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Snow Pickets - Upright Midclips

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Snow Pickets - Upright Midclips

Postby brrrdog » Tue Apr 24, 2012 9:57 pm

Just wondering how many have read this article on snow pickets:

http://www.mountainz.co.nz/content/arti ... nchors.pdf

So the findings more or less were:
In most cases upright midclips are as good as a t-slot with a fraction of the work. Does this get anybody to dig less t-slots? Why or why not?

I'd like to try this but I'm not wild about permanently swagging 4mm cable to my pickets. I think I'm going to go with 3/16 "Amsteel Blue" spectra which should give me similar strength even with the knot. Thoughts?
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Re: Snow Pickets - Upright Midclips

Postby Ben Beckerich » Wed Apr 25, 2012 1:35 am

Did they recommend 4mm cable? That seems pretty big.. I'm not sure what size Yates uses on their L pickets, but it's not 4mm.

The point of the cable is that it doesn't lose any strength attached directly to the picket (slings/cord lose a lot of strength when hirth-hitched to the holes), and it very easily cuts through the snow without disturbing it nearly as much as sling/cord does. I wouldn't bother a mid-clip vertical placement with a bigass carabiner and chunk of webbing sticking off em... and if the reduction in strength is acceptable, then why not just use the easier and faster top-clip/hitch?

Just my thoughts on the cable question
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Re: Snow Pickets - Upright Midclips

Postby brrrdog » Wed Apr 25, 2012 2:17 am

Thanks for the reply ben.

The article specifically references the 4mm cable used in the picket by "Aspiring Enterprises" which I think is this one here:
http://www.aspiring.co.nz/tramping-snow.aspx

It gives the cable of a rating around 11kN which seems to be in line with the 2500 lb tensile strength of the wire I can find on the web. I can’t imagine the Yates model is much less unless the wire is something else other than steel.
That said, I figured the 5000 lb 3/16 spectra would be more than enough of a replacement, plus I wouldn’t have to permanently swage the cable onto the picket. I’m hoping the similar width would give me about as much snow cutting ability but I’d even consider carrying a snow saw over digging t-slots. I’d probably attach the rope with a follow thru figure 8. I think a girth hitch might twist the picket if it didn’t stay square as it was pounded in.

Note that I’m comparing the upright mid-clip to a t-slot, not to a top clip. The study led one to believe that a top-clip is inferior by HALF to a mid-clip. The only nod it gave to the top clip was when the snow is so hard (nearly ice) that trenching for a t-slot or mid-clip is not possible.
Crack open the article – it’s worth looking at just to see the pile of mangled pickets they tested with :).
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Re: Snow Pickets - Upright Midclips

Postby Ben Beckerich » Wed Apr 25, 2012 6:34 am

Gotcha... missed the cord part. I'm totally unfamiliar with Amsteel, and didn't realize something that small was available that strong. Since I don't know anything about it, I can't comment on it with any authority.. but I'd think the knot (as you mention) and the hitch itself would be pretty big weak spots, with any kind of synthetic material.
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Re: Snow Pickets - Upright Midclips

Postby brrrdog » Wed Apr 25, 2012 7:15 am

The stuff they can do with sythetic materials these days is amazing:
http://www.samsonrope.com/index.cfm?rope=192

I think we'd all be using this stuff more but it's double to triple the price of cord and webbing so I'm only considering it here for a wire replacement. With a figure 8 I should be able to count on 60 to 70% of the original strength. That still puts me well over the 10kN mark which is approaching all I can count on from the anchor anyway.

Thank you for your feedback so far.
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