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zeph
Jul 22, 2002, 10:45 AM
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Registered: Jul 18, 2002
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Is this 3:1 hauling ratchet The Better Way?
I stinks at drawings...so I made this "cut'n paste" illustration from pictures of climbing stuff . I'm too lazy to take the pictures myself...The Better Way?... Thank’s for using your pic’s Dr. Piton! Well, hope you have some imagination to interpet the illustration...
I use 3:1 if the load is really heavy or a lot of friction. I usually prefer Dr. Piton/Congo's 2:1 ratchet. So when you need more leverage than the 2:1 this system might do the trick.
My girlfriend use it more often because she's in the featherweight climbing class. She weights in at 50kg (yes, she's a babe...lucky me!). I am myself a Fat Bastard at around 90kg. So when I lead or toprope, I have to tie her to the belay. If I don't we'll "switch places" in the wall in record time if I take a screamer. Believe me.... she knows how to set up a belay withstanding upwards pull...
One time in the gym, we saw a even lighter girl than mine, belaying a big heavy dude. She was standing about 15 feet away from the wall "to have a good look" at the climber, who's toproping. The dude fell, she was pulled up a few feet ... she then started to pendulum straight onto the wall……...SMACK.……….
The gal was lucky and "landed on the wall" with her feet first...
I uttered: "You might want to anchor yourself in that bolt"
...she nodded...
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fishypete
Jul 22, 2002, 11:11 AM
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Welcome to the site Zeph! That's a damn fine first contribution! (especially the devious cut-and-pasting!)
Now I gotta go and think about it some more... could this be the better way of the 3:1???
Fishy.
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drunkenmonkey
Jul 23, 2002, 7:42 AM
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is there a distinct advantage to using a separate thinner line to haul the semi static haul line. Why wouldn't you put the haul line through the croll and seperate pulley, saves on a bit of string.
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fishypete
Jul 23, 2002, 9:47 AM
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Of course all the following speculations are just that - and without some practical comparison we will never know for sure...
HOWEVER!
I can see some potentially good advantages of this system when compared with the 3:1 "far-end hauler" type system (as we have previously been introduced to by the good Dr.)
Advantage #1
This system doesn't require continual stacking and unstacking of the haul rope! Definitely a plus.
Advantage #2
The system can be pre-assembled, and the use of a light static line (with BFK) means it can be tied onto the harness at just the right height for the situation, and not altered for the remainder of the haul.
Potential disadvantages....
Of course it doesn't fit together as well as the 2:1, and therefore will be a little less efficient. Also it suffers from the same problems as the far-end hauler (e.g. crossing knots and converting to a 2:1) and it requires an extra ascender.
However if you gotta go with a 3:1 - this may indeed be the better way! Just the improvement of not needing to continually stack and unstack the rope all the time would be great!
Any other thoughts out there??
Cheers
Fishy.
[ This Message was edited by: fishypete on 2002-07-23 02:49 ]
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zeph
Jul 31, 2002, 10:31 AM
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Registered: Jul 18, 2002
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Thinner cord:
Well..just don't really need a very thick one...reduces weight, profile etc when not using it.
Separate cord(s):
As fishypete points out it keeps the thing together. That gives you a faster setup/breakedown and less chance of dropping stuff.
It is also makes the belay "cleaner"...just stack that haulline away just as it comes out of the holding ratchet.
I really likes to keep the belay as "clean" and "transparent" as possible. One of my big issues.. Want to piss me off? Just mess up my belay. When the second comes up to a belay it is very important to right away understand the setup. Do it right. It can be hard to change/improve the belay with two people there.
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rickoldskool
Aug 1, 2002, 6:32 AM
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Ahh, Excuse me. Zeph. After long and careful review, I have come to the almost certain conclusion that your system is in fact only a 2 to 1. Actual Mechanical Advantage (AMA) is how much the machine changes distance.
The equation is :
AMA = distance input / distance output.
Assume you use a cord 6ft long. If your able to pull all six feet thru, your input is 6.
Your haul line will move 3, as the lower ascender rises and upper pulley descends, they collide after each has moved 3ft(3X2=6).
Therefore your output is 3. The ratio is 6/3 or reduced to 2/1. Correct me if I'm wrong, I'm not playing the eternal smartass here
Am I missing somthing?
HOWEVER, at the very least, it does appear that what you have is an easier to rig 2/1, than that prescribed by Dr. Piton. Each has it's cons, but I like it!
If you would like to play with a real pulley click HERE
[ This Message was edited by: rickoldskool on 2002-08-01 10:00 ]
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passthepitonspete
Aug 10, 2002, 11:49 PM
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Registered: Oct 10, 2001
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Holy Frig!
What a bunch of wankers we are! Doesn't anyone know if this is 2:1 or 3:1?
Damn! I'm supposed to be a professional engineer, and I'm not even sure...
Duh.
Anyone know Nate Beckwith?
He'll tell us in a heartbeat.
Nate knows stuff.
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apollodorus
Aug 11, 2002, 12:54 AM
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It's a three to one. If 100 lb. is pulling at the harness rope, then 100 lb. is pulling up on the rope going to the lowest jumar. The pulley and jumar on the harness rope pulls down on the haul line down with 200 lbs of force (both of those 100 loads above). So, 100 lbs at the harness equals 300 lbs pulling up on the pig. Assuming no friction, it's a 3-to-1 system.
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fishypete
Aug 12, 2002, 8:24 AM
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Registered: Apr 5, 2002
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It seems this system has been tried before:
http://www.fishproducts.com/tech/techweenie.html
then click on the link "Rescue Stuff"
At the bottom of that page there is a picture of this system (it is labelled 3:1. However the system next to it is also labelled 3:1, and it is only a 2:1, just a little typo I guess).
Check it out!
Cheers
Fishy.
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rickoldskool
Aug 12, 2002, 4:10 PM
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Registered: Apr 25, 2002
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I stand corrected and informed, Thanyou!
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skloppen
Aug 12, 2002, 4:49 PM
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Registered: Jul 14, 2002
Posts: 28
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Apollodorus is correct. At first I thought that it was a 2-to-1, so I just tried it out. I pulled the "to harness" cord 1' and the pig's stand-in (a 5 pound weight) went up 4".
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