Author Topic: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?  (Read 21228 times)

Midlar

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I've been infected with the knot virus, so I have been assimilating my list of favorite knots for situations I have come across as a camper, ATVer, etc..  I have a decent list now, but I have not found a knot specifically described for the use listed in the subject.  Here's an example of the situation:  My friend gets his ATV stuck in the mud and he needs me to pull him out with my ATV.  I am about 20 feet away from him and we have 50 feet of poly rope with us.  He ties a knot on his ATV, using one end of the rope, and he hands me the other end, but I have 30 feet of slack to deal with.  If I had easy access to the end of the rope, I would love to tie a double knotted bowline, an alpine butterfly, or a zeppelin loop.  If I had a hook, carabiner, or similar that I could attach to the frame of my ATV, then I would use an alpine butterfly in the middle of the rope, but I am looking for a solution using only the rope.  Tying a zeppelin loop on a bight seems to work, but I have not seen this knot (zeppelin on a bight) described anywhere so I am thinking there must be a better way.  Tying a bowline on a bight incorrectly (as you would a regular bowline) also seems to work, but this method is also not mentioned anywhere.  Ideas?

knot4u

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I read that a few times.  I don't understand what the problem is exactly.
« Last Edit: October 10, 2010, 09:29:20 PM by knot4u »

roo

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Will this accomplish what you have in mind?:

http://notableknotindex.webs.com/midspan.html

Push a bight through the ring and execute a Midspan Sheet Bend, or one of the alternatives listed on that page.
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Midlar

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I'm sorry if my example did not make sense.  Put another way, consider that I have two endless rails (the frame of the ATVs in my example) that are 20 ft. apart, and I have 50 ft of rope.  I want to tie a strong loop around each rail while leaving minimal slack between the rails.  I tried the midspan sheetbend as you described, roo, and it seemed to do the trick, and is super easy to tie, but aren't sheetbends considered to be on the weaker side?  Do you think a zeppelin loop on a bight or bowline on a bight tied as a regular bowline (so I can tie it around the rail) would be even stronger? 

knot4u

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2 Options to try...

1.  Axle Hitch
http://www.layhands.com/Knots/Knots_Miscellaneous.htm#AxleHitch
http://en.wikipedia.org/wiki/Axle_hitch

2.  Fixed loop around rail, with remaining rope coiled around standing end

Midlar

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Thanks for the replies, gentlemen.  To be clear, I have two endless rails (ATV frames or tow rings), 20 ft apart, with one end already tied by my buddy, and I have 30 ft of extra slack to deal with on my end.  I need a mid-line loop that can be tied around my endless rail (ATV frame or tow ring).  Roo's midspan sheetbend variation does work (using a single rope, bight around the rail, see middle diagram in his posted link), but I was hoping for something with a stronger foundation, or, as a bonus, part of the family of knots I already know (bowline, apline butterfly, zeppelin).  The axle hitch appears to require easy access to the end of the rope, and I have 30 ft of extra rope on my end to deal with.  I need to be able to tie the fixed loop mid-line, at roughly the 20 ft point, so an on-the-bight loop will probably be required.  Maybe the midspan sheetbend is strong enough.  I don't know.  As for option 2, you say to tie the fixed loop around the rail, but that's my problem - what mid-line knot can be tied around an endless rail.  All the fixed loop knots that I have read about require access to the end of the rope, or they can't be passed around an endless rail.  The layhands website you sent me (great site) states one of these two problems with all of their listed double loop knots (again, assuming I must use an on-the-bight loop).  I am looking for a knot that does not have either of these two limitations, but maybe I am thinking about this completely wrong, as I would imagine this problem comes up quite a bit (rope way too long to use both ends). 

Again, thanks for the help.

Edit:  I just found this (see section 4-24, three loop bowline):  http://www.globalsecurity.org/military/library/policy/army/fm/3-97-61/ch4.htm#fig4-24
It appears to be a bowline on a bight, tied as a regular bowline, with a safety.  Seems to be a good option in addition to the midspan sheetbend.  Thoughts?
« Last Edit: October 11, 2010, 06:11:33 AM by Midlar »

Transminator

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Hi

As far as I am concerned, the KISS principle applies.
1. I would estimate the midspan sheet bend as strong enough. If in doubt, you can use the double sheet bend to form the midspan sheet bend.
2. Using the a doubled rope (bight) as an end of rope to tie any form of bowline (simple, water , yosemite, janus, double, double-knotted) or a zeppelin loop does also work. I personally would probably go for that option.

In addition: if you tie the midspan sheet bend, bowline or zeppelin on the bight, a small loop is sticking out. As an added safety for critical use, you could stick some kind of rod in it (large screw, stick etc.), which would prevent the loop from slipping back through, in the unlikely event the knot does start to slip.

Regards

Sweeney

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If I read this correctly you have twice as much rope as you need (and more) so why not put eg a simple cow hitch around your vehicle's tow ring and lead the end back to the stuck vehicle either doing the same and joining the ends with say a Zeppelin bend or fastening the end back to the stuck vehicles tow ring. This way you have double the rope and more security - or have I missed the point somewhere? Using a mid line loop presumably means you have 30 feet of slack rope to potentially get in the way anyway.

