|
climbingaggie03
Apr 14, 2006, 10:14 PM
Post #1 of 39
(4873 views)
Shortcut
Registered: Mar 18, 2004
Posts: 1173
|
So I'm gonna buy some cord and make a couple of prussic loops primarily for crevasse rescue, but they will probably atleast get put in my pack for trad climbing. My question is what diameter do people use for their loops? I've heard you divide the rope you're going to be ascending by 2, then add 2mm to get prussic cord diameter. But there seems to be alot of conflicting advice out there, so what do you use?
|
|
|
|
|
scrappy_cat
Apr 14, 2006, 10:29 PM
Post #2 of 39
(4873 views)
Shortcut
Registered: Jan 31, 2006
Posts: 1
|
When I was doing rescue work in PA, our prussics were minimum 7mm cord. That's the size we were given by the instructors (a couple guys out of NARI).
Currently, the FD I work for uses 7 and 8mm cord, and I've got a couple of each in my bag. The 7mm works best (IMHO) because it's strong enough, but not so thick that it makes tying in gloves a pain.
Hope this helps
|
|
|
|
|
sspssp
Apr 14, 2006, 10:44 PM
Post #3 of 39
(4873 views)
Shortcut
Registered: Jan 2, 2003
Posts: 1731
|
In reply to: When I was doing rescue work in PA, our prussics were minimum 7mm cord. That's the size we were given by the instructors (a couple guys out of NARI). Currently, the FD I work for uses 7 and 8mm cord, and I've got a couple of each in my bag. The 7mm works best (IMHO) because it's strong enough, but not so thick that it makes tying in gloves a pain.
If your are prussicing up a fat 12mm rescue rope, this might be ok. But I sure wouldn't try it on a 10.2mm.
The smaller diameter grips better, but the cord itself is less strong. Back when I carried prussics, I went with 5.5mm in order to be able to use it on skinny lead lines. 5.5mm is strong enough when new, but it needs inspecting and frequent replacement.
|
|
|
|
|
kachoong
Apr 14, 2006, 11:00 PM
Post #4 of 39
(4873 views)
Shortcut
Registered: Jan 23, 2004
Posts: 15304
|
I usually carry 5-5.5mm prussiks in the mountains for crevasse rescue, usually because I like to use thinner ropes (8-9mm).
Read some of the other "similar topics" listed down below
| |
| |
V V
|
|
|
|
|
greenketch
Apr 14, 2006, 11:17 PM
Post #5 of 39
(4873 views)
Shortcut
Registered: Jan 12, 2005
Posts: 501
|
sspssp, has it right. Your prussick cord needs to be 2-3mm smaller than the line you are going to ascend. Or a comfy size, if it is above that 3mm difference you may need to fuss with it a bit to get it to set as you climb. That being said when I started using 7.5 mm floss for glacier ropes I wasn't quite comfy with using a 4mm prussick. They climb well but I choose the fussing and using bigger loops.
Same considerations for the prussicks used when you set up a z-pulley. Take along a couple small loops that are fitted for whatever rope your using. I was part of an impromptue practice and got caught with too large prussicks. It was a bit of a PITA.
|
|
|
|
|
rhythm164
Apr 15, 2006, 10:53 PM
Post #6 of 39
(4873 views)
Shortcut
Registered: Mar 28, 2005
Posts: 964
|
I use a 7mm prussik on a 10.2 line, and it works out good, they're also very managable when used as a rappel back up.
|
|
|
|
|
gunkiemike
Apr 16, 2006, 12:51 AM
Post #7 of 39
(4873 views)
Shortcut
Registered: Oct 1, 2002
Posts: 2266
|
Whichever diameter you choose, buy the most flexible cord you can. Some of the new 5 mm cord is *very* stiff, possibly too stiff to work well as a prussik loop.
|
|
|
|
|
treez
Apr 16, 2006, 12:59 AM
Post #8 of 39
(4873 views)
Shortcut
Registered: Aug 11, 2004
Posts: 347
|
Whatever size it is, don't leave it in your pack. Put it in a pants pocket or on your harness.
