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-   -   Knots in the rope? (http://www.chiefdelphi.com/forums/showthread.php?t=153142)

GeeTwo 07-01-2017 22:55

Re: Knots in the rope?
 
On splices...

As I read it, an "end cap splice" of up to four inches in length would probably be OK (though that would be rather short for 1" line).
Slicing the rope along its length to another rope would require the splice to still be no larger than 1" in diameter (not too difficult if the line is 5/8" or smaller) would still be "braided" and allowed.

Splicing a loop into the end of the line (unless it were very short and could all fit in 4") would not be a knot and would not be allowed. (Say the last part three times fast.)

[Usual caveat that this is my opinion, not a Q&A answer.]

Kevin Sevcik 07-01-2017 23:24

Re: Knots in the rope?
 
Quote:

Originally Posted by EricH (Post 1626693)
But they can be very stiff...

Better not make it too stiff for too long a distance:
Quote:

Originally Posted by I04-D Bluebox
Flexible means that if the ROPE is held at any point, it should not extend more than 12” above the point where it is held. ROPES are meant to be pulled, not pushed.


LEGOlas798 07-01-2017 23:54

Re: Knots in the rope?
 
I can't help but think about this quote in rule I04, section D:

"consist entirely of flexible, non-metallic fibers twisted, tied, woven, or braided together except for the last 4 in. (~10 cm) of each end which may be whipped, fused, covered in heat shrink or tape, or dipped in a coating material to prevent fraying"

Does anyone know of a "coating material" that can be magnetized? Just an idea.

The Swag Muffin 08-01-2017 00:03

Re: Knots in the rope?
 
Could you use a mettle crimp at the end of a rope to keep it from fraying.

"Consist entirely of flexible, non-metallic fibers twisted, tied, woven, or braided together except for the last 4 in. (~10 cm) of each end which may be whipped, fused, coveredin heat shrink or tape, or dipped in a coating material to prevent fraying."

Would mettle all so be excepted for the last 4 inches?

Kevin Sevcik 08-01-2017 00:08

Re: Knots in the rope?
 
Quote:

Originally Posted by LEGOlas798 (Post 1626944)
Does anyone know of a "coating material" that can be magnetized? Just an idea.

You can get magnetic paint/primer, but I suspect the GDC is going to shoot that one down on Q&A.
Quote:

Originally Posted by The Swag Muffin (Post 1626952)
"Consist entirely of flexible, non-metallic fibers twisted, tied, woven, or braided together except for the last 4 in. (~10 cm) of each end which may be whipped, fused, coveredin heat shrink or tape, or dipped in a coating material to prevent fraying."

Would mettle all so be excepted for the last 4 inches?

Do you see "crimped metal ferrule" in that list of end treatments? If you HAVE to have something metallic there, I think currently your options are magnetic paint or whipping it with steel wire/cable. I seriously wouldn't get my hopes up about that, though. I think that's likely to get shot down about a day after the Q&A opens.

Back on the knots subject, in case anyone hasn't done the math, it looks like the davit has about 22" of steel guide below where the attachment knot should go. So a knot in your rope should be about 7" below the steel channel of the davit. Not sure how far below the touchpad that puts you, but it's definitely close. I'm assuming y'all are thinking of regularly spaced knots and a notched pulley?

Cothron Theiss 08-01-2017 00:11

Re: Knots in the rope?
 
I want to add to this discussion that any of the modifications you can make to the last 4" of the rope must be in order to prevent fraying. This kind of thing will be inspected on a one by one basis, and if your rope has anything that the inspector deems not for the purpose of preventing fraying, they shouldn't allow it to pass inspection.

Cothron Theiss 08-01-2017 00:17

Re: Knots in the rope?
 
Quote:

Originally Posted by The Swag Muffin (Post 1626952)
Could you use a mettle crimp at the end of a rope to keep it from fraying.

"Consist entirely of flexible, non-metallic fibers twisted, tied, woven, or braided together except for the last 4 in. (~10 cm) of each end which may be whipped, fused, coveredin heat shrink or tape, or dipped in a coating material to prevent fraying."

Would mettle all so be excepted for the last 4 inches?

The way I read the rules, I think that no metal of any kind will be allowed on any part of the rope. I think the non-metallic bit is meant to describe ALL parts of the rope. But don't take my word for it. This is probably a question for the Q&A. A team could decide to dip their ropes in molten aluminum or iron for some reason.

cadandcookies 08-01-2017 01:30

Re: Knots in the rope?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1626960)
You can get magnetic paint/primer, but I suspect the GDC is going to shoot that one down on Q&A.
Do you see "crimped metal ferrule" in that list of end treatments? If you HAVE to have something metallic there, I think currently your options are magnetic paint or whipping it with steel wire/cable. I seriously wouldn't get my hopes up about that, though. I think that's likely to get shot down about a day after the Q&A opens.

