UKC

I use a water knot/tape knot to tie the rope to my harness when climbing, does anyone know about the braking strain of this knot versus the traditional figure 8 tie-in?

To do this knot you do an overhand knot about 50cm away from the end of the rope, feed the rope into the harness, then forward feed the overhand knot (apposed to reverse feeding which is how the figure of 8 knot is done).

In reply to CookieMonster_Climber: We used to call it a Cape death knot after a couple of guys from Cape Town tried to convince us it was the way. Never had the courage to take a lead fall on it, always stuck with a Fig of 8. I dont think breaking strain is an issue, but could unravel if fallen on repeatedly.

In reply to Chris Fryer:


When I was learning to climb I was shown three different ways to tie in using a bowline, fig of 8 and a water knot. I was told the only one that is almost idiot proof was the fig of 8 and after trying to tie the knots had to agree. Therefore I always use a fig of 8. You know instantly by looking at it if it is right or wrong.

In reply to CookieMonster_Climber: I'm not familiar with your knot however I do know that with regards maintaining a ropes integrity, a figure 8 is the strongest knot that can be tied so if in doubt stick to the 8.

In reply to sandywilson:

Fig 8 are a good deal stronger than bowlines or overhand/ tape knots. However, as knots don't break, what is more important is the energy absorbing ability. Again the fig-8 is a good deal better, overhnad middling, bowline worst. The argument for using a bowline is simply that it is easier to untie, however that also means it is more likely to undo itself. Overhands or tape knots, then, are weak, poor at absorbing energy and more difficult to untie than a fig-8.

In reply to CookieMonster_Climber:

Dude, just use a figure eight.

If youve been using a 'water knot' for ages and are only just asking what the breaking strain of it is then thats a bit daft!?

Figure eight is almost entirely considered the best knot to use to tie in with. Except the bowline possibly, but that can be tied incorrecltly (and is sometimes hard to identify when its tied incorrectly) so its back to the figure eight for me.


Mat

In reply to Anonymous:

"Fig 8 are a good deal stronger than bowlines" ??

From the figures I remember, Fo8 (when tied correctly) has about 75% of the rope strength and the Bowline 70%. Hardly "a good deal". Also the energy absorbing nature of a knot will depend on how tight you set the knot. In any case it is likely to be insignificant compared to the energy absorbed by the rope that isn't part of the knot.

Bob

In reply to Anonymous:


Didn't somebody post a way of tying a Fo8 a while back that was easier to untie? I seem to recall the end was fed through the lower loop rather than tied as a stopper using a fisherman's.

In reply to CookieMonster_Climber: Tighter first bend on the lead rope will mean a reduced breaking strain. The concept of the figure-of-eight on the bight is that the lead rope (i.e the one that the strain is transmitted along) passes around the outside of the inner bight of the first figure of eight, thus increasing the radius of the bend and increasing the breaking strain at the first bend. The knot is also considered to be self-locking (as a clove hitch), whereas the knot increases the grip on the rope as strain is applied, this is obvious when one takes a huge peeler and finds the knot difficult to untie (thankfully). AN overhand knot with the loose end of the knot is not thought to be truly necessary for efficiency, but acts as a useful indicator that the end of the rope is clearly still through the whole knot.

In reply to Bob:

Bowline is as low as 50%, fig 8 around 70-75%, however as i said its the energy absorbtion that's important in climbing.
Knots have a marked effect on the energy absorbing ability of the knot/ rope system, even when pre-tensioned beyond bodyweight - never 'insignificant'.

If you want to read more - download this what i wrote...
www.hse.gov.uk/research/crr_htm/2001/crr01364.htm

In reply to CookieMonster_Climber: Yes. I know this knot. Some friends in the Czech Republic sometimes use it. It won't absorb shock as well as a figuer of 8 when it tightens, and is farly difficult to undo when fallen on.

It is safe enough though.

In reply to CookieMonster_Climber:

A tape knot reduces strength of the rope by between 58-68%, a figure of 8 by 66-77% (this is on a static rope, but wouldn't have thought it would differ too much on a dymamic rope). I have tested static/dynamic ropes at work and the results for each knot/rope type has fallen in the above %.
The tighter the bends of the rope in the knot the weaker it is. Also if it's untidy this can reduce the strength of the knot.

In reply to CookieMonster_Climber: What is the advantage of using this knot? The figure of 8 seems pretty flawless to me.

In reply to CookieMonster_Climber:

If you're "feeding forward" don't you end up with both the bulk of the rope and one side of your harness loop going into the same side of the knot? In which case, falling off might possibly lead to the knot rolling (although this is unlikely with an overhandknot ).

In reply to CookieMonster_Climber:

Sorry that i can't give you figures on it. We sometimes call it the reverse water knot.

I have used this knot since about 1990, when I was introduced to it by Swiss ace Eric Talmadge.

At that time he said it was the "competition knot" and used in the World Cups before the Fig 8 became a standard knot.

It is used by quite a few people I know who are IFMGA Guides.

It is easier to undo after being loaded and way "cleaner" around the front of your harness. There are no extra bits of rope,knots etc and is great on sport clips for that reason.

It is quick, simple and easy to tie.

Whatever you use stick with one and you will make fewer potential stuff ups. I have more difficulty now when I have to tie a Fig 8 when at the climbing wall (on their top ropes) as I so seldom tie it myself.

Thanks for all the info, i think i'll continue to use it

In reply to CookieMonster_Climber:

It was included in the AMGA manual a few years ago - haven't seen the latest edition