UKC

Hello UKC hive mind.

I am pretty confident that my idea is good and cunning, but as a sanity check in case there is some gotcha or schoolboy error I am about to hit. If this is all "TLDR" please just jump to actual question

Background

No this is not in an ecologically sensitive area, it's not half way up TPS and No, I don't want to get into an ethics debate or say where beyond the tree is in the middle of a forest in the middle of nowhere, it is not a crag. Please accept this and focus on the knot side of this (pedantically it may be a "bend" not a "knot", but I don't care)

semi static rope (9mm, petzl) threaded inside tubular webbing (beal)  to make an in-situ anchor point on a tree (with suitable cambium/bark protection too, to help the tree), 10mm stainless maillon (barrel filled with marine jbweld and cranked shut tighter than a duck's rear so it cannot come undone even by "magpies"). Purpose of the tape is to protect rope from sunshine and the tape is black so it is more discrete, perhaps it will provide some of its 22kn strength as a bonus.

The actual question

Rope inside tube tape... knot used to join ends of this composite "rope" --> double fishermans

I'm pretty confident this will work. Beyond length of tails and more difficult to inspect the rope condition, is there a school-boy error I am about to make? any "gotchas" I'm not spotting?

if I understand this correctly you have a rope inside a loose sleeve and want to knot the ends together. It may well work but I would run terrified as I have no idea how having a rope inside a sleeve behaves in knots - it may be twice as strong, or could for example the inner rope glide through the sleeve leaving just the tape - and I don't know how tape works if the inner pulls out and you are left with a tape tied with a double fishermans.

I can't see any faults with it, apart from getting the bend inside the tape - you'll probably have to wrap that separately.

One thing I'd be tempted to do is to clove-hitch the rope around the tree before joining the ends - that will help stop it moving and also keep the tree protection in place. I assume you'll be checking this periodically - the tree growing shouldn't be an issue with that, as it "should" just stretch the clove hitch on the way.

Described like that... my plan doesn't sounds as brilliantly cunning as it did when first in my head. my planB is to cut the tape when tying (in situ) so that the knot and tails are outside the tape, then the tape would just be a long thin rope protector, but that feels a shame like I'm not using the tape for any strength

I'd assumed the tape wouldn't be inside the knot, just butted up against it and the knot wrapped separately.

you could cut the tape down its length say a foot from each end so that inner rope can be together with a double (or triple, why not) fishermans. and then use the split tails of the tape to tie a water knot or something.

Feels like the tape then becomes something slightly more than useless but it's outside my area of knowledge as to whether it adds anything valuable.

It seems a shame to have tape and not be getting anything out of it, strength wise

https://i.imgur.com/MNt7MLK.jpg is with a triple fishermans. Snyggapa has put me off the idea of double fisherman

Edit: I emailed Ryan Jenks, but even if he does test? chances are it'll be a long time to get the results of a slow-pull failure

it's the sawing or sliding action that causes the damage to trees; pulling the rope down after an abb - rather than just pressure itself.

the tape will add little additional surface area to spread the load, possible no more than just doubling the rope. Sheath & core rope really doesn't need extra uv protection, especially not from tape. Use a rope-protector if you really want....

I think you're over-thinking this.

set the thing up with rope, drag the rope through a muddy puddle of you want to make it blend in, then remove when you're done, or when it's uv-degraded or otherwise untrustworthy - whichever comes first, please don't leave it there forever.

Hmmm...  maybe, better than only rope protector. I'm thinking that would be a pain to do in the field, due to cutting/melting etc. The tape self destructs and frays rapidly if cutting a slit with a penknife. Shoving in a dowel inside and using a hot knife is the obvious solution but not as easy in a forest (I don't know exact length)

The main problem I see with this that the rope cannot be inspected once in situ. Unless you are undertaking to regularly maintain the gear I'd err on making it easy to evaluate rather than trying to protect it.

Good point, was on the back of my mind. maybe I'm better off just using the tape and keeping the rope for another purpose. 