Barry

roo

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 I tried the midspan sheetbend as you described, roo, and it seemed to do the trick, and is super easy to tie, but aren't sheetbends considered to be on the weaker side?

Strength variation of knots in rope applications rarely becomes an issue, since you should not be anywhere near the breaking strength of your rope.  This is doubly true in your application where you'd want to err on using a rope large enough to make any stress riser (edges from rocks, etc) irrelevant so that you don't have to worry about the operator being hit by recoil from a broken rope.  Besides, the various orientations of the Midspan Sheet Bend may be as strong or stronger than some common loop knots, but that would be a subject of extensive testing in the rope type you wish to use.  I'd just assume that any knot is going to reduce line strength by about 50% from a perfect unbent state.

Secondly, recovery applications like this shouldn't see a lot of line motion or flogging, so security shouldn't be much of an issue either.
« Last Edit: October 11, 2010, 06:14:09 PM by roo »
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Karl the deckie

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What about a figure of eight loop?

or a figure of eight on the bight?
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knot4u

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Re: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?
« Reply #10 on: October 11, 2010, 06:20:24 PM »
OK, the original poster wants to take up a lot of rope.  While knot tiers typically are searching for the elegant solution, that's NOT the best approach here.  The way to go is to tie a knot that consumes the rope in an inefficient manner.

Accordingly, I'm liking the Zeppelin Loop on the bight.  I previously thought this monstrosity is a knot that I would never want to tie.  But alas, the original poster has presented a situation where this ugly beast is desirable.

The Zeppelin Loop on the bight that comes to my mind is tied like a regular Zeppelin Loop, except it's on the bight and ends up being a double loop plus an extra loop at the working end (3 loops total).  That non-functioning loop at the working end can be coiled around the standing end to keep excess from sticking out too much.  This loop is horrendous and is a woefully inefficient usage of rope.  Thus, it's good for the particular problem at hand.  ;D
« Last Edit: October 12, 2010, 01:34:53 AM by knot4u »

Midlar

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Re: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?
« Reply #11 on: October 11, 2010, 06:31:46 PM »
Transminator:  We are on the same page... I just wanted to hear that someone else with more experience had used fixed loops on a bight this way.  I was thinking of just using an overhand loop to protect the small loop that is sticking out, but a stick or similar would work too. 

Sweeny:  In this particular example I suppose I could have doubled the rope back to the other ATV, but I was looking for a more universal, autonomous option that I could use whenever I had too much rope.  In this situation, having the extra 30 ft of rope on the ground was not an issue.  I just wanted to learn a better method than the one we used, which was just a reef knot on a bight, tied over and over :)

Roo:  You're right - we shouldn't be anywhere near 50% breaking strength, especially being exposed to snap-back on the ATV.  I'd rather the knot spill out than have it lodged in my back.  The midspan sheetbend is definitely the easiest option presented so far, and it fits the bill nicely.  It has been added to my list of knots. 

Karl:  Figure eights either require the end of the rope or, when tied on a bight, cannot be passed around an endless rail. I suppose a rewoven figure eight on a bight would get the job done, but that would be a mess to dress and untie I would imagine. 

Knot4u:  Yes, the zeppelin on a bight is not as pretty or efficient as the standard version, but I have a ton of extra rope to work with as you pointed out.  Tying it with the alternate method listed in the following link allows me to tie it on a bight relatively easily:  http://notableknotindex.webs.com/zeppelinloop.html

I think I have three good options now:
1.  Midspan sheetbend
2.  Zeppelin loop on a bight
3.  Bowline on a bight tied as a standard bowline

Thanks guys.
« Last Edit: October 11, 2010, 06:39:06 PM by Midlar »

knot4u

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Re: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?
« Reply #12 on: October 11, 2010, 06:37:19 PM »
I think I have three good options now:
1.  Midspan sheetbend
2.  Zeppelin loop on a bight
3.  Bowline on a bight tied as a standard bowline

Thanks guys.

Those look good.  For the Bowline on a bight, I would add a Yosemite finish.  That would do three things:  take up more rope, take the working end outside of the loop (desirable here), and allow you to coil any remainder around the standing end.

EDIT:  The name of that knot is Triple Bowline or Three Loop Bowline.
« Last Edit: October 14, 2010, 12:31:04 AM by knot4u »

Midlar

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Re: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?
« Reply #13 on: October 12, 2010, 03:22:54 AM »
Good idea... I will try that.  Thanks

Dan_Lehman

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Re: Fixed loop, around an object (e.g. ring), middle of the rope. Which knot?
« Reply #14 on: October 12, 2010, 04:28:08 AM »
For the Bowline on a bight, I would add a Yosemite finish.

HOW would you do that?! ???

Quote
That would do three things:  take up more rope, take the working end outside of the loop (desirable here), ...

Huh?  What is this "taking the tail outside of the loop" ?
(A Bowline on a Bight doesn't have any tail in any loop (eye).)

Somehow I think you're talking about a different knot than what
is commonly referred to by that name.

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