Double portaledge- which one is best ???

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Nefarius

Big Wall climber

Fresno, CA

Aug 21, 2007 - 06:04pm PT

"Also, gone are the days of placing the short side of the ledge against the wall. Impossible with either of the new BD ledges. Quite possible with the FISH and Metolius. "

Just *barely* possible with the Metolius single, Kate. Barely. Until you get on the thing and stretch them out a bit, your ledge won't sit anywhere near flat with the short side against the wall.

deuce4

Big Wall climber

the Southwest

Aug 21, 2007 - 06:12pm PT

Look, there's no doubt that Fish ledges are fine rigs, and that he has an endless number of devotees. I'm out of the portaledge business anyway, so there's no challenge there.

But I would argue that tube stiffness is a valid consideration, and in this respect, aluminum is superior.

Then again, if I were to make ledges again, perhaps I'd consider steel for their compact size. A bit cheaper, too.

Regarding the conductivity of 6061-T6, it is about a half as conductive as 4130 ChroMo steel. Look it up. Pure aluminum is a great conductor, but once you put some alloying in there, it becomes a very poor conductor (has something to do with the face centered cubic crystal structure of aluminum, I believe).

Regarding the flagging, I used to product test the hell out of my ledges, dragging them up low angle, over roofs, whatever damage I could inflict on them, and never had a problem. We could get the A5 ledges to bend when we put six guys on it and jumped like hell. That kind of product testing was always fun.

cheers

paganmonkeyboy

Trad climber

the blighted lands of hatu

Aug 21, 2007 - 06:12pm PT

big wall parvenu - i had to look that up Pete...
and yeah - there are fine tune adjustments on the bottom of all six straps on this baby...

where's the TR from you two ? some of us wounded gumbies have to live vicariously ya know...

Holdplease2

Big Wall climber

Yosemite area

Aug 21, 2007 - 06:52pm PT

Hey Pete:

After belaying from your ledge (CroMoly) and mine (in the past, and aluminum), I can say that your ledge poles flexed quite a bit more.

*comment deleted about Pete's ledge being hard to put together/take apart...it was the shoe guy's fault. :)

Of course, this could be billed as a benefit, seeing as how I've had to re-put-together my metolius in the middle of the night when an irregularity on the rock caused my spreader bar to fall out, the ledge to hourglass, and an end tube slip out. Grrrr....

-Kate.

John Mac

Trad climber

Littleton, CO

Aug 21, 2007 - 07:39pm PT

I think the best double ledge or rather deluxe single ledge is Duece's design. I paid 300 for this one several years ago on Ebay. It had been up one wall in Zion and had a new unused seam seamed (taped) Fly. All in mint condition.

'Pass the Pitons' Pete

Big Wall climber

like Oakville, Ontario, Canada, eh?

Aug 21, 2007 - 08:10pm PT

Just to repeat [to Kate], the reason I need to bash my ledge together with a hammer is because the shoe repairman stitched the crab-O-flag too tightly to the nylon bed of the ledge, stretching the whole thing too tightly, and making it hard to assemble.

Holdplease2

Big Wall climber

Yosemite area

Aug 21, 2007 - 08:13pm PT

Oh yeah oh yeah...I will go correct my post. Thx for the reminder, Pete!

hollyclimber

Big Wall climber

Yosemite, CA

Aug 22, 2007 - 12:40am PT

Ha ha ha...

Holly WAS selling her old BD, the BEST LEDGE EVER, but its sold... I only sold it because I scored a BRAND NEW ONE at Second Ascent in Seattle. So, sadly, I will no longer be a girl who owns three portaledges... But, I do have tons of rain flys, if that counts!

And, for what its worth, to whoever asked, I always take my pad on El Cap. You really never know when you are going to need it, and John Dill would be mad at me if something went wrong and I didn't have a pad.

See ya

Lambone

Ice climber

Ashland, Or

Aug 22, 2007 - 01:30am PT

Holly, I have a (almost) brand new Skylounge too...that I got for $300 w/fly. Used it on NA right before you guys.

Cheers

I have 2 A5 double rainflys for sale, brand new with tags. One is the expedition and one is the breathable fabric expedition. asking $150 each. I bought them for my BD but they didn't fit, way too small.

Moof

Big Wall climber

A cube at my soul sucking job in Oregon

Sep 10, 2007 - 07:49pm PT

Duece,

A while back you said:

"Regarding the conductivity of 6061-T6, it is about a half as conductive as 4130 ChroMo steel. Look it up. Pure aluminum is a great conductor, but once you put some alloying in there, it becomes a very poor conductor (has something to do with the face centered cubic crystal structure of aluminum, I believe). "

It was bugging the crap out of me, gnawing at the back of my brain like a bored rat.

So I looked it up.

4130 tempered steel: 22.3 micro Ohm-cm
6061-T6/T651 aluminum: 3.99 micro Ohm-cm

So per my numbers 6061-T6 is 5x better at conducting than 4130, not 0.5x. Maybe an ancient case of missing the exponent?

