Cavechat.org

New to the site, been reading on it for the past few days. I do more rock climbing than anything, however I just moved to an area in missouri that has over 700 caves in the county I live in and I hooked up with the local grotto club this weekend and got introducted to the sport with these guys.

Anyway Ive noticed when rappelling into a cave, ive noticed countless talk about using something like the petzel rack, instead of a figure 8. Why is this? granted I understand you can add friction to the rack quite easily and slow down your descent, however you can do the same thing with a figure 8, right? Granted ive never rappelled into a 180 foot deep hole before.........is it due to the mud/water that gets on the rope, making the figure 8 not very good to use? When I rappel I used prussic's as backups or even an autoblock.

As much searching I have done I havn't found any discussion as to WHY the racks are used over figure 8's or even ATC's for that matter. I have all this gear for rock climbing, I just dont want to spend another $70 on a piece of gear when my ATC's or figure 8 works just fine. Thanks.

Chad

Hi, Chad and welcome to the forum.

I caved in Pulaski Co. for awhile some years back.

I've used both the figure 8 and the rack and even other rappel devices. In general, on pits less then, say, 100 ft you can use a figure 8 easily. Beyond that the variable friction of a rack makes the act safer. Figure 8 are fixed friction devices after all.

Here is a very informative web site for all devices: http://storrick.cnchost.com/

The main disadvantage you have with a figure 8 is it will twist the rope on the way down.
Not a problem for you, but it is a problem for the next guy using a rack.
On free drops it will cause the person using a rack to spin on the way down.

There is another thread about the use of figure 8's that will be helpful:
http://www.forums.caves.org/viewtopic.php?f=5&t=5925&st=0&sk=t&sd=a

Hi Chad,
The variable friction becomes more important as the drop gets deeper. As Phil says, probably not really an important difference for pits of <100'. The other important reason is that a rack can withstand a rappel on a muddy, gritty rope much better. In climbing a rope is much more likely to be clean so rapping on an ATC is perfectly safe. With a muddy, gritty one your device can be chewed up pretty quickly. I used an 8 on lots of climbing raps with no visible damage. One caving rappel significantly grooved it. I can imagine a thin metal device like an ATC failing on one rappel. With a rack the friction is spread more and the metal is thicker so it can take it, and when the bars get worn, you can replace them.

See what the experienced cavers in your area are using. They've probably chosen something appropriate for the local caves.

Well ive only met a few of the locals, but one is head of the missouri spellogical society, i think thats right........ Anwyay he has a rack. apparently most of the guys around here done rappel into the caves, however the largest cave in missouri is a few miles from my house in perryville. Its 29 miles long and there are 2 entrances. One is a crawl in, the other is a 170 foot rappel, which obviously I would rather rappel into the hole, than crawl in and walk for 2 hours just ot get to that same pit point. I just didnt want to have to buy more equipment if i could get away with it, but if I have to, I have to.

Its just that most of the caves are a few miles from my house so it will be easy to get "into" this sport, as i have to drive an hour to 2 hours to go rock climbing and 30min - 1.5 hours to go hiking/mountain biking. Thanks for the responses. Like I said, i figured the gritty rope would probably have something to do with it and i will definately remember NOT to use my ATC's when rappelling into any cave. Thanks.

Another reason that an ATC does not perform will in caveing is the difference in the ropes used. As you well know, climbing you use dynamic rope which is very soft hand compared to the static rope the we use caveing. PMI (a popular brand of static rope) is so stiff that you cannot form a bite small enough to feed it into an ATC.

Chad,

You are correct that you can always add more friction to a fig 8. Same with a rack. But, the difference is with a rack you can subtract friction. At the top of a 200' drop, the rope weight may be adding too much friction (just like a bottom/fireman's belay) to allow an 8 to slide down the rope. With a rack, you can simply reduce the friction by spreading and/or removing bars.

Also, caving rope is very different from climbing rope. Biggest difference is it's stiff. 11mm PMI Pit Rope (very common caving rope) is very difficult (maybe impossible) to simply put in an ATC. Caving rope is thick and stiff to allow it to withstand abrasion when the rope rubs the walls, especially while climbing the rope.

