Best Stopper Knots for Team Supplied Knots

[mrnoble]

Major props to OP for creating this post. We all needed this.

[Cothron Theiss]

Originally Posted by GeeTwo

Why? While it was not invented as a stopper knot (more of a starter knot), and uses a lot of line, it's not terribly difficult to tie; I learned it in an hour or so. If you use a single overhand knot as the core, you can nest them, beginning with a "two loop" for the first layer and adding about two loops per layer. For use in the davit fingers with smaller lines, tt also distributes the force of the support quite well.

Originally Posted by JesseK

My team doesn't plan to use any knots in the rope for climbing. However, given the ~6mm rope we're testing now we'll need a good DAVIT knot. Are there tricks to making any of the listed knots bigger?

I'll try and answer both of your questions at the same time, because they both concern the same knot.

The Monkey's Fist is often touted as the largest stopper knot, which may very well be true. But I really don't like using the Monkey's Fist without a solid core, like a marble or something. And using a small knot like an overhand or an Ashley Stopper as the core feels like a messy solution to me. But it may end up being the only feasible option for very small diameters of rope. If this ends up being the case, adjusting the knot will become a chore, but that may just be the way it is.


Stepping away from the solid ground of well known stopper knots, you may be able to use some sort of follow through looping stopper knot. Lots of end-loop are basically a stopper knot that has the tail following through the knot to form the loop. I know that's not a good explanation, so check out the Figure Eight follow through for a prime example of what I mean. I wonder if the same concept can be applied to stopper knots to create larger stopper knots. So what I'm thinking is that you'd create a loose Ashley stopper, then reroute the tail (NOT the standing end) through the knot so that the tail is coming out next to the standing end. You'd then have a loop coming out where the tail usually exits the knot. I've no idea if something like this would work or not. I don't have nay rope on hand at the moment, so I'm kind of flying blind if it comes to inventing a larger stopper knot.

[Jonah303]

My team is planning on using a monkey fist knot as the stopper on the end of our rope. If you use a monkey fist as the core of another monkey fist and tie it really tight, It is very strong.

[Gary Bonner]

I am not thrilled about the idea of suspending our robot by a stopper knot, especially with a 1" square retaining opening. There are much more secure ways of fixing a rope to the davit. The blue box 12" rule makes even things less secure, as larger line, with which you could tie larger knots, is more likely to fail the test. I doubt that the line in the field tour videos would pass the test.

Complaints aside, some other knots to consider are those used in soft shackles, such as the diamond knot and the button knot which can be seen here.

[s_forbes]

I wonder if this would be a good approach if you're using a really small diameter rope:

[Cothron Theiss]

Originally Posted by Jonah303

My team is planning on using a monkey fist knot as the stopper on the end of our rope. If you use a monkey fist as the core of another monkey fist and tie it really tight, It is very strong.

The more I think about it, the more I think that I may have to amend my earlier statements warning against monkey's fists. They may be the best, if not only way for teams using very small diameters of cord to get a stopper knot large enough. I imagine a team using standard solid core paracord will need to use several successive monkey's fists to get to the size they need. When I get a chance and get some rope, I'll try tying this and see what happens.

Originally Posted by Gary Bonner

I am not thrilled about the idea of suspending our robot by a stopper knot, especially with a 1" square retaining opening. There are much more secure ways of fixing a rope to the davit. The blue box 12" rule makes even things less secure, as larger line, with which you could tie larger knots, is more likely to fail the test. I doubt that the line in the field tour videos would pass the test.

Complaints aside, some other knots to consider are those used in soft shackles, such as the diamond knot and the button knot which can be seen here.

I agree. Having a peg or hook for a loop to go onto would have been a MUCH more secure way to attach the Ropes.

I'd been avoiding all the knots and shackles used in splicing because I figure many teams won't be using a splicable rope, but if teams want to go down the splicing path, that does open up a lot of really great options. Do you know of a way to make single strand variants of the diamond and button knots?

