Contact   Imprint   Advertising   Guidelines

Does a knot in the kite line really half its strength?

Forum for kitesurfers
User avatar
ChristoffM
Medium Poster
Posts: 196
Joined: Tue Jul 19, 2011 5:26 pm
Local Beach: Langebaan and Cape Town.
Favorite Beaches: Anywhere in the Cape, South Africa.
Style: Hydrofoils! (And surf and old school)
Gear: Cape Town Foilboard and Spotz hydrofoils.
Any kite that can keep up with the hydrofoils.
Brand Affiliation: Cape Town Foilboards
Location: Langebaan (Cape Town)
Has thanked: 0
Been thanked: 0
Contact:

Re: Does a knot in the kite line really half its strength?

Postby ChristoffM » Fri Jun 22, 2012 4:47 pm

Thanks for the WD40 idea! Sometimes one can damage the lines trying to get a tight knot out. That is definitely some good advice! :thumb:

User avatar
Bigdog
Very Frequent Poster
Posts: 573
Joined: Mon Jul 26, 2004 6:50 pm
Local Beach: Wolfe Island
Style: Old and grey surfer dude style
Gear: Core xr5 and windego boards
Brand Affiliation: None
Location: Wolfe Island Canada
Has thanked: 0
Been thanked: 0
Contact:

Re: Does a knot in the kite line really half its strength?

Postby Bigdog » Fri Jun 22, 2012 5:06 pm

I would be a little concerned that the solvent in the wd40 might eat into the spectra and degrade it somewhat.

User avatar
jakemoore
Very Frequent Poster
Posts: 2095
Joined: Tue Jan 20, 2004 3:59 am
Gear: Foil and 1strut kites.
Brand Affiliation: None
Location: Oleander
Has thanked: 70 times
Been thanked: 149 times
Contact:

Re: Does a knot in the kite line really half its strength?

Postby jakemoore » Sat Jun 23, 2012 3:26 am

http://www.mooring-solutions.com/About_ ... y__87.html

I wouldn't worry about the solvent at all, but I would worry about the line picking up dirt and ending up looking like an old bike chain.

SOLO FLIGHT 2012
Rare Poster
Posts: 23
Joined: Tue Jan 10, 2012 11:42 am
Brand Affiliation: None
Has thanked: 0
Been thanked: 0

Re: Does a knot in the kite line really half its strength?

Postby SOLO FLIGHT 2012 » Sat Jun 23, 2012 2:18 pm

Dyneema is HDPE thats polyethylene fibre, basically shopping bag plastic,the stuff is not prone to reacting with solvents they use it to make containers for nearly anything.
However my lines are sacred ,so I would always rinse the WD40 spot with lukewarm water and some dishwashing soap.

User avatar
RogueKiteboarding
Rare Poster
Posts: 34
Joined: Tue Jun 12, 2012 4:20 am
Brand Affiliation: www.RogueKiteboarding.com
Location: Florida
Has thanked: 0
Been thanked: 0
Contact:

Re: Does a knot in the kite line really half its strength?

Postby RogueKiteboarding » Sun Jun 24, 2012 6:27 am

mogthedog wrote:I got a knot in one of my back lines and have been told by a dull chum that a knot in the line will half the strength of the line.

Is this true or is my chum being dull??
Hello. If your lines continue to get tangled and you'd like to prevent that by keeping them organized; you might want to look into a line winder. It should help to prevent your lines getting knots.

We're currently running a contest for a free line organizer.
Hope this is useful for you :bye:


User avatar
PugetSoundKiter
Medium Poster
Posts: 189
Joined: Sat Feb 20, 2016 5:53 pm
Style: Wake TT, Strapless Surfboard, Landboard
Gear: Cabrinha, Ocean Rodeo, Slingshot, Naish, North, Pansh, Ozone, HQ, Peter Lynn
Brand Affiliation: None
Has thanked: 25 times
Been thanked: 20 times

Re: Does a knot in the kite line really half its strength?

Postby PugetSoundKiter » Sat Jan 04, 2020 1:04 am

:advise:
Researchers were able to identify general "counting rules," or characteristics that determine a knot's stability. Basically, a knot is stronger if it has more strand crossings, as well as more "twist fluctuations," changes in the direction of rotation from one strand segment to another.

For instance, if a fiber segment is rotated to the left at one crossing and rotated to the right at a neighboring crossing as a knot is pulled tight, this creates a twist fluctuation and thus opposing friction, which adds stability to a knot. If, however, the segment is rotated in the same direction at two neighboring crossing, there is no twist fluctuation, and the strand is more likely to rotate and slip, producing a weaker knot.

A knot can be made stronger if it has more "circulations," which they define as a region in a knot where two parallel strands loop against each other in opposite directions, like a circular flow.