Back on the knots subject, in case anyone hasn't done the math, it looks like the davit has about 22" of steel guide below where the attachment knot should go. So a knot in your rope should be about 7" below the steel channel of the davit. Not sure how far below the touchpad that puts you, but it's definitely close. I'm assuming y'all are thinking of regularly spaced knots and a notched pulley?

From the knots and loops school of thought, Ri3D 'Snow Problem is attempting a climber that will essentially act as a winch on a rope with a loop at the end, using rotating pegs and a cam cleat. We should have a video of our prototype on Monday (it's linked to our intake, and is basically just an interesting concept that isn't much of a risk for us if it doesn't work out).

Kevin Sevcik 08-01-2017 10:26

Re: Knots in the rope?
 
Quote:

Originally Posted by cadandcookies (Post 1627017)
From the knots and loops school of thought, Ri3D 'Snow Problem is attempting a climber that will essentially act as a winch on a rope with a loop at the end, using rotating pegs and a cam cleat. We should have a video of our prototype on Monday (it's linked to our intake, and is basically just an interesting concept that isn't much of a risk for us if it doesn't work out).

I think that'll be a pretty common idea, yeah. Don't kill yourselves getting the cam cleat working though. If you can lift the whole way without it, your lift is good enough, since scoring is at the instant of T=0. If you've had the touchpad triggered for >1s before T=0, then you're good.

The cam cleat would save some battery since it'd hold you in place passively, and it'd give you a 1s margin, since triggering the pad at T=0 and maintaining for 1s also scores. But staying up there after T=0 definitely isn't a requirement this year.

cadandcookies 08-01-2017 10:46

Re: Knots in the rope?
 
Quote:

Originally Posted by Kevin Sevcik (Post 1627120)
I think that'll be a pretty common idea, yeah. Don't kill yourselves getting the cam cleat working though. If you can lift the whole way without it, your lift is good enough, since scoring is at the instant of T=0. If you've had the touchpad triggered for >1s before T=0, then you're good.

The cam cleat would save some battery since it'd hold you in place passively, and it'd give you a 1s margin, since triggering the pad at T=0 and maintaining for 1s also scores. But staying up there after T=0 definitely isn't a requirement this year.

The entire plan regarding our climber is to not kill ourselves over getting it working-- we figure that whether we fail miserably or succeed wildly, or anywhere in between, the community learns something, which is why we're doing Ri3D in the first place.

1247Robotics 08-01-2017 10:47

Re: Knots in the rope?
 
Quote:

Originally Posted by markmcgary (Post 1626652)
We've already found a vendor for retroreflective rope.

I didn't see any rule regarding how legal this was. It would be great if it was legal since we are hoping to leverage vision tracking this year.

Tottanka 09-01-2017 15:44

Re: Knots in the rope?
 
Regarding knots in the loop, are you allowed to make them in the provided rope, and not have it count as the custom rope for the alliance?
Any reference for an anwer?

Cothron Theiss 09-01-2017 15:49

Re: Knots in the rope?
 
Quote:

Originally Posted by Tottanka (Post 1628069)
Regarding knots in the loop, are you allowed to make them in the provided rope, and not have it count as the custom rope for the alliance?
Any reference for an anwer?

I don't think there's a rule explicitly saying you can't, but your event staff will quickly come to hate you. Also, they could cite G02, specifically example J.

Ari423 09-01-2017 16:04

Re: Knots in the rope?
 
Quote:

Originally Posted by Tottanka (Post 1628069)
Regarding knots in the loop, are you allowed to make them in the provided rope, and not have it count as the custom rope for the alliance?
Any reference for an anwer?

No rule to reference, but from a practical standpoint I expect the answer is no. Your whole rope, including knots must be less than 1" wide. If you put knots in the provided rope without getting it inspected*, there is no way to ensure that your rope follows that rule.


*on-field inspections are not allowed and you can't remove the provided ropes from the field

engunneer 09-01-2017 16:19

Re: Knots in the rope?
 
Quote:

Originally Posted by Tottanka (Post 1628069)
Regarding knots in the loop, are you allowed to make them in the provided rope, and not have it count as the custom rope for the alliance?
Any reference for an anwer?

I don't think the alliance is limited to a single custom rope anyway. I think each team is limited to a single custom rope.

I also agree that the field's rope cannot be knotted, as it is not inspectable.


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