2 Stringer Bolts 20200611_173309.jpg
Rib Stringer Bolts 20200611_173336.jpg

SWAMPHUNTER45
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Re: Maintaining Bolt Torque

Post by SWAMPHUNTER45 »

It looks as if your already running a poly nut on there. Were the poly nuts new or did they already have use on them?

I find after use they won’t hold as well FYI.

Tricks we have used on difficult applications have been to use a commercial thread lock like LocTite. The Red #271 is a permanent thread lock compound. If it is the nut coming loose and not bolt stretch, the #271 product will stop it.

Another less intrusive trick is to put a smear of High Quality RTV sealer such as Permatex high heat on one side of the threads and tighten it down then allow 24 hours to cure. Make sure the bolt and nut are clean and dry. The objective is for the sealer to bond and created a filler in the threads and barrier to backing off. Put a little up under the nut after tightening also. Just a pea size amount and wipe the bolt and nut base.

I suspect part of the issue is that the nuts can’t torque flat as they are drilled in at an angle so any flex is working to mechanically loosen the nut. It they were flat the added surface tensions would hold better.

Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

Thank You!

Anyone else have this "S" Section Rib bolt up issue?

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Slidin Gator
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Re: Maintaining Bolt Torque

Post by Slidin Gator »

You need beveled I-beam washers to level out under the nut. Normally you drill the hole straight and put them under the I-beam flange, but they should work under the nut for the angle the holes are drilled at.

Image

McMaster has them in SST and Aluminum.
https://www.mcmaster.com/wedge-washers/
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

That should do the trick! THANK YOU!

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Slidin Gator
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Re: Maintaining Bolt Torque

Post by Slidin Gator »

Your welcome Yeller. Not that it matters to you much more much but here's the skinny in case it helps someone select metal for a build.

You didn't get many responses because most boats are built with beams and channels made to "Aluminum Association" standards, which have constant thickness flanges, easy to bolt to. Your beams are "American Standard" which match steel shapes with tapered flanges. The tapered flange is the most structurally efficient, using the least amount of metal for a given strength, they have their place and they are saving you a few pounds. But as you show, the taper creates other issues. Your about to add back the weight savings in washers. :banghead:
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

I appreciate the help GREATLY! I'll call McMaster Monday and see if they can get me 110 5/16" in 316SS. I doubt CG will let me get away with 18-8 or an unk ali spec. Thank You Again!

Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

The brackets have complicated the "wedge washer" theory with a taper that is 90* offset from the crossmember taper :banghead:
20200909_100100 (2).jpg

Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

Anyone else with this issue on an inspected airboat that found a 176.700 approved solution?

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Slidin Gator
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Re: Maintaining Bolt Torque

Post by Slidin Gator »

Given the issues you have shown, I'd start looking for a 176.700 approved aluminum welder to eliminate this particular issue for you so you can get back to making money with this boat.
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

SWAMPHUNTER45
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Re: Maintaining Bolt Torque

Post by SWAMPHUNTER45 »

X2 what SG said

Gator why would they build the boat that way ? Does that design of beam offer enhanced strength if so it would make a layman go WTF how are you supposed to marry the beams and maintain the structural integrity.

WHY?

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Slidin Gator
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Re: Maintaining Bolt Torque

Post by Slidin Gator »

Slidin Gator wrote:
Sat Sep 12, 2020 5:56 pm
Your welcome Yeller. Not that it matters to you much more much but here's the skinny in case it helps someone select metal for a build.

You didn't get many responses because most boats are built with beams and channels made to "Aluminum Association" standards, which have constant thickness flanges, easy to bolt to. Your beams are "American Standard" which match steel shapes with tapered flanges. The tapered flange is the most structurally efficient, using the least amount of metal for a given strength, they have their place and they are saving you a few pounds. But as you show, the taper creates other issues. Your about to add back the weight savings in washers. :banghead:
Swamp,

If the holes were drilled straight, the I beam washers would be are the correct angle, just rotated 90 degrees from each other. But the off angle drill results in a different compound angle so these particular washers won't work. They could be modified at a machine shop to match the angle(s) needed, but it looks like a hair pulling jigsaw puzzle. That said, American Standard beams are normally used in welded metal work. Aluminum Association beams should have been used originally in this application.
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

Gary S
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Re: Maintaining Bolt Torque

Post by Gary S »

If you bought the boat for a inspected purpose and it doesn't pass inspection, why not take it back to manufacture and let them spend the $176? The other side is how long will it take to make the $176.00 , and what would it cost you for manufacture to do the mods. $176.00 doesn't seem like that much money to me. Bet you have more then that in safety equipment.

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kwanjangnihm
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Re: Maintaining Bolt Torque

Post by kwanjangnihm »

Gary I am pretty sure he is referring to 46 CFR 176.700 - Permission for repairs and alterations. (code of federal regulations)
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Old Yeller
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Re: Maintaining Bolt Torque

Post by Old Yeller »

Thanks for clarifying 46CFR176.700 kwanjangnihm

Slidin Gator &  SWAMPHUNTER45:  You are both spot on. We did get a previous approval on a different hull with a combination wedge washer/red locktite on jack blocks as shown. The wedges were machined from the I beam spec, properly drilled with a shouldered 5/16” in 316SS.
I’ll mention welding and bolting up with new clips to USCG and test the water… afraid we’d be chasing cracks, we’re dealing with 5 ribs each attached to 11 stringers.
Cross Member Wedge Washer.jpg
Gary S I have to submit a request for repairs and alterations to the USCG-OCMI (Officer in Charge of Marine Inspection) detailing the modifications. Inspected are built to USCG Approved Plans and we are held to them. Also, the 176.700 may not be a permanent solution, I have seen USCG overrule a mod years later and have it returned to the original approved plan. My first request to ”accept as is with the 5/16” x (?) bolts and jack blocks” has been working it’s way up Chain of Command for more than six weeks now, I’m no longer hopeful it will be approved. My hope is to get ideas and submit another request that avoids the OCMI ordering the infamous “crop & renew” (a/k/a cut it all out and start over) directive.
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Crossmember attachment.JPG

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