adjustable spectra/dyneema/HMPE footloop?

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adjustable spectra/dyneema/HMPE footloop?

Postby ek » Nov 26, 2007 7:19 am

I'm looking for an adjustable footloop made of Spectra cord. Something like the Petzl Footcord but in spectra/dyneema/HMPE. (My understanding is that the footcord is nylon? There is no Footcord Specific Notice on Petzl's website.)

Thanks for any input!
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Postby NZcaver » Nov 26, 2007 11:00 am

Suggestion - buy a length of 5.5mm Spectra for about $1 a foot. Buy small vinyl tubing from a hardward store to thread over the cord and reinforce the footloop(s) - this also helps to hold the footloop(s) open. Buy a tiny oval Maillon Rapide to attach to the upper ascender. Use a bowline as your easily-adjustable knot, or perhaps a clove hitch through the maillon with a barrel knot back up.

I have a Petzl Footape (my seldom-used loaner), but like you I don't know what type of cord they use for their Footcord. Probably better to make your own.
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Postby ek » Nov 26, 2007 11:32 am

Well I really like the idea of the cord buckle for quick adjustment...I would love to find either a Spectra footloop, or a cord buckle like Petzl uses for their footcord with which i could make a Spectra footloop.

5.5mm Spectra cord is quite strong, and I am guessing stronger than necessary for a footloop. Is there a smaller diameter that is available that might be suitable, if I go the route you suggest?
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Postby Scott McCrea » Nov 26, 2007 1:07 pm

Just curious why you want it to be adjustable?

If you only use one foot, a sewn daisy chain works well. Easily adjusted by choosing a different pocket. I 'spose you could cut a couple pockets out and make the big loop bigger to accept both feet, too.

Strength is not a huge issue for a foot loop. Just needs to support a couple of your body weight, after knotted. The more important feature that Spectra type cord offers is low stretch. The difference in efficiency between nylon and spectra footloops amazed me.
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Postby ek » Nov 26, 2007 1:23 pm

I'd like it to be adjustable to allow me the maximum possible degree of improvisation in any situation, particularly in cases where I might want to get my weight on my upper ascender even when the upper ascender is low on the rope. I don't plan to adjust it a lot (or ever), but I would like to be able to do so easily and while distracted by other things.

I use only one foot in the loop at a time, usually with the other foot over it and helping (but outside the loop).

An sewn etrier would be even easier than adjusting it with a buckle, but it would also be heavier, bulkier, more prone to snagging on things, and more expensive (especially if made of spectra).
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Postby NZcaver » Nov 26, 2007 1:51 pm

On second thoughts... you might try using a helical knot to adjust your footcord easily. Although I'm not sure how well that will work with Spectra, which may be a little stiff. It might be worth a try, though.

I would not go any smaller diameter than 5.5mm for the footloops, and even though they only normally need to hold a couple of times your weight... I do like the idea of having something much stronger there if I need it. Like if you need to do a quick counterbalance pickoff. Thinner cords also means more potential for wear, and I'm actually quite surprised how well my thin Spectra footloops have held up.

You seem to be on a quest to find ultralight gear - may one ask why? Do you have a big remote expedition coming up? Are you also switching your handled ascender(s) for Petzl Basics and going with thinner ropes to save some weight? Have you found a maillon harness that weighs less than 11oz yet? (That's what my lightest harness weighs.)
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Postby Jeff Bartlett » Nov 26, 2007 2:49 pm

NZcaver wrote:You seem to be on a quest to find ultralight gear - may one ask why? Do you have a big remote expedition coming up? Are you also switching your handled ascender(s) for Petzl Basics and going with thinner ropes to save some weight? Have you found a maillon harness that weighs less than 11oz yet? (That's what my lightest harness weighs.)


good point - i'm buying a set of gear myself and was surprised to read that you (EK) are looking for ultralight wiregates to use as cowstail carabiners. that's life support, and for my money it's worth a couple extra grams for Petzl Spirits or equivalent aluminum keygate carabiners.

both vertical and alpine caving techniques recommend the keygate style. not sure what on rope recommends.
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Postby Rick Brinkman » Nov 26, 2007 3:15 pm

The cord adjuster on the Petzl is basically a line adjuster for tents. Might try that. Don't know how well it would work with Spectra....

