Multi-wrap Capstan hitch

[agent_smith]

Would like to obtain opinions for a name change for the so-called 'tensionless hitch'.

I've never personally liked that name - and in my view the name is misleading as there is indeed tension and friction at play.

The principle of this type of hitch is well understood via the 'Capstan equation' (google for a mathematical treatment).

Two images are attached for examples of the 'Multi-wrap Capstan hitch'. One image obviously has too few wraps. The precise number of wraps is determined by the friction interface and contact angle (in radians) of the rope is at turns around the radius. In general, at least 3 wraps are used by most vertical rescue teams. Obviously, the use of this type of hitch requires a tree, a post or some type of bollard. It can be used around SHS and RHS steel members too (although less effective than a circular profile), but padding is required to protect the 4 edges.

This obviously has practical application in rope rescue situations - but its the naming convention that this post is about.

Has anyone given much thought to the current common use of the name 'tensionless hitch' - and wondered if it really is appropriate?

Mark

[Sweeney]

I agree - the name "tensionless hitch" is daft and I do like capstan hitch as being a pretty good description of what this actually is. If there is general agreement then we perhaps need someone to put up a short YouTube video to try and get the name well known.

Barry

[knot4u]

Not trying to be a jerk, I like "Tensionless Hitch". It reminds me that there is not supposed to be tension at the working end. All (or most) of the tension in the standing end should dissipate in the coils before reaching the working end. This knot is unique in that regard.

By the way, your pics make it look like you have a fair amount of tension at the working end. As I understand, that's NOT the intent here. Further, any tension that your Prusik creates should not communicate directly with the tension at the standing end, right? The Prusik is there just so the working end doesn't flop around as much (?). So, that's another misleading part of your pics. You actually have two separate knot systems going on there, but it doesn't look that way at first glance.

[knot4u]

A quick search shows a few sources saying the Capstan Hitch is another name for the Tugboat Hitch. So, if you call that hitch in the original post the Capstan Hitch, you're introducing more confusion into the atmosphere, rather than clearing things up. Anyway, many knot names are merely an identification and not a description of functionality. For example, what the heck is a Double Dragon?

[Sweeney]

Not trying to be a jerk, I like "Tensionless Hitch". It reminds me that there is not supposed to be tension at the working end. All (or most) of the tension in the standing end should dissipate in the coils before reaching the working end. This knot is unique in that regard.

I don't see how this hitch is in any way unique I'm afraid. Does any hitch have tension in the working end? The tension is taken up by the wraps albeit they are not simply round turns but more convoluted - the end result is the same though as all hitches work through the simple fact that the friction generated is too great for the hitch to slip. To me "Tensionless Hitch" implies a hitch where the standing part is not under tension which, though possible, is a bit unlikely. In fact it could be argued that this is simply round turns and doesn't deserve a name at all beyond that. Adding a prusik makes this a different beast altogether (why not just add a rolling hitch made with the working end?).

Calling the Tugboat Hitch a Capstan Hitch is illogical - the "Tensionless Hitch"  is the way in which winches (ie capstans) work whereas the Tugboat Hitch is a hitch for a fixed post etc. and has nothing to do with Capstans. I think a renaming would remove some confusion but knot naming has no rhyme nor reason in so many cases I suppose one more makes no difference.

Barry

[knot4u]

Not trying to be a jerk, I like "Tensionless Hitch". It reminds me that there is not supposed to be tension at the working end. All (or most) of the tension in the standing end should dissipate in the coils before reaching the working end. This knot is unique in that regard.

I don't see how this hitch is in any way unique I'm afraid. Does any hitch have tension in the working end?

Um, the Buntline Hitch uses tension to secure its Two Half Hitches. The Timber Hitch requires tension at the working end to secure the working end against the object. In contrast, the Tensionless Hitch is designed to dissipate the tension in the coils before reaching the carabiner, or whatever you use to secure the working end to the standing end. In the pic in the original post, tension at the working end is manufactured by the Prusik.

Calling the Tugboat Hitch a Capstan Hitch is illogical - the "Tensionless Hitch"  is the way in which winches (ie capstans) work whereas the Tugboat Hitch is a hitch for a fixed post etc. and has nothing to do with Capstans. I think a renaming would remove some confusion but knot naming has no rhyme nor reason in so many cases I suppose one more makes no difference.

Maybe I wasn't clear. It doesn't matter if it's illogical. The association between Tugboat Hitch and Capstan Hitch is already out there in print. Renaming adds confusion because those other illogical associations will still be there, whether you like like it or not. Then, every time you refer to "Capstan Hitch", you'll have to go into a lecture about which Capstan Hitch you mean and which Capstan Hitch you don't mean, instead of just going about your business and using the knot.

[Dan_Lehman]

I have some photos to share of <whatever_you_call_it> hitches,
but those will have to wait.

I like the use of the prusik hitches (which can help
to ameliorate torque on the object), but see a better
arrangement for at least relatively larger objects:
have both the SPart and the tail joined by a sling
"prusik'd" to them (which implies that one of the
friction hitches would need to be tiable with the bight
end of the sling --Bachmann h., maybe?!)
The point to my rearrangement is that for some
case of having a lot of tail, anticipating some need
to feed out material (to lower ... ?), one could tie
off the rope so that it could be converted into a
lowering mechanism.

(And a reason for the Prusik here vs. using the
main rope is that SAR/caving/climbing kernmantle
ropes don't grip well to themselves --a Prohgrip/Blake's
would be your best hope, perhaps, but ... .)