That said, there is nothing wrong with using an 8, or any other device while caving. I use an 8 frequently on short drops. As long as the device is appropriate for the conditions, have at it. And there's the catch. A rack is appropriate for darn near every cave (and rope) in the world. It may not be the best choice, because they are big and heavy. But, racks will work just about anywhere. Lots of cavers have and use racks because it's much cheaper to buy one $70 device that does everything, than it is to buy a half dozen devices that may be more appropriate to a particular cave.

Welcome to Cavechat!

Beat ya to it, Scott.

Heh that is something I didnt' know. I've only ever used dynamic ropes, and have never had a reason to use or buy a static line, but that makes sense as well. Thanks again for the input.

Remember when working with friction devices a problem can be "heat". A fig. 8 cannot disperse the heat as fast as a rack thus racks are better on longer drops. The more dirty and stiff a rope is the more friction is created thus the more heat.

I have use stainless steel fig 8 on a dirty and rope not only did the rappel notch the fig 8 but it was so hot at the bottom that I had to wait for it to cool down. Some static ropes I have rapped on have been gritty enough to wear thru the anodize coating of a standard fig. eight.

Personally I prefer a micro rack or other in caving and leave the fig. eight for climbing.

Great info. Looks like I should buy a rack before dropping into that 170 foot pit then ehh ;)

Do you guys have any suggestions for a brand? I kind of liked the Petzel unit as it had a $70 price tag. Any suggestions?

I like SMC over petzl. The SMC can be fitted with different bars such as stainless U-bars or aluminum plus you can add on an SS bar. I have found new SMC racks on ebay for 35-40 dollars.

IMO has a good section of racks: http://www.innermountainoutfitters.net/subcategory.php?subcategoryid=8&page=all

which ever rack in you end up buying, throw down the extra oney for stainless steel bars for it. Aluminum bars can make the rope black and a lot of cavers I know won't let guys with Al bars rappel on their ropes.

Chads93GT wrote:Great info. Looks like I should buy a rack before dropping into that 170 foot pit then ehh ;)

Do you guys have any suggestions for a brand? I kind of liked the Petzel unit as it had a $70 price tag. Any suggestions?

All previous observations/opinions/experiences with racks are right on so I won't add to that.
The observations of the 8 are likewise, yet I still do like using one. But like others only for drops less than 100 feet. I own several 8's (being an instructor) and one of them is the SMC stainless steel 8 which I've used on deeper drops. I don't know why I get shouted down about it but in my experience the steel 8 does not get quite as hot as the aluminum ones does. I've done Stupendous Pit (-201) on my steel 8 and yes I did spin around and around and around but upon landing the 8 was warm but not unbearably hot. I still removed it quickly from the rope none-the less.

On the spinning aspects that 8's tend to do I've found through trial and error that the twists and kinks at the end of the rope are primarily because there is simply too much rope at the bottom. Say using a 150' rope for a 115' drop, naturally all that twists that the device puts on the rope will cause the end laying on the floor to bunch up. But using a 125 or 130' rope for a 115' drop and the bunching is considerably less if not totally eliminated, as the twists work themselves out the end and the next person down doesn't spin as much.
One solution is intentionally short-roping the drop when using a longer rope. Meaning, that the first person down can holler up for the caver on top to haul up the rope til just a few feet are laying on the floor, the topside caver can then re-rig the drop (adding another wrap around the tree if using a tensionless wrap rigging, and the twists and bunching are no longer a problem. Sure, it takes a bit longer to get things set up but IMO adds a bit more life to the rope than laying on a muddy floor where landing cavers may inadvertently/unintentionally step on it and possibly damage the sheath.
I've spun on racks before, even after a rack user went down before me. The rack isn't completely spin free either.

Ralph wrote:in my experience the steel 8 does not get quite as hot as the aluminum ones does

Very true ....,

I was rappeling as close to freefall as I could get [which not a good idea] on a 180 foot drop and the eight smelled like a hot iron. But I was in my late teens (roll of the eyes).