|
|
|
|
|
heiko
Apr 16, 2006, 1:09 AM
Post #9 of 39
(4873 views)
Shortcut
Registered: Mar 3, 2005
Posts: 1505
|
5-6mm nylon works just fine. If you have to ascend a super-skinny rope, tie more loops. I wouldn't go for anything bigger than 6mm.
|
|
|
|
|
appleby93
Apr 16, 2006, 1:40 AM
Post #10 of 39
(4873 views)
Shortcut
Registered: Mar 16, 2006
Posts: 12
|
5mm
|
|
|
|
|
treez
Apr 16, 2006, 1:53 AM
Post #11 of 39
(4873 views)
Shortcut
Registered: Aug 11, 2004
Posts: 347
|
Hey Appleby93 -
Couldn't you just use some shoe laces? They're cheaper.
Just funnin ya
|
|
|
|
|
montaniero
Apr 16, 2006, 3:51 AM
Post #12 of 39
(4873 views)
Shortcut
Registered: Jul 1, 2004
Posts: 238
|
I use 6-7mm. You can't save much weight with these going to 5mm so why take a chance?
|
|
|
|
|
greenketch
Apr 16, 2006, 3:58 AM
Post #13 of 39
(4873 views)
Shortcut
Registered: Jan 12, 2005
Posts: 501
|
It's not so much about saving weight on the prussicks. They need to be part of the bigger system. If I chose to use rope less than 8mm for my glacier travel rope I would realize a savings. But, if I carried 7-8mm prussicks to use on that rope the savings would not be worth the hassle if I ever needed them.
|
|
|
|
|
montaniero
Apr 16, 2006, 10:21 PM
Post #14 of 39
(4873 views)
Shortcut
Registered: Jul 1, 2004
Posts: 238
|
In reply to: If I chose to use rope less than 8mm for my glacier travel rope I would realize a savings. But, if I carried 7-8mm prussicks to use on that rope the savings would not be worth the hassle if I ever needed them.
So, let's see...how many people actually climb in sub-8mm. ropes???? Really c'mon...
Most people use 8.1-9mm for doubles and 9-10.5mm for singles.
Given your 2-3mm. delta rule, 6-7mm. prussiks is what works with these ranges. PERIOD.
|
|
|
|
|
dirtineye
Apr 16, 2006, 11:22 PM
Post #15 of 39
(4873 views)
Shortcut
Registered: Mar 29, 2003
Posts: 5590
|
Write this down:
SEARCH before you post on a stupid beaten to death topic such as this one.
And it's THREE mm less that the diam of the rope you will be putting the prussiks on.
You should be using 4 turn prussiks too.
BTW, if you keep your prussiks in your pack, as already noted, they will not help you much when you need em.
|
|
|
|
|
zakr
Apr 16, 2006, 11:54 PM
Post #16 of 39
(4873 views)
Shortcut
Registered: Sep 29, 2004
Posts: 40
|
I use 5 or 6 mil, it bites much better.
|
|
|
|
|
bkalaska
Apr 17, 2006, 12:47 AM
Post #17 of 39
(4873 views)
Shortcut
Registered: Feb 16, 2005
Posts: 143
|
The greater the difference between the diameters the greater the knot will hold.
To raise yourself and a pack you're fine with 5 mm. If you are doing rescue 7 mm would be best, but 6 should be fine too. don't get anything stiff or extra strong, just get the nylon.
|
|
|
|
|
patto
Apr 17, 2006, 12:51 AM
Post #18 of 39
(4873 views)
Shortcut
Registered: Nov 15, 2005
Posts: 1453
|
In reply to: Write this down: And it's THREE mm less that the diam of the rope you will be putting the prussiks on.
If you going to insist on rules at least make it a correct rule. Prussik size should be based on a percetage not a fixed difference.
But at the end of the day rules are pretty usesless. As long as you can get the prussik to grip consistantly and safely then it is all good.
|
|
|
|
|
greenketch
Apr 17, 2006, 12:54 AM
Post #19 of 39
(4873 views)
Shortcut
Registered: Jan 12, 2005
Posts: 501
|
In reply to: In reply to: If I chose to use rope less than 8mm for my glacier travel rope I would realize a savings. But, if I carried 7-8mm prussicks to use on that rope the savings would not be worth the hassle if I ever needed them. So, let's see...how many people actually climb in sub-8mm. ropes???? Really c'mon... Most people use 8.1-9mm for doubles and 9-10.5mm for singles. Given your 2-3mm. delta rule, 6-7mm. prussiks is what works with these ranges. PERIOD.