Further... By cross section the aluminum is more than 2x the area. 0.875" OD 4130 with a 35 mil wall has about 0.096 sq-in of cross section (Russ's tubes). 1.125" 6061 with a 0.058 mil wall has 0.205 sq-in of cross section (Duece's tubes). So, even with your 0.5x conductivity the resistance of a tube would have been equal, though in reality it works out to 10x in favor of using 4130 if lightning was your concern.

In reality just about the worst metal conducts better than even a sliver of air (even ionized air), so choosing a metal tube for lightning resistance is about akin to choosing paint color to make your trailer more tornado proof.

Sorry to rant so bad, but it was just bugging the crap out of me for weeks.

deuce4

Big Wall climber

the Southwest

Sep 10, 2007 - 09:17pm PT

Hi Moof-

I just looked at your figures, and you are entirely correct, and my previous statements about the relative conductivity (or resistance in this case) were exactly as you presumed, my figures were off by the value of the exponent.

Thank you for pointing out my error--and hefty apologies that it has been gnawing you!

I think my predesposition of steel as a better conductor (which blinded me to those pesky exponents all these years) must have been from the time we climbed the Mushroom in Sedona, when lightning was striking the top and the steel pitons seemed like they were sparking. Must have been my imagination.

I wonder what you think about what would happen if lightning travelling down a crack, as it sometimes does, and came across a metal ledge. Do you think the ledge would act as a Faraday cage and protect its inhabitants, or do you think they'd be fried?

Again, apologies for my error.

cheers

mdavid

Big Wall climber

CA, CO, TX

Sep 10, 2007 - 09:41pm PT

go with fish

sleeping with two works and putting it up and dealing with a cluster from taking it down too quickly is manageable by one person hanging in their harness, at the end of a long day, pissed off.
Take another ledge and pretend you hate yourself when putting it in the bag...then try and uncluster it while even standing on the ground.

If you aren't planning the wall trip 6 months or more out then you are probably going to find a grand adventure, hang on tightly.

Moof

Big Wall climber

A cube at my soul sucking job in Oregon

Sep 11, 2007 - 01:07am PT

Ledge as a Faraday cage, now that is a thought!

Lightning down a crack?! Holy Frick!!!! I'd pay money to NEVER see that!

I'd imagine that if you were lying flat surrounded by a hoop of metal, that in general it would make it much less likely for modest lightning (does that make ANY sense? Maybe like and tame A4++?) to get much current through you compared to lyin in a hammock or plastic ledge. Of course half a second later the now toasty tubes would melt the nylon bed and you'd go for a nice ride. In that case Aluminum would heat up less for the same current, so it would be less likely to send you for a ride afterward (by 1/10th as much, not account for their respective specific heats). But Holy Frick, you just got struck by lightning, so at that point a tether ride you live to suffer through is a joyous event!

deuce4

Big Wall climber

the Southwest

Sep 11, 2007 - 10:19am PT

Pretty funny stuff there.

Moof, are you an engineer?

cliffhanger

Trad climber

California

Sep 11, 2007 - 01:06pm PT

Use braided wire instead of nylon straps to suspend the ledge and form a very loose Faraday cage. For the cage to work though it needs to be able to handle the current. Your light weight cage may be fried in a microsecond and you along with it.

For lightning protection you may only need to provide a nice pathway for the strike to follow. Run a fine copper wire from your highest pro and down maybe 100' under your ledge. The lightning is seeking the low ground and will go for the easy route you provide, passing you by, hopefully. Copper wire comes in very fine gauges. You would need only an ounce. (By the time the lightning fries the copper wire it will have ionized the air making its own pathway.)

I found this article on how a light weight metal mesh is used to protect composite aircraft from lightning:

http://www.compositesworld.com/hpc/issues/2006/July/1366/1

clustiere

Trad climber

Durango, CO

Sep 11, 2007 - 01:15pm PT

I dig my BD ledge as it is fast and reliable. Still I don't use it that often anymore.

SteveM

Trad climber

Sep 25, 2007 - 10:31am PT

I just got a second-hand BD double skylounge and after a weekend in the Welsh quarries I'm well confused on how to get it setup. The long side bars fold inwards at the hinges when the crossed bars at the end are squeezed flat.

Should there be a spreader bar on the BD skylounges? Or am I just doing it wrong?

Or has anybody got a scan of any destructions for these ledges? The BD website just has those for the new style single & cliff cabana ledges :-(

Lambone

Ice climber

Ashland, Or

Sep 25, 2007 - 05:23pm PT

Steve, I've spent many nights in the Skylounge Double, I've owned two. I'll try and help, keep playing with it, don't force it...

First make sure when you unfold it all the straps are totally loose. Flatten the long bars first, then pull down the end-cross bars, then spread it out. Just keep spreading it...once it's mostly out then put some tension on the straps and that should suck it flat. Sometimes with that thing you just need to jump on it and flatten it out with your own weight, then do the straps.

Packing it up is a little trickier. Reverse the set-up proces, but you need to make sure the end-cross bars fold up into the little gap in the fabric in the middle near the hinge before you fold the long bars at the hinge. If they don't lace through the gap they can rip the fabric, be carefull there.

Not sure how to better explain it, good luck!

I've recently converted to old school A5 because I came upon some cheap expedition rainfly's.