Posted this on the Hobie forum as well but thought I would ask the experts here also.
Has anyone replaced/upgraded the nylon nuts that came from the factory on the H16? The framework attaches to the posts using nylon nuts and the rudders also are attached with nylon nuts. Wouldn't it be better to use stainless lock nuts in place of the nylon ones?

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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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do you mean nylocs?


these are tried and true for on the water applications.
i've never seen one fail (that was static)
nuts that are utilized with any frequency will probably degrade (the nylon), but these suckers work darn well.

SS nuts, washers and lock washers are not as secure (can worm free) and (more) prone to galvanic corrosion (i think)

Yes, exactly what I was talking about, thanks. I just wonder what the reasoning was in the use of totally nylon nuts, corrosion resistance perhaps? Do the new H16's still have nylon nuts?

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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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I found some info that is interesting. Nylon nuts were used so that the nut couldn't be over tightened and crack the cast aluminum corners. The newer boats do come with the stainless nylocs, just have to be careful not to over tighten.

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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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Nylon nuts were used so that the nut couldn't be over tightened and crack the cast aluminum corners.

intersting?

PS i was not even thinking about your application (on a cast alum corner) when i was talking about nylocs. I have them all over my boat (rudders, mast rotator limiter, tiller crossbar, tiller ends, etc)

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Yes, exactly what I was talking about, thanks

If you are talking about the nylock,(for decades known as aviation locknuts), as shown in MN3's photo, there are only 2 reasons they are used.
#1 - They take the place of lockwashers, & don't loosen under vibration. In aviation applications they can only be used once. In critical,(flight control) applications they are drilled & backed up with lockwire.
#2 - In stainless they offer corrosion protection.
They offer no protection against overtightening, they will turn down til either the nut, or the stud strips. If the casting is weaker, it will let go. Critical applications will specify a torque. I would never turn a 3/8" nut down to its limit on my castings.

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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Yes, it is advised that when using these for securing the frame casting corners that you tighten them until they are snug. If you really torque down on them then you run the risk of cracking the corner casting, and that will be somewhat of an expensive "ouch".
You have to keep in mind that cast aluminum is not going have much flex and will crack under stress. Now I feel as though I should just stick with the "fail safe" original nylon nuts because it would be just my luck that I would probably over tighten the nylocs and crack a corner casting. Lol.

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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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It's not that sensitive. Use good judgement and make the nut snug and you will be fine using a stainless nyloc nut. Just don't go looking up torque values for 3/8" bolts, grabbing a torque wrench, and thinking you need to tighten the nut to 20 to 30 ft-lb. All the nut is doing is keeping the bolt from dropping out.

The problem with using the nylon nuts, as you discovered, is that the nylon will eventually dry out and crack over time causing the nut to fall off - also a bad situation.

I would use a stainless nyloc and call it a day.

sm

Okay thanks. Yeah I would bet it would be a bit of a disaster if a nylon nut were to crack apart causing the bolt to slip out while out on the water.

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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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The problem with using the nylon nuts, as you discovered, is that the nylon will eventually dry out and crack over time causing the nut to fall off - also a bad situation.

I'm not saying this can't or doesn't happen but i have never seen one fail in my 19 years of owning catamarans in salty and sunny florida -

if you don't inspect (and replace) your parts every few years... your likely gonna have a failure -



Edited by MN3 on Dec 30, 2016 - 06:57 PM.

dbl



Edited by MN3 on Dec 30, 2016 - 06:57 PM.