Here's a light weight nylon one:
http://www.rei.com/product/358151


It will be interesting to see your light-weight findings. I weighed my caving gear for a 'big' trip next year. Looks like each of us will carry about 30 pounds of caving gear. Be nice to bring that number down.
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Postby hank moon » Nov 26, 2007 4:49 pm

xcathodex wrote:for my money it's worth a couple extra grams for Petzl Spirits or equivalent aluminum keygate carabiners.


The snag resistance of the keylock design is an important advantage, but wiregate weight savings and clog/jam resistance may be more important, depending on the circumstances. Fortunately, all of these attributes are available in a single unit...

http://www.dmmclimbing.com/productsDeta ... id=&id2=39
http://wld.brtest.co.uk/Products/Karabiners/Helium/

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Postby ek » Nov 26, 2007 5:54 pm

NZcaver wrote:You seem to be on a quest to find ultralight gear - may one ask why? Do you have a big remote expedition coming up?

I'm not choosing all the lightest options--only when there is not some other advantage that I find particularly valuable. For instance, I could save weight by foregoing a metal buckle in my foot loop, or by attaching it directly to my upper ascender, but for versatility I prefer not to do those things. But generally I like the idea of carrying around less gear (i.e. less mass of gear), especially for longish trips where circumstances require that I have it with me all the time. I feel that while the benefits of light gear are essential only for expedition caving, they are still benefits during more ordinary trips.

I am going to TAG for 10 days soon, but that doesn't quite qualify as a remote expedition. :tonguecheek: It is, however, what has motivated me to do what I have been meaning to do for some time, and get my own vertical gear. (So far, I have been using vertical gear that belongs to my grotto--we have quite a few "loaner" sets.)

NZcaver wrote:Are you also switching your handled ascender(s) for Petzl Basics

Though I am tempted to do so, I am not switching my handled ascender (which I use as my upper ascender) for a Basic, because I value having an ascender that I can operate with one hand, and I am not sure of my ability to open a closed Basic that is not on the rope with one hand in a problem situation when I am cold, tired, and in pain.

NZcaver wrote:and going with thinner ropes to save some weight?

I am purchasing gear for my own perpetual use (I don't mean I'll never retire it...you know what I mean), and not specifically for a particular trip. Since I don't own my own ropes and am not ready to buy any yet, I use club ropes and choose the diameter on a per-cave basis. I've used 9mm EZ-bend and 11mm stiff ropes, and I most often go for something in between. The vertical gear I buy now is gear I'm going to be dragging around on me through vertical and horizontal parts of many caves.

NZcaver wrote:Have you found a maillon harness that weighs less than 11oz yet? (That's what my lightest harness weighs.)

Having said that weight is not the only thing that matters to me, nonetheless, my interest is piqued. I have *not* found such a harness. Please do tell!

xcathodex wrote:i'm buying a set of gear myself and was surprised to read that you (EK) are looking for ultralight wiregates to use as cowstail carabiners. that's life support, and for my money it's worth a couple extra grams for Petzl Spirits or equivalent aluminum keygate carabiners.

Why do you assume that wiregate carabiners are in any way more marginal than solid-gate carabiners? They tend to be stronger and less prone to opening accidentally, their gates are stiffer and gate tension doesn't decrease nearly as much over time, or very much at all as the result of dirt impregnation, and traditional wiregate closures tend to have the same ability to push away mud as solid-gate keylock closures (i.e. better than average but not that great).

xcathodex wrote:both vertical and alpine caving techniques recommend the keygate style. not sure what on rope recommends.

As Hank Moon says, the keygate style closure has superior snag-resistance. I don't have ready access to *Alpine Caving Techniques* but in *Vertical* Warild merely says that keygate 'biners are "ideal." Not that there is any additional risk associated with using wiregate carabiners--wiregates are not even mentioned. Beyond the issue of whether or not one's cowstail carabiners should be locking, I am not able to find specific recommendations on cowstail carabiner types in *On Rope, 2nd Edition*. Did wiregates even exist when *Alpine Caving Techniques* (1st English edition) and *On Rope, 2nd Edition* came out?
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Postby fuzzy-hair-man » Nov 26, 2007 6:02 pm

hank moon wrote:
xcathodex wrote:for my money it's worth a couple extra grams for Petzl Spirits or equivalent aluminum keygate carabiners.


The snag resistance of the keylock design is an important advantage, but wiregate weight savings and clog/jam resistance may be more important, depending on the circumstances. Fortunately, all of these attributes are available in a single unit...

http://www.dmmclimbing.com/productsDeta ... id=&id2=39
http://wld.brtest.co.uk/Products/Karabiners/Helium/


:kewl: Thanks for those Hank!

