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800ft rappel in the watercourse, which device to use: BMS microrack or Scarab?

Discussion in 'Tech Tips and Gear' started by Stupidjak, May 3, 2018.

  1. Stupidjak

    Stupidjak

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    I have a question about micro racks for long rappels in the watercourse.

    My friends and I use ATS devices for everything. I just ran a canyon with a 650’ waterfall in the watercourse on a Sterling 9mm CIV rope. It was a complete pain, I had to feed the heavy rope up through the device for the first half of the rappel. I’m planning on doing some 800’ waterfalls soon and am considering getting a rack so that I don’t have to feed the rope. I’ll likely be using an 8mm rope (Bluewater, Canyon Extreme).

    Considerations and questions:

    I’m considering a BMS microrack, short frame, duel hyperbar vs. titanium Scarab. Cost isn’t an issue. I really don’t want to have to feed heavy rope and I hear that it’s dangerous with racks to feed cuz the bars pop off (this is terrifying to someone like me who hasn’t used one BTW). Does the Scarab have enough friction with its single bar to start out without any wraps and then allow to start adding wraps half-way down? Is the one wrap+1bar on the scarab have little enough friction to allow starting a no-feeding 800’ rappel?

    We like to zip down fast and almost always have water cooling the device.

    I like only having to have my right hand needed to brake with the ATS, because I might have to use my left hand for something else, especially if I’m getting blasted by a lot of water. The rack seems to need a left hand to position the bars, so maybe dangerous? Are racks OK in major watercourses (like where you are holding your breath and can’t even pop your head out)?

    Can you use an autoblock on a rack? They seem like bars can pop off and reduce friction (or I might need to use my left hand and therefore accidentally lose friction) and an autoblock might be a nice backup.

    In my experience, every rappel device that has ever claimed to be able to “easily add friction” during rappel (adding a horn to a Squrl, ATS etc.) is complete BS. When I add a horn the amount of friction added is way too extreme. This ends up making the rappel either too fast or too slow. Adding a second horn means stop. The Scarab adds horns and I’m worried the same phenomena may happen. I hear that the hyperbar on the microrack has the same issue, so I’m imagining using them only when locking off. The rack seems superior because there is never a need to wrap a horn.

    When you near to the bottom of an 800’ rappel on a wet, stretched-out, 8mm rope, will a microrack offer enough friction without engaging a show-stopping hyperbar?

    Thanks in advance guys! I tried researching this stuff but couldn’t find these answers.
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  2. Rapterman

    Rapterman

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    WOW
    Those are LONG rappels in waterfalls!
    What devices / techniques are Dave Black and crew using in Hawaii? (they guide there, I am told)...
    and you will need different rope than BW 8mm (they don't make em that long)...
    Last edited: May 3, 2018
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  3. townsend

    townsend

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    Mr. Kuenn will hopefully tune in and comment. As an experienced caver, he knows the ins and outs of racks like the "back of his hand". Be careful out there.
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  4. SARguru

    SARguru

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    If you dont want to deal with horns, I would say its pretty simple solution.

    While I have not used the Scarab, I have 2 BMS micro racks with hyperbar since late 90’s. Longest single rope rappel I have done was 300ft with 7/16. The rope was not in a bag but hung all the way to the ground, i didnt have any issues or need to feed rope into the device.

    Last year I tried the BMS rack with 75ft of 7.5mm 100% technora and found it very easy to control. The only concern I have with using it in a water fall is that removing the rope from the racks 2 bars may become a problem. For this reason I have been planning on a Titanium Scarab, since I am in water canyons I figured the Scarab may be the easiest device to remove in water of all devices since I dont need to open a biner.

    Nic


    Sent from my iPhone using Tapatalk
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  5. Kuenn

    Kuenn

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    What we rack-o-teers call "rope jacking". Very labor intensive...will slap w e a r y o u o u t on a long rappel... where fatigue is a dangerous variable. Jacking rope is a sure sign that you don't have the rappel device physics figured out yet.

    If we're talking Micro - you hear correctly, my friend. It's more than dangerous - it's potentially fatal. This "design difference" is pretty much exclusive to a micro. Examine the bar "cutout slots" between the standard rack and micro (below) and you will discover the issue. Friction is the only force holding the micro bar to the rack. Jacking rope causes that opposite force friction to either go away or be significantly diminished....not good!

