UKC

Sad I know, but whilst fiddling, I worked out how to tie an alpine butterfly in the end of a rope which means tat you can tie it through your harness. Stronger than a bowline and easier to undo than a figure 8. Like i said it is rather sad but sometimes it is the small things in life that are pleasing.

In reply to ray:

I think thats pretty cool Ray ! pat on back & all that !

In reply to ray:

Would that be similar to the alpine butterfly knot at all? :-p

In reply to JamieAyres:
*rse, you ususally tie an alpine butterfly in a loop as a mid line knot.
tieing it in the end also means that you can use it as a bend to join two ropes together, safer by far than using an overhand knot which is often recomended

In reply to JamieAyres: doh! just noticed sp error

In reply to ray:

couldn't resist. me bad.

I have so far only mastered tieing it using the two loops and 'the little man sticks his head up his arse' technique in the middle of a length of rope.

Must learn how to tie it properly!

In reply to ray:

If using it as a tie-in, how much tail do you leave and what do you do with it?

In reply to ray:

Ooh, go on then, I can't resist. Why is it safer by far than the overhand knot?

In reply to ray:


But is the overhand knot recommended because it is the safest? Its advantage is supposed to lie in its asymmetry and ability to roll away from the rock and jam less often. I have not tried joining two ropes with two alpine butterfly knots -you may be right in saying it is a safer knot but in my mind’s eye it would jam more often than an overhand.

In reply to Clinger: in theory you shouldn't need to back up the knot as it is not prone to slipping but the less brave of us would put a half hitch on it. try it

In reply to TobyT: it does not reduce the strength of the rope like other knots. the overhand knot is generally accepted as not being very strong.

In reply to NickAL: you misunderstand, i didn't say use two alpine butterfly knots, i said use the alpine butterfly tied in two ends to join them, try it, it is also asymmemetric and much stronger

In reply to ray:

*All* knots reduce the 'strength' (might want a more definite definition of that, by the way) of the rope. Some just reduce it less than others. I have no idea what % breaking strain an AB knot has though.

In reply to James Jackson: oh allright, but as knots go the alpine butterfly is as strong and secure as it comes, also relatively easy to untie after loading, which an overhand knot definitely is not.

In reply to ray:

The overhand tied in two parallel ropes for abseiling is incredibly easy to untie once you've pulled the ropes down. I see no problem with strength, regardless of whether an Alpine Butterfly is "stronger" in extremis, the overhand is safe, practical, and simple to tie and untie.

In reply to ray:

The Alpine Butterfly when tied as you suggest i.e. a terminal loop, is weaker than the other looped knots. The figures for strength quoted are for the rope being pulled along the length i.e. from one end to another. It has no advantage strength wise to any of the other looped knots.

Re-tying an Alpine Butterfly can be quite useful though.

Ropes don't snap unless subjected to massive loads; generally breakages occur through other factors e.g. contamination, abrasion etc. You may have a solution looking for a problem.

In reply to ray:
>>it does not reduce the strength of the rope like other knots. the overhand knot is generally accepted as not being very strong

Who are these generals who keep talking about climbing knots?

The overhand knot is widely seen as the most suitable for joining ropes for abseiling. The other popular knot being a double fishermans with another knot (reef or overhand) in between. Here's todays other thread about it:-
http://www.ukclimbing.com/forums/t.php?t=164866&v=1#2354633

The overhand knot is used as the definitive knot for knot strength
http://www.instron.co.uk/wa/resourcecenter/glossaryterm.aspx?ID=83
According to this arcticle
http://www.iop.org/EJ/article/1367-2630/3/1/310/nj1110.html
on face value you are probably correct that the alpine butterfly is stronger than the overhand as the former is more complex. However, other factors play a part; the alpine butterfly is a good knot for forming a loop in the centre of a rope as the two ends are 180 degrees apart. I'm not sure how it behaves when the ends are loaded with a more acute angle. Additionally rope material, size and condition play a part.

Quick googling has most sites saying that a knot will reduce the strength of a rope by about 50%. Not sure where they get that from. This site contains more believeable info http://www.bwrs.org.au/research/. The results are more deastic, have a look at appendix A and B. The overhand knot loses 75% of it's strength when wet (9mm Static Eldrid) and the Alpine Butterfly 66% (11mm Static Eldrid). A double fishermans loses 42%. Check the actual breaking force though - above 10KN for the overhand.

Also check out
http://www.xmission.com/~tmoyer/testing/
http://www.amga.com/ComparativeStrengthTest.pdf

Basically the Alpine Buttefly is stronger than the overhand, but not by a huge amount. This is measured in it's standard configuration as a mid point loop, not as joinign not. The double-fishermans is stronger than both. All knots reduce the strenght of a rope considerably, but the remaining strenght is still pretty high.

Thanks for trying out a new knot technique and telling us about it, however given the above facts and combine it with the increased complexity of the Alpine Butterfly I'll stick with the overhand knot for joining ropes.

In reply to ray: the design of a alpine butterfly knot is to take a load horizontally, eg, using it when there are three people moving together, the middle guy can tie a alpine butterfly with a large loop, then on that loop, tye himself in. that way he is isolated by the tightness of the rope between the leader and the guy at the back, this makes the middle guy's experience much more pleasurable.

well done though for figuring out how to tie it at the end o a rope thru ur harness tho

Centurion05

In reply to ray: the overhand knot is in fact very suitable for joining two ropes.

its not just a strenght issue

see theis link for some very interesting test info.

a double overhand seems to be the best

nige

In reply to Nige G:
OK forgot the link !!!! duh

http://www.needlesports.com/advice/abseilknots.htm

what i was looking for was a knot which is easy to untie after loading, which a figure eight is not, I normally use a bowline which is often regarded as weakening the rope more than a figure8 so i thought that an apline butterfly would be useful.

In reply to ray:

Try the yosemite bowline.

In reply to brt:

Second that. It's in the BMC knots booklet as Bowline variant.

In reply to centurion05:
there's a form of figure of eight you can use for tieing in to the middle of a rope also!