By taking into account these simple counting rules, the team was able to explain why a reef knot, for instance, is stronger than a granny knot. While the two are almost identical, the reef knot has a higher number of twist fluctuations, making it a more stable configuration. Likewise, the zeppelin knot, because of its slightly higher circulations and twist fluctuations, is stronger, though possibly harder to untie, than the Alpine butterfly, a knot that is commonly used in climbing.

https://science.sciencemag.org/content/367/6473/71
Topological mechanics of knots and tangles, Science 03 Jan 2020: Vol. 367, Issue 6473, pp. 71-75


In 2018 the Rockwell International Career Development Associate Professor at MIT, Mathias Kolle’s group engineered stretchable fibers that change color in response to strain or pressure. The researchers showed that when they pulled on a fiber, its hue changed from one color of the rainbow to another, particularly in areas that experienced the greatest stress or pressure.

http://news.mit.edu/2020/model-how-strong-knot-0102
math-knots-1.gif
math-knots-1.gif (4.74 MiB) Viewed 395 times
These users thanked the author PugetSoundKiter for the post (total 2):
nixmatters (Sat Jan 04, 2020 7:36 am) • Trent hink (Sat Jan 04, 2020 2:29 pm)
Rating: 13.33%

foilholio
Very Frequent Poster
Posts: 3429
Joined: Sun Aug 23, 2015 3:20 am
Local Beach: Ventura Beach
Favorite Beaches: Tarifa
Style: Airstyle
Gear: Foils
Brand Affiliation: None
Has thanked: 227 times
Been thanked: 144 times

Re: Does a knot in the kite line really half its strength?

Postby foilholio » Sat Jan 04, 2020 10:42 am

I remember reading a bit of an actually quite long paper on knots. The basic principle was the radius of certain bends and if they are tight in the right place they can cut the knot easier. It goes to the same principle that thinner lines could break easier with knots and they do. Dyneema is also quite slippery, which I think would effect knots and certainly effects splices, which need to be much longer than other materials for the same strength. You also have mixed materials, where line like dyneema can cut through other material like nylon, and kevlar is even worse.

The strongest line join is a splice, so to the degree a knot can emulate that it would. The principle is keep the load section long and straight and hold the outside with friction over a long length. Fishing has some very long complicated knots that would do that.

Hugh2
Very Frequent Poster
Posts: 933
Joined: Tue Oct 30, 2012 3:38 am
Kiting since: 2005
Weight: 190lb
Local Beach: Central Illinois
Favorite Beaches: Cape Hatteras and Cape Town
Style: freeride
Gear: Cabrinha Nomad 5.5, Best Cabo 6, Naish Pivot 6, 7, 9, 10 and 11, Cabrinha Vector 12
Long Ocean 136, Cyclone 138, Fone Surf 5'11", Naish Global 6'0", Cyclone 6’0”, Slingshot Hoverglide H5 foil and Alien Air 4' 6" and Converter boards
Brand Affiliation: None
Has thanked: 34 times
Been thanked: 105 times

Re: Does a knot in the kite line really half its strength?

Postby Hugh2 » Sat Jan 04, 2020 5:39 pm

No discussion of how to avoid knots in the first place. After developing a couple within the last 2m of my lines, I made a habit of running those last few meters one more time, individually, through my hands as I prepared to attach them to the kite. Have not had a knot in my lines for almost a decade now.

User avatar
BillyGoatGruff
Very Frequent Poster
Posts: 614
Joined: Wed Mar 15, 2006 9:22 pm
Local Beach: UK
Gear: Naish Torch's
Brand Affiliation: None
Has thanked: 3 times
Been thanked: 58 times

Re: Does a knot in the kite line really half its strength?

Postby BillyGoatGruff » Sat Jan 04, 2020 6:20 pm

Prevent knots by running your lines out every time.

If you get a knot soak it in pure washing up liquid, this lubricants the dyneema knot and has zero effect on dyneema. Then gently tap the knot with a wooden mallet on a hard flat surface while rotating the knot, the key is slowly and carefully and use a small wooden toothpick once it’s loosened up a bit.

evan
Very Frequent Poster
Posts: 609
Joined: Sat Jan 31, 2004 5:48 pm
Kiting since: 2002
Local Beach: Brouwersdam
Style: Hydrofoil - Big Air
Gear: Infexion bars
Brand Affiliation: Infexion
Has thanked: 8 times
Been thanked: 96 times
Contact:

Re: Does a knot in the kite line really half its strength?

Postby evan » Sat Jan 04, 2020 6:37 pm

Preventing knots?

How on earth do you guys get them in to begin with? Never happened in my 19 years of flying kites, just put that small bit of extra care when winding and unwinding your lines.

In my tests, knots reduces the strength of thin prestretched Dyneema lines up to 70% with simple overhand knots.


Return to “Kitesurfing”

Who is online

Users browsing this forum: Bing [Bot], Google [Bot], MeganFos and 110 guests