    14" Standard SMC Rack (left) vs 10" micro-rack (right)
    IMG-0271.JPG

    Not a fan. Good device, mind you, just lacks the versatility of a rack. You won't find one in many vertical circles that I know/hang around. For the rest of your Scarab questions I would talk to someone who is proficient at using it, proficient being the action verb...if there is someone out there.

    Lightening round:

    "Are racks OK in watercourses?" Yes, have used them often in waterfalls. All safety precautions apply, but they perform excellently.

    "The rack seems to need a left hand to position the bars, so maybe dangerous?" Not true, does usually require both hands for the first few feet when starting out and getting the friction dialed in. After that you can ride one handed unless there are friction adjustments needed. True with any variable friction device.

    "The rack seems superior because there is never a need to wrap a horn." Copy that. Many have added horns to their racks (not I), but it's superfluous, IMO. And I can lock a "hornless" rack off too.

    "When you near to the bottom of an 800’ rappel on a wet, stretched-out, 8mm rope, will a microrack offer enough friction without engaging a show-stopping hyperbar?" 90% of the time you will most likely need to go to the hyper bar toward the end of the rappel. Especially long rappels. "on a wet, stretched-out, 8mm rope" you are going to need to be very attune to your speed. Those are some serious variables...the risk is in reverse order. Diameter being the highest, IMO.

    "Can you use an autoblock on a rack?" (bleep) NO! Why the (bleep) would you want to? (I think my detestation for autobloc is bleeping through.)

    Great! Purchase a ticket to Sweet Home Alabama and I'll "show you the ropes!"

    Personally, not knowing your skill level, I would recommend the standard 14" rack - GO stainless - U bars. Aluminum is for the....(oops, Freudian slip). With some training it will become the Cadillac for long rappels, 500+ YMMV. Can you get by with less? Sure, some have and some have not. As for the micro, it's not a one trick pony but it is an advanced device, IMO. My micro is 10 inches, I have a shorter one, prefer the longer one, if you decide to go that route.

    You need to do a lot of field testing, regardless of which option you choose so that you can get familiar/safe with it. Find a 100' drop and hang 20lbs of weight on the bottom. Then wear it out with testing. Have a partner adjust the weight. Just remember, when you're gasping for air in that air-pocket you don't want to be worried about the mechanics of a new device.

    IMG-0273.JPG
  6. Stupidjak

    Stupidjak

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    Thanks for the response guys,

    Rapterman, actually they can make you a special long rope if you ask.

    Kuenn, wow! So many awesome answers to my many questions! Thank you!

    I’ve never been to Alabama, but perhaps a vacation to Hawaii would make more sense for your time?

    Just to clarify, when talking about the Scarab you said “Not a fan. Good device, mind you, just lacks the versatility of a rack. “ What did you mean by versatility? I’m just trying to go down safely and controlled without having the “jack the rope” as you say. Not trying any special rescue functions etc. (hopefully LOL)

    It seems the pros for the full rack over the micro-rack are safety. Legit pros, just so damned heavy...

    Thanks for the testing advice, yes, we do a rappelling bootcamp for anything new such as a rack.
  7. hank moon

    hank moon lovely ligatures

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  8. Rapterman

    Rapterman

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    Last I checked with the owner of Bluewater Ropes, their dyneema core 8mm canyon rope lengths were limited to about 660 feet (200 meters) or a little longer
    because of the available fiber spools that run on the rope weaving machines...
    but maybe things have changed...
    :)
  9. Kuenn

    Kuenn

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    The rack's versatility, as in one device being capable of adjusting to any rope weight/length, is basically limitless. I've used it for depths of 18' up to 2650'; same friction adjustment principles apply regardless....that's what I mean by versatility. The Scarab is going to hit a wall at some depth/length/weight, then you're back to being "jacked up" or down, whatever the case may be.

    You commented about (besmirched) the rack's weight...no disrespect intended, I'm sure. Funny thing I've chronicled over the years, the folks that bleat about the weight of this device aren't the ones that actually use it. Why? Because the ones that use it have cataloged (either verbally or mentally) the numerous times the rack has literally saved their bacon, when another device would not have measured up. A paltry few more ounces are well worth the trade-off!

    Yes, it has some weight, I'm not oblivious of that. Perhaps, the next time you're packrafting the Colorado, it can double as a boat anchor. ;)

    For the record, I just weighed the devices in the previous post: 14" rack = 25 ounces, 10" micro = 16 ounces.