Btw, sometimes one reads "frictionless hitch" for this,
and the confusion is captured nicely, now, in OnRope1.com's
MythBuster entry for this structure (in which it is argued
that only 2 wraps are needed) : both terms are (conf)used!

Myth #4: A High Strength Tie-off (Frictionless Hitch) needs 3 wraps around the anchor.

Truth: It often only needs two wraps around the anchor.
If properly named, it would be called "the tension-full hitch" instead of "the tensionless hitch".

--dl*
====

[Bob Thrun]

Both your 4wrapsPrusik and 2wrapsPrusik were tied with three wraps.

[Dan_Lehman]

Both your 4wrapsPrusik and 2wrapsPrusik were tied with three wraps.

Good job, Agent_Smith : on average, you nailed it!

               

[DerekSmith]

Would like to obtain opinions for a name change for the so-called 'tensionless hitch'.

I've never personally liked that name - and in my view the name is misleading as there is indeed tension and friction at play.

The principle of this type of hitch is well understood via the 'Capstan equation' (google for a mathematical treatment).
...snip

Mark

Hi Mark,

I have to agree totally that this is a nonsense name for the hitch, it is calling it exactly what it isn't, while in reality, it is exactly as Dan has pointed out from the OnRope1.com site, it is the 'High Strength Tie Off' or '100% hitch' or Full Strength Hitch'.

However, whatever name it 'should' be called, I believe that it equally should not be called a Capstan Hitch, because I understand that name is already in use for the AKA Lightermans / Tugboat hitch.

The USP of this hitch is that it is lossless with regards to strength (because there are no knots involved bearing upon the loaded line) and also that it can tollerate a variable load both in magnitude and direction (certainly within a solid angle of a circular radian).

This raises the fact that the 'end' should have no load bearing impact upon the loaded line at all - it should not grip it, pinch it nor deflect it in any way, otherwise it impinges upon the 100% strength which can only be achieved when the loaded line is free from any restraining force.  To that end, the Prusik termination destroys its functionality as a 'so called' 'Tenionless Hitch' - you have applied a fixing which utilises friction to impart a force and a deflection on the loaded line if it is moved in one particular quadrant of the solid angle.  I don't know what this new hitch would be called but it cannot be the 'Tentionless' nor even the 100% Strength shitch.  May I ask what USP you saw this addition bringing to the knot?

On a point of humour, I couldn't help but raise a smile at the construction displayed on the OnRope1.com site - vis -



Note the fig 8 and the bina to attach the dead end to the loaded line - it nicely prevents any load being transmitted to the loaded line, but what a waste of resources when they go on so much about resource use.  Far more frugal would have been to tuck a bight of the dead end behind the turns and thread the dead end through the bight before drawing it tight to hold the loops in place...

Derek

[Bob Thrun]

The name "Frictionless Hitch" is just wrong.  It depends on friction between the rope and whatever the rope is wrapped around.

[DerekSmith]

The name "Frictionless Hitch" is just wrong.  It depends on friction between the rope and whatever the rope is wrapped around.

Indeed Bob,

A 'frictionless hitch' is the very antithesis of all of knotting.  Without friction, none of our knots could function, in fact, without friction most cordage could not function.

Derek

[agent_smith]

Thanks Bob for your comment re the Prusik hitch!

Obviously its a 3 wrap prusik hitch...its just my naming convention that I happened to choose to distinguish the multitude of images that populate my computer hard drive.

Maybe I should have added a hyphen to separate the terms within the file name!

Mark

[SS369]

To give this another name is all well and good, but how do you go about getting rid of the previous name(s) as with many other knots that have a new name per week (yes exaggerated a bit) it seems?
The "tensionless" hitch is a neat name that conjures almost magical knotting in one's mind and though I understand what the name implies, my opinion is that it isn't a great name, except for the novelty of the name.

I have always called this a multi-wrap tie off to the people I show it to when we go climbing/rappelling. My method of tying is a bit different than what has been shown previously in this thread.
I will wrap the rope around the post, tree, etc., two or three times, then do a timber hitch finish with as many twirls as seems prudent in consideration of the objects girth. More twirls for larger objects. Generally, if the twists/twirls go more than half way around it will be a sound tie off. Give the WE a hard tug and it is secured.

I developed this for my self originally while pulling trees after felling because it is so easy,never jams and always holds, even with rope breaking jerks. Dressed and tightened correctly it stays secure through many a flogging flailing.

SS

[Bob Thrun]

Note the fig 8 and the bina to attach the dead end to the loaded line - it nicely prevents any load being transmitted to the loaded line, but what a waste of resources when they go on so much about resource use.  Far more frugal would have been to tuck a bight of the dead end behind the turns and thread the dead end through the bight before drawing it tight to hold the loops in place...

Cavers often tie off their rope and go down a  pit, leaving the rope unattended.  The nicely finished knot and carabiner lets passersby know that the rope was placed for a reason by someone who knows what he is doing.  We often tie the rope around the base of a tree.  In such a situation, we could wrap the rope around the tree six times without any finishing knot, carabiner, or half hitches.  Just let the free end of the rope lay on the ground.  I would be afraid of someone thinking it was an abandoned rope, or being helpful by tying the rope "better".

I use the multi-wrap or tensionless hitch (or whatever we want to call it) because a person on rope can be lowered in an emergency.  Another rope might have to be tied on.  The often-touted "full strength of the rope" is irrelevant in almost all situations.