Montaniero, you make a good point for general use prussicks. The OP was for prussicks that will be used primarily for crevase rescue. As the force in a crevasse fall is generally low and the weight saving is notable I know many that use ice floss for glacier travel. Many of them use a Randonee rope which is 7mm x 30 m for smaller parties.
I use larger ropes and/or doubles for ice or climbing but, that is not where I usually go into a crevasse.
|
|
|
|
|
dirtineye
Apr 17, 2006, 1:40 AM
Post #20 of 39
(4873 views)
Shortcut
Registered: Mar 29, 2003
Posts: 5590
|
In reply to: In reply to: Write this down: And it's THREE mm less that the diam of the rope you will be putting the prussiks on. If you going to insist on rules at least make it a correct rule. Prussik size should be based on a percetage not a fixed difference. But at the end of the day rules are pretty usesless. As long as you can get the prussik to grip consistantly and safely then it is all good.
Bite me.
3 mm less than any reasonable climbing rope is fine, and that is a standard rule.
Rules useless? YO ucan ignore the tests on 3 loop vs 4 loop prussiks, I won't.
You ever actually use a prussik?
|
|
|
|
|
montaniero
Apr 17, 2006, 3:25 PM
Post #21 of 39
(4873 views)
Shortcut
Registered: Jul 1, 2004
Posts: 238
|
In reply to: Montaniero, you make a good point for general use prussicks. The OP was for prussicks that will be used primarily for crevase rescue. As the force in a crevasse fall is generally low and the weight saving is notable I know many that use ice floss for glacier travel.
Got it, BUT since:
a) I don't think the OP intends to glacier travel for the only sake of...glacier travel (BTW, how does that???), but as an approach to a climbing objective,
b) Rarely climbers carry a climbing rope AND a glacier travel rope, just use one of the 8.1-9mm half ropes to glacier travel and
c) Given the rather newbie question posted by the OP, I seriously doubt he uses 7mm. ice floss twins to climb,
I infer he uses 8.1-9mm for doubles (if he uses half ropes at all but given his newbie question I doubt it) and 9-10.5mm for singles, hence 6-7mm will work fine for whatever rope he uses to climb.
|
|
|
|
|
adnix
Apr 18, 2006, 8:38 AM
Post #22 of 39
(4873 views)
Shortcut
Registered: May 20, 2003
Posts: 584
|
In reply to: You ever actually use a prussik?
There are far better options for the purpose they were first made decades ago. The only purpose I could consider prusik loop these days would be rappeling backup.
|
|
|
|
|
kachoong
Apr 18, 2006, 11:47 AM
Post #23 of 39
(4873 views)
Shortcut
Registered: Jan 23, 2004
Posts: 15304
|
In reply to: In reply to: You ever actually use a prussik? Never. Prusik loops are for inexperienced sissies only. There are far better options for the purpose they were first made decades ago. The only purpose I could consider prusik loop these days would be rappeling backup. |
|
|
|
|
112
Apr 18, 2006, 12:13 PM
Post #24 of 39
(4873 views)
Shortcut
Registered: May 15, 2004
Posts: 432
|
In reply to: I use 5 or 6 mil, it bites much better.
Holy sh*t! :shock:
5 mil = 0.005 inches = 0.127mm
I am suprised something that small can even hold body weight.
(I assume you meant mm) ;)
|
|
|
|
|
heiko
Apr 18, 2006, 1:54 PM
Post #25 of 39
(4873 views)
Shortcut
Registered: Mar 3, 2005
Posts: 1505
|
In reply to: In reply to: You ever actually use a prussik? Prusik loops are for inexperienced sissies only. There are far better options for the purpose they were first made decades ago. The only purpose I could consider prusik loop these days would be rappeling backup.
:lol: :lol: :lol:
|
|
|
|
|
|
1