    (I see where Onrope1 has the narrow 14" SS rack on sale. May just have to get me one at that price.)

    Who's buying?? :woot:
    Last edited: May 5, 2018
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  10. Stupidjak

    Stupidjak

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    must have changed, they have done 1200ft
  11. Stupidjak

    Stupidjak

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    This NZ company got back to me fast! Their 9'' 5-bar option is only 133g compared to 708g for a standard 14'' rack with 6 bars. They just told me that they can make a longer rack with 6 bars. It looks like to me that only 10.5 inches of the 14'' rack are actually used for the bars anyways. It seems to me that the bonus of the 14'' rack is the versatility of having 6 bars for maximal control. Also, I'll never use a double rope with a rack (as I will only be using the rack for long rappels and my ATS for short <250 ft drops) so I think the narrow bars should be OK.

    So it seems to me that an 11inch 6-bar titanium rack would be ideal? Does the canyoning world agree?
  12. joeb

    joeb middle aged guy who lies around alot

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    Stupidjak

    What island are you on - I now live in the Big Island and am always looking for other canyoneers out here - have not used a rack before and would be interested in learning how to use one as well


    Sent from my iPhone using Tapatalk
  13. hank moon

    hank moon lovely ligatures

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    The main advantage of the J-frame design, over U-frame, is the ability to have fewer bars engaged, while maximizing bar travel for those in use. See photo below: 4 bars in use (the minimum number for safety), 2 bars ready to be added for more friction as needed. Before buying a custom job, you might borrow a standard 14" J-rack and experiment to see how many bars, and how much bar travel you need for your rope/conditions, to avoid jacking at the top, with enough friction near the bottom. A hyperbar can be simulated as shown in the drawing below.

    14rack-2.

    Screenshot 2018-05-07 09.06.04.
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  14. Stupidjak

    Stupidjak

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    We're on Oahu but I'm from the Big Isle originally. This isn't Joe as in joesjunglegym on Instagram? If not check him out.
    also check out 808Canyons on Facebook.
  15. Stupidjak

    Stupidjak

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    Oh I didn't realize that the extra length holds the extra bars, I gotta lot to learn, thanks for sharing!

    I guess an even longer U-frame (14'') would do the trick.
  16. Kuenn

    Kuenn

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    @Stupidjak, let me indulge in just a few more comments while we're on this "rack" topic... for the 2 or 3 people on the forum that really give two hoots about it. ;)

    For the rest of y'all, feel free to cruise on past this post.

    I sense you're being drawn to the titanium U rack like a moth to a street light, mainly because of the weight issue. And that's ok, so long as caveat emptor. Before you discount the J on weight alone, let me give you a little more to chew on.

    I totally agree with Hank's advantage stated, but to me it is not the main advantage of a J vs U frame. Let me comment on the number of bars deally, first.

    It is rare, and I mean rare, that you will adjust friction on a rack during a single rappel of more than 1 bar, e.g. dropping or adding a bar. Did I say rare?! When you get into the 600-1000 footers that "may/will probably" change. Over 1000 is the only time you will mess with more than that, and you're going to want a longer rack frame for those... 18", 24", so that's really off-topic here (yeah, at those depths we're not worried about weight either).

    Adding/dropping a single bar is rather common however, and is the beauty of the rack. So, one of the first things you will want to do is determine how many bars your body weight needs for control on say a typical 200 footer and then add a couple of more bars to that. Remember, fewer bars when rope weight is high, you're trying to offset the belay variable of the rope's weight. Also, different rope diameters mean different friction conditions, so you'll want to be cognizant of that, as well. Don't hang more bars than you need on "your" rack, cause they're useless - unless you like to jingle when you walk.

    The second point, and to me the main advantage of the J rack over the U, is the superior ability (speed and ease) to add/drop a bar and the adjustment variables when doing that exercise. "But you just said that you don't add/subtract bars that much?" Yes, but when you need and want to, time is usually of the essence, especially in water. The advantage the J offers for this process is far superior to the U, IMO (and opinions of a bunch others I know, too), as too is the friction coefficient (more on this below). Again, in my circles, the J is 8:1 over the U, in standard size racks (12" or longer). (The micro is an obvious U frame exception.)