In reply to daWalt:

Thanks, maybe just the 25mm tape (after all it is 15Kn when new, unknotted)  or a bit of 11mm black rope then. The idea is to leave it in-situ for others due to where/what (which I am too shy to discuss)

Thanks all, what initially seemed like a brilliant idea in my head, seems far less brilliant after discussion with you lot

Interesting...  the excellent Mr Jenks said   youtube.com/watch?v=TIPxuJ22bbc&   

I had totally missed that one, not being a highliner myself. So it seems that

1) It  is very *likely* to be safe to have rope inside nylon tubular tape - tests with fig 8s it behaves nicely, I'm 100% confident that triple fisherman is not going to slip and behave weirdly, and I completely expect (not tested!)  double to be fine also

2) It's not stronger, with single dynamic rope. On slow pull, the rope stretches and the tape fails first followed by the rope shortly after. This was not tested with static rope though and my *assumption* is that static might loadshare and be better. But worst case is if it fails the same way as dynamic it is no weaker

3) fair point made by gravy and others  above that it is impossible to inspect the inner rope. You are left *assuming* that if the outer tape is good then the inner rope is good. Don't we sort of have that issue with kern rope sheath/core anyway? apart from bending it between fingers I can't actually see the core

Actually I wish I'd never asked. Before I asked I was happy in ignorance, it was surely a good idea. Now I don't know... I am tempted to do it after seeing HowNot2 tests of highline leashes... but it is no longer securely in the good-ideas box. Yes again to daWalt, when I meant forever I didn't mean forever, when it is manky tatt I will remove it, I just meant that might be quite a while it'd be left in situ

Thanks again everyone. But more confused than before

Good point, was on the back of my mind. maybe I'm better off just using the rope and keeping the tape for another purpose. 

FTFY.  Tape is very poor on fixed belays, every loadbearing fibre is exposed to UV degradation.

I'm well in favor of people taking the time, and expense, of providing good stuff on abbs rather than a jumble of rotting crap of various vintages.

I'd just say, don't install anything that you wouldn't cry over if it were gone. and don't do anything too weird.

if it looks confusing, unconventional or just odd in any way, other people just won't trust it and it'll be cut down in no time. e.g. if the outer webbing looks sun-faded the chances are the next person will just remove it, or add their own backup to it (and thereby the nest grows).

if you're spending money on stainless steel and it's going to be used by others - cheers. I don't care to debate the rights and wrongs, but bear in mind that the attitudes and ethics in climbing only slowly evolve by Planck's Principle.

This is a known failure mechanism with nylon-sheathed Dyneema/Spectra/UHMW PE-cored ropes - the dyneema is so slippery and non-stretch compared to the sheath it simply slides through the knot leaving only the sheath knotted. Triple fisherman is the workaround apparently. Certainly angling knots tied in pure Dyneema 'braid' line require about 8 turns whereas the same knot in monofilament only needs 3.

Given that an unprotected rope will get replaced as soon as the sheath gets tatty, UV protection will certainly extend the rope's life in that respect - people will inspect it and see the sheath is fine for a longer period of time.

how will they inspect the sheath ? by the time youve unthreaded it all you might as well put anew bit of rope on.

I wouldnt bother with the tape personally

In addition to what other people have said, if you want it to blend in you can buy black static rope. And if you want it to last longer you could get 12mm or thicker.

Yes, was toying with that idea,  I have a 33m black Beal intervention 11mm (if rigging or access rope needs to be less obvious. Don't ask)  but I don't want to chop 3 or 4m off the end and I'm too tight to buy some more at the moment (from Dicks) but I do have some tape etc, so wanted to use what I had.

so what i might do if wanted to mimic the tape would be to used a knackered inner tube from bike

split it, and wrap rope from both sides of the knot (after tying).  Uv nd wear protection, black (ish) and can be easily peeled back to inspect, no knots involved.

The sheath of a kernmantle rope provides UV protection and it'll be cut down or sawn through long before the meagre UK sun rots it.

Yes I'd double fishermans your set-up.

Jk