AFAIK wire gates have advantages other than just weight as well because the gate has less weight it's less likely to flap around in the case of a fall I think climbers call it gate flutter?? it's probably of more interest to climbers than cavers but might be important if you ever take a fall on your cowstails. :question:

I'd been thinking about some different cowstail crabs but seeing as I'm still dragging my 'boat anchor' maillon around with me :nana: any difference in weight might be minimal. Also I still find circumstances where I'd prefer I had a locking krab on my cowstail, pickoffs for example.

To get back to the foot loop thing; I got a bit of Spectra/dyneema tape and had this sewn into a foot loop using the sewn bit as stiffening on the bottom of the foot loop which nicely holds the footloop open so you can get your foot in easily, the foot loop is fairly tight for two feet and about right for a single foot meaning I can use 1 or 2 feet in the foot loop. I have tied spectra cord from the tape footloop up to my hand ascender and have enough cord I can convert to a mao, tied off with a bowline, because if I want to be able to convert I'd better be able to get the cord undone.
So far this setup is working well. BTW the extra cord also means the footloop is adjustable.
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Postby Jeff Bartlett » Nov 26, 2007 6:20 pm

Why do you assume that wiregate carabiners are in any way more marginal than solid-gate carabiners? They tend to be stronger and less prone to opening accidentally, their gates are stiffer and gate tension doesn't decrease nearly as much over time, or very much at all as the result of dirt impregnation, and traditional wiregate closures tend to have the same ability to push away mud as solid-gate keylock closures (i.e. better than average but not that great).


you're misinterpreting - nobody said wire gate carabiners aren't as good as solid gate carabiners. but there is a general consensus that for cowstails, the keygate style is ideal. up until a few minutes ago i didn't realize anyone was making a keygate wire carabiner.
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Postby ek » Nov 26, 2007 6:25 pm

xcathodex wrote:you're misinterpreting - nobody said wire gate carabiners aren't as good as solid gate carabiners. but there is a general consensus that for cowstails, the keygate style is ideal. up until a few minutes ago i didn't realize anyone was making a keygate wire carabiner.

I apologize for misconstruing what you said. The source of my confusion was that you cited that cowstail carabiners are for life support, and therefore should be solid-gate keylock instead of wiregate. This led me to think that you were saying that wiregate carabiners are less suitable for life support (that is, more marginal).
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Postby NZcaver » Nov 26, 2007 6:58 pm

ek wrote:
NZcaver wrote:Have you found a maillon harness that weighs less than 11oz yet? (That's what my lightest harness weighs.)

Having said that weight is not the only thing that matters to me, nonetheless, my interest is piqued. I have *not* found such a harness. Please do tell!

Sorry, it's my own *secret* design. :shhh: Light, comfortable, highly adjustable, and well-engineered (in my humble opinion). Everything you need, nothing you don't. Seriously, I was going to write up this big article about this harness, but I've never quite got around to it. It's now been about 4 years since I made the prototype, I think. Oh well, maybe one day...

As for wiregates - I like them. Thanks for the link, Hank! :kewl: I particularly like the look of the Helium, and they're not too badly priced at around $10 each. I currently use a Camp Nano wiregate on one side of my cowstail (normally clipped to my upper ascender), and a Petzl Spirit keylock on the other side. I like the "hard clip" action of the wiregate.

Regarding weight, I tried one of Petzl Basics as an upper ascender for a brief while - but I much prefer the ergonomics of a handled ascender. You could always do what a friend of mine has done, and make a working Frog system out of a pair of Tiblocs. For the rest of us normal folks, it's probably enough just to cut back a little by throwing away our boat anchor steel maillons and replacing them with nice alloy ones. :big grin:
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Postby ek » Nov 26, 2007 7:32 pm

NZcaver wrote:Sorry, it's my own *secret* design. Shhh Light, comfortable, highly adjustable, and well-engineered (in my humble opinion). Everything you need, nothing you don't. Seriously, I was going to write up this big article about this harness, but I've never quite got around to it. It's now been about 4 years since I made the prototype, I think. Oh well, maybe one day...

Or you could patent it and proceed toward manufacturing.

NZcaver wrote:You could always do what a friend of mine has done, and make a working Frog system out of a pair of Tiblocs.

How did your friend rig up the chest Tibloc? Through the harness maillon? Would that eliminate the need for a chest harness?
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