Plastic Corner Casting nuts

I was looking over the nuts and bolts holding the corner castings in place and found the nuts were plastic! Is this an electrolysis avoidance measure, or just someone wanting to save $5? Anybody heard of this? Surely Hobie would frown.

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Mims, FL

I replaced my with low profile( nylon insert) locking stainless steel nuts and did not over tighten them.Just hug them a bit... I also like flat washers there...
Bill 404 21SE and my trusted friend,an '81 Hobie 16...

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Bill 404 21SE

The plastic nuts are OEM supplied by Hobie Cat. Two reasons (well, maybe three) - The most important is that they prevent over tightening that can crack the castings. You figured out the other two (electrolysis and cost). This was important when new boats were delivered in boxes for the customer to assemble.

Seriously, the bolts are in shear, not tension, so the nuts take no significant load. They're there to keep the bolt from falling out, that's all.

That being said, newer boats have stainless steel nylock nuts on the pylon bolts. New boats are now delivered to the end customer assembled.

I've found that just replacing with nylock nuts using the existing bolts is not an ideal solution. A standard 3/8" nylock nut runs out of threads before it gets to the nylon locking ring which might tempt you to keep cranking down on the nut. Even though this nut is just a retainer I replaced the bolts with longer ones.

Although they aren't common, you can get "low profile" locking nuts. A pack of 25 is only about six bucks from McMaster-Carr:
http://www.mcmaster.com/#hex-locknuts/=bdx6ok

Or just use a drop of Loctite.

If you replace the bolts, you should make sure the new bolts are the same grade or higher.

sm

It appears the plastic nuts that were on there effectively did their job for thirty years. Even cracked they stayed put. I like how when I took the nut off, the bolt came out by hand with no resistance. I'm replacing them with the same.

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Mims, FL

Yeah, I knew stainless jam nuts existed but could never locate any at local home supply or hardware stores. I found 4" bolts at West Marine.

I'm a little curious why the pylons and corner castings on the H14 appear to be the same size as the 16 but use smaller bolts. Looks like 1/4".