    Lastly, the friction coefficient of the J vs U. You will want to meditate on this sentence from the titanium U rack website, "Bars 2 & 4 have a machined curved slot for opening the bars." That means bars 1, 3 and 5 are fixed, can't pop them off the rack. Therein lies a huge difference as compared to the J frame/bar adjustments. You can drop a single bar on a J frame, when you drop bar 4 on a the U frame (and by the way, that is the only bar you can/should ever drop during a rappel, and even then get ready to FLY), you are losing the friction of bar 5 as well. That translates to a much bigger friction reduction/addition. I don't know if this is making any sense to you, but it IS a big deal.

    Simply stated, I can drop a single bar on a J, where as dropping a bar on a U means 2 bars are disabled from the friction equation.

    Lots more to say and learn here, but I think I've lost my audience.

    Sooooo @Stupidjak , I hope this helps you see that it's far more than just a weight discussion.
    Last edited: May 8, 2018
  17. Rapterman

    Rapterman

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    Stupidjack, you were right!
    Scott at Bluewater says can do on the long ropes.
    I would call them direct.
    Best
    Todd
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  18. Stupidjak

    Stupidjak

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    Wow, again, amazing answers to my many questions. I had read that about the losing 2 bars with U-frame racks but didn't understand why. Actually, I still don't know why they do it, but now get what they're talking about. Soooo... where do I get one of your sexy narrow 14'' J-racks in titanium? ;)
  19. Stupidjak

    Stupidjak

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    I think I've been defeated, I'm planning on getting the narrow 14" SS rack sold by onrope:
    (I see where Onrope1 has the narrow 14" SS rack on sale. May just have to get me one at that price.)

    just one last question, in the event that I only want to use a rack for 1 single type of rappel. skinny 8mm canyon extreme rope, 700ft high, single line, wet, 160lbs canyoneer. Can I engage all 5 bars from the http://whioadventures.wixsite.com/whioadventures/ti-rack NZ ti rack, space them out maximally during the beginning, then space them closer during the end of the rappel, and still be happy? No jacking wanted, no adjusting bars wanted, no zipping down to my doom from low friction? Or is it going to have to be the Cadillac/anchor 14" SS ?
  20. hank moon

    hank moon lovely ligatures

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    No way to know about the Ti rack w/o trying it out. A 14" SS rack w/hyperbar should work, but see below for rack orientation note (fig. 8 warning included for yuks). I have no experience with the narrow rack and suspect that adding/subtracting bars is more fiddly than with normal-width rack/bars. Check your mailbox for a PM.


    Something to be aware of with racks, fig. 8s, and anything else with an eye of sufficient size.

    ===

    http://onrope1.com/descending-equipment/smc-14-stainless-steel-rack-kit/

    Why use a 90 degree rack?

    John Cole, inventor of the rack, designed it to be oriented so the user is staring straight down at the ends of the bars, not looking at them from the the side. There is a very popular idea in place in today's world thinking that racks need to be turned to the left or the right. In fact, racks are correctly oriented when the open leg is facing down & out away from the user. This orientation facilitates easy changing of the bars by swinging the rope side to side, as opposed to the front & back motion necessary if the rack is improperly oriented. When extreme rope weight is encountered, such as during a drop like El Capitan, the user will then fully comprehend the necessity to properly orient their rack as it was designed.

    Who needs it?

    - Users with a vertically aligned attachment point, such as a rock climbing harness with a belay loop (as shown in the picture above on the left), need to use a regular straight frame rack. This is because when the rack is attached with a carabiner to the belay loop (like it is supposed to), once weight is applied, the rack will orient correctly, with the user looking straight down the ends of the bars from the side of the rack.
    - Users with a perpendicular attachment point, such as a program harness or a 2-point Frogger's harness (as shown in the picture above on the right), or a harness with a metal D-ring attachment need to use a 90 degree twisted frame rack. This is because when the attachment carabiner for the rack is clipped onto the harness attachment point & weight is applied, the rack will then be correctly oriented.

    *NOTE: Figure 8 descenders tend to violently twist & kink the rope during rappels, exacerbating the wear on the rope, especially between the core & the sheath of the rope. This twisting & kinking suggests early retirement of the rope. Likewise, these descenders are very small & do not dissipate heat very well. High speed rappels are discouraged with figure 8 descenders.
    Last edited: May 8, 2018
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