UKC

I recall doing my SPA training a few years ago when top rope anchor methods was raised. I said that I used the round turn and two half hitches whenever there was a suitable tree, pole or stake available. There was a little bit of sucking through of teeth by the instructor and it was dismissed. There was never any real reason given for this conclusion and despite its rejection I continue to use it and find it an excellent 'knot'.

Now in the DartRock newsletter I read this about it:
"...When I first saw this in general use in climbing and caving in the US I thought it was lazy and not really very safe - but think about it! By wrapping the rope around an anchor, like a tree, and fixing with a couple of hitches, it reduces the rope friction and movement that weaken the rope when using bight style knots, therefore keeping the rope as strong as possible. Using this method the rope can also be released while under load – and so aiding rescue and rope retrieval..."

Is there any reason not to use it? I have never found one.

In reply to noxious: A round turn and 2 half hitches is a common knot in sailing as it is easily undone after a heavy load (which is common on moorings etc.), with the load being transfered to the object through the round turns, the half hitches just stopping the round turns unravelling. A development of it is the fisherman bend where the tail goes under the round turns before the half hitches; the only problem being that after loading it can be difficult to undo. Can't remember ever using it climbing though!

In reply to noxious: Good knot used in the right place. I suspect there is a tendency to ignore/dismiss knots that aren't widely known. I once had an MIA holder dismiss a yosemite bowline because he didn't know it, even though it's in the BMC knots booklet as a bowline variant.

In reply to noxious: One suggestion I could make as to why it could be problematic is because of wear on the tree, with static rope as it is loaded and unloaded this could potentially damage the bark as it rubs back and forth as well as damaging the rope.

In reply to noxious:
Yes, a good knot to use when you need to release whilst holding a load, but not the properties I want in an SPA top/bottom rope set up. I'd opt to use knots that are less easy to undo whilst loaded. A bowline will undo easily after loading but not whilst loaded.

In reply to noxious:

I've often used a Rt&2Hh to belay to a tree (using a bight in the rope). Perfectly secure in my view. If I've been feeling a bit of a wuss I've often used 3 or more Hh though

In reply to Darron:
I probably should've clarified I would use this knot and you're right it is perfectly secure (2 half hitches are fine), but would not use it when it was being left at the top of a crag whilst I am supervising climbers on crag. So to use "whenever a tree or stake available" is not a good idea.

Cheers

In reply to noxious:
Well just to be pedantic its a hitch anyway but I used it for my SPA and nobody said a word. It´s been one of the ways of tying to something for climbers since time immemorial, is as strong and safe as it gets and I´d trust you if you used it!

In reply to noxious:

Been using it for years in Scouting for anchoring parts of ariel runways and for plenty of other things over the years.

Don't tend to use it in climbing, as I'd usually use a sling and karabiner for what you are describing, although I'd happily use it if I ran out of them.

In reply to noxious: I think that over the years there's been a tendency to reduce the number of knots in use, on the basis of keeping things simple. However that can lead to the mentality that if something's not on the "approved" list it must be dangerous. Certainly this knot used to be used in climbing, but it seems to have dropped out of fashion, probably because slings have become more widely used.

A hitch would generally be preferred to a noose when attaching a rope to a pole or a tree, because it reduces friction and wear. Just because a knot can be released under load doesn't make it unsafe - the two half-hitches are effectively a clove-hitch tied around the standing rope, and we normally think of that as a secure knot.

I can't think of a reason not to use it.

In reply to Howard J:

Some websites claim that it can work loose if subject to "spasmodic motion" - http://scoutresources.org.uk/SR/experimental/downloads/knots_knot_notes.pdf... I've used it for mooring boats and never seen this happen.

I'm not a knotting pedant but I remember being told off in scouts for finishing off with a clove hitch rather than two half hitches. No idea if that would affect its strength etc.

In reply to noxious: I've used a variant of this (nicknamed the No-Knot) for a variety of purposes in whitewater rescue, very secure, even with a raft and a tonne or more of water yanking on it... I've seen it do tremendous damage to trees though, and would be very dubious about it on anything less than a substantial tree (of the sort not all that frequently found at the top of a climb).

Summarising the stuff below - would round turn & two half hitches cause more damage to tree bark by applying a concentrated shear force and does it have the potential to damage the full circumference of the bark?

If it's good enough to tie up a boat bobbing about on the water I can't see it being insecure for climbing and might be stronger than fig of 8 but the round turn relies on friction between rope & tree plus the half hitches are nominally unloaded.

If you put a figure of eight in the rope, loop the tail around the tree and rethread through fig of 8 then there's a compressive load on the half the circumference of the tree with nominally equal tension in the rope on both sides of the tree back to the knot. The tree bark on the side facing the load is untouched. That knot works just the same on a frictionless shiny metal pole.
The round turn(s) hold by friction and apply a twisting torque to the tree because the tension is on one side only, on the half hitches side the rope isn't under much tension. It applies a shear force to the bark particularly when the rope under load first turns round the tree. That hitch works differently on a frictionless shiny metal pole, it would twist round and the half hitches would be under load.

If you imagine doing ten turns round the tree there'd be lots of friction against the tree in the earlier turns and no tension or shear force applied to the tree by the later turns. With many turns it would hold without the half hitches (like a capstan works).

It was two half hitches when I was in the scouts and it could be used to hold a load, release the load and lower the load under the control of friction, lowering would be at the cost of damaging or killing a tree.

In reply to noxious: As alluded to above, the RT+2HH works by the round turn providing a massive amount of friction to reduce the load on the hitches. Given how slippery climbing rope is, I'd suggest not tying one round anything of a smaller diamer than your waist, or the rope will move round the tree and damage the bark. Theroetically you could tie a round turn and figure of 8 loop instead of the 2 HH, this would reduce the possibility of the hitches undoing.

In reply to noxious:

Seen the same thing but with more turns described as a "friction wrap" in, IIRC, Mountaineering: Freedom of the Hills which is a pretty much ubiquitous reference to rope technique. It was sold as one of the strongest anchors possible, pretty much full strength of the rope as the wrap takes the full load rather than any part of the knot that secures it.

By the way how's it going? Not seen you around for ages? And what's with your profile showing VS as your best onsight when I distinctly recall a valiant victory on Midas Touch at Telegraph Hole!

In reply to quadmyre:
That really was a one off!

In reply to noxious: Interesting. The round turn 2 half hitches is an old navy knot that subsequently became the standard knot for fixing a line to a suitable anchor within the fire service. It was taught to fire brigade recuits for 60, 70 maybe a 100 years and was a basic skill all new firemen had to learn along with about 11 other knots. Personnaly I dont see anything wrong with it. The problem with every type of training nowadays is that it is extremelty prescriptive (not just in climbing) and if it's not in the book you dont do it and so people become totally incapable of improvising or applying some thought to a problem.

RN

In reply to noxious:

I nearly always use a RT & 2HH on the bite to tie back to my harness when setting up a belay. Very fast, very secure and easy to adjust.

In reply to noxious:

Used to be my standard belay knot for many years when tying back to the waist. In my first years climbing I used a figure of 8 but went over the the RTATHH. Only many years later did I adopt a system using mostly clove hitches.

the fire service still teach this as the primary knot for securing a line/rope, that said they have now started introducing IRATA style training and equipment, which will use slings round anchors...