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So I've been thinking about developing some canyons around here for canyoneering, but while scrambling up Red Rocks Canyon in Waterton and looking at all the large logs jammed rather high up in the canyon, it occurred to me that depending on where you would want to place your bolt, it could end up under water during spring run off.

My first thought was that I would simply need to place the bolt up higher so it could stay dry, but looking at where I suspected the high water mark to be in some places, you'd be bolting too high for anyone to ever reach it.

Can fixed protection be placed in areas which are under water for part of the season?

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This got me curious, & using Expansion anchors in construction applications got me looking. While I couldn't find anything specific to climbing applications & submersion, I did find a reference to 304 or 316 stainless steel being used in submerged marine environments (harsher than typical freshwater) by boat builders.

To my knowledge, no expansion anchors are available in 304 SS, so you would be limited to 316.

I did come across this fastener selector tool which does specifically mention expansion anchors being used in submerged applications (in concrete).

It is worth noting that even bolts installed in high, dry desert locations will need to be replaced sooner or later, so it is a good bet that the more extreme environment will shorten their lifespan no matter what you do.

Also, maybe of more importance here, is making certain not to allow different alloys to come into contact with one another for extended periods. Do not use two different alloys for the bolt & the nut, & if you leave your hangers on the bolts when not in use, make sure that they are stainless steel also. Allowing dissimilar metals to remain in contact with water will result in Galvanic Corrosion. Which essentially means the rusting process will happen much faster.

Just a thought, but you may want to be especially wary if the bolts are installed in sandstone with a high Iron content, as it seems to me that the Iron in the sandstone could react much more strongly with the stainless in a submerged environment. Anyone else have any observations on the effects (or non-effects) of Iron containing sandstone on anchor bolts?

My two cents; give it a try. Maybe just very carefully inspect each bolt before use after a submersion.

Edit: It may also be worth firing an email off to a manufacturer: http://www.fixehardware.com/shop/contact-us

Edit: Edit: Just did, waiting for response.

Edit(x3): Didn't hear back from Fixe, so I emailed Hilti customer service with the following question:

Hello, I am a climber & use your KB3 & TZ expansion anchors to secure my safety lines into rock. A route I am considering setting is partially submerged in melt water seasonally. Would it still be safe to use a SS KB3 or TZ that has been submerged for several weeks? (assuming of course correct embedment & compressive strength of the rock).

This Was their reply:

After speaking with our engineers, the water part would be no issue. However their question is will there be any freezing of the water. Could you possibly call in to Customer Service next week between 8:00am and 4:00pm CST to speak with an engineer on this further? 1-800-879-8000. They had a few other questions about the application before giving a difinitive yes or no. Thanks,

Jennifer Martin

Inside Sales Partner | Customer Service

Hilti North America

So it sounds as though while submersion is okay, a volume of water collecting behind the bolt, freezing & pushing the bolt out or cracking the rock is their main concern.

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  • For the record, I use Hilti KB3 SAE 304 bolts.
    – ShemSeger
    Aug 28, 2015 at 2:17
  • Huh. That one page does say 304 is good for being submerged, 316 for being submerged with chemicals in the water. So 304 bolts are apparently fine under water, but whether or not they're ok for rap anchors is still somewhat of a question.
    – ShemSeger
    Aug 28, 2015 at 3:15
  • Heh, well I'll be damned, they do make 304s. I've used these in SAR rappelling scenarios (not sure of the brand, but they where SS), & they seemed comparable to the Hilti KB3s & TZs that I use professionally, which are often rated for 1200-2000 lbs wind load, a combination of shear & pullout (dependent on the embedment & the material strength), so I'd think stresses induced by a shock load would still be within acceptable range whether or not they had been submerged, so long as there is no rust or degradation of the rock. (Still waiting for a reply from fixe though...)
    – renesis
    Aug 28, 2015 at 3:53
  • Well, I never did hear back from Fixe, so I emailed Hilti. I'll edit my answer with their response.
    – renesis
    Aug 28, 2015 at 22:20
  • Iron content in sandstone is a non-issue. Iron is rarely found in elemental form in nature. The oxidized form (which gives sandstone its colour) is not soluble in water, so it cannot cause any chemical reaction.
    – anatolyg
    Jul 18, 2017 at 9:22

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