[Cothron Theiss]

Ok, so I took a shot at the double monkey fist. (Successive monkey fist? Fist in a fist? I'm not sure what to call this.) The cord is gutted 550 paracord, which is ~3mm in diameter. While I would never use this cord itself to hold anything of value, true 550 paracord could hold a robot. (The 550 comes from its static load rating, 550 lbs.) To make this knot, I put an Ashley Stopper at the end of the line, then tied a monkey fist around the Ashley Stopper. This first monkey fist had 3 wraps per side. Then, I tied a second monkey fist around the first one. The second monkey fist had 6 wraps per side.



I am pleasantly surprised with the result. I actually made a few small mistakes on the first monkey first, resulting in a less spherical knot than I would like. After tying the first monkey fist, I wasn't very pleased from how it was turning out. even aside from my errors, it wasn't looking good as a robust stopper knot. But after the second monkey fist, I felt much better about it. The amount of length taken up by this knot is astounding, but considering that the goal is a sphere at least 9 times the diameter of the rope making up the knot, it's not too surprising.

Tomorrow, I will try it again. I'll do a better job on the initial core (I might try a different knot for the initial core.), I'll make sure to rectify any errors on the first monkey fist, and I'll switch to only 5 wraps on the second monkey fist. Currently, it's quite loose around the corners and there's a bit of folding in the sides, which are both signs of there being one too many stands per side. Eventually I'd like to buy some real paracord and try out this knot on something that actually resembles the DAVIT, but until then, I can only recommend that teams consider this knot as a potential option and try it out themselves.

[Jonah303]

I've already done a triple layer monkeys fist. After that many layers and wraps, you can get a very substantial knot. What I've found, is that for each successive layer you need to add two more wraps. (Ex 3,5,7) That is so you won't have wraps overlapping each other. I've also trimmed and fused the two extra ropes that stick out when you finish each layer (that is not the first fist). I've e only kept the strand that sticks out when you finish the first monkey fist. If you do it like that, the rope that the robot will be pulling on is deep within the knot.

[chrisrin]

Is it viable to use a section of thick rope with an overhand knot at the top joined to a very thin rope (like 550 paracord) that hangs down to interface with the robot? Not joined by splice but using strong loop knots?

[JesseK]

Originally Posted by s_forbes

I wonder if this would be a good approach if you're using a really small diameter rope:

That is an excellent choice for any team called the Robocats.

[GeeTwo]

Originally Posted by chrisrin

Is it viable to use a section of thick rope with an overhand knot at the top joined to a very thin rope (like 550 paracord) that hangs down to interface with the robot? Not joined by splice but using strong loop knots?

Certainly seems legal now. (after Q22 and Q89)

Per IO4-F, there is a 29" minimum distance between the davit knot and the first knot in the rope, presumably to put it below the davit channel. This This means that your thin rope would have to begin several inches below the touchpad. Not a show stopper, but something you'd have to design for.

[Gary Bonner]

Originally Posted by Cothron Theiss

Do you know of a way to make single strand variants of the diamond and button knots?

My initial thought was essentially to splice a loop and then cut the end of the loop, resulting in a "Y" at the end of the line. However, I'm not sure the splice bury would pass the 12" rule.

I'd be interested to hear how the monkey fists perform under a 150# load.

[Daniel_LaFleur]

Originally Posted by Gary Bonner

My initial thought was essentially to splice a loop and then cut the end of the loop, resulting in a "Y" at the end of the line. However, I'm not sure the splice bury would pass the 12" rule.

I'd be interested to hear how the monkey fists perform under a 150# load.

I'm more interested in a much heavier load when the robot winch keeps turning after the robot has hit the davit

[JesseK]

If we do exactly a 1" knot, is there anything in the DAVIT's construction to prevent the knot from off-centering and falling through? If knot, will thinner ropes need a knot of up to 2" in diameter?

[Mark McLeod]

From the field drawings (GE-17081) it appears that the slot holding the top knot is 1.125" wide and 1.675" tall (to center of holding pin, so a tiny bit less).
Our holding knot had better not be compressible to pull through that.