how do you stretch HM line? :: Catamaran Sailboats at TheBeachcats.com

how do you stretch HM line?

MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: Apr 06, 2024

Posts: 7088
Posted: Aug 09, 2019 - 11:54 AM

Looking for info, methods, etc on how to best "pre" strech dynema to reduce lifetime streching (not creep)

I know Sam posted some data on it, but my searches have 't found it.

thanks!
pknapp66

Rank: Mate

Registered: May 09, 2009

Last visit: May 15, 2023

Posts: 684
Posted: Aug 09, 2019 - 12:23 PM

Like this of course

https://www.youtube.com/watch?v=LR7HcsDY3kQ

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Pete Knapp
Schodack landing,NY
Goodall Viper,AHPC Viper,Nacra I20
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: Apr 06, 2024

Posts: 7088
Posted: Aug 09, 2019 - 12:29 PM

Thanks Pete:
He looks like a real pro!

I love this comment: "What I've learned watching your video's is that boating isn't for me. Thanks for saving me a fortune!"

I probably wont be doing this method
mikekrantz

Rank: Lubber

Registered: Mar 06, 2006

Last visit: Aug 23, 2023

Posts: 99
Posted: Aug 09, 2019 - 03:08 PM

After I splice the line, I use a hydraulic ram and a load cell to run it up to 50% of it's breaking strength and hold it there for 30 mins or so. That resets the fibers that are loosened up during the splicing process.

The pre-stretched dyneema that I purchase has been run through a heat/steam die process to reduce the diameter and align the fibers. This is how all of the "pre-stretched" dyneema that I use is created.

-Mike
MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: Apr 06, 2024

Posts: 7088
Posted: Aug 09, 2019 - 03:21 PM

Thanks Mike,
can i borrow your ram?
mikekrantz

Rank: Lubber

Registered: Mar 06, 2006

Last visit: Aug 23, 2023

Posts: 99
Posted: Aug 09, 2019 - 05:29 PM

You're going to need a big truck. It's attached to a 30' I-beam.

If I can figure out how to edit a video clip, I'll post one of finding out what the breaking point is on a soft shackle

it's more fun to break stuff than just stretching things.
cholley12

Rank: Mate

Registered: Feb 28, 2018

Last visit: Feb 13, 2023

Posts: 145
Posted: Aug 10, 2019 - 09:05 AM

I stretch it between my truck and wife's car tow points using my main sheet system. I'm figuring that I can put near 1k lbs into it. On smaller applications under 10 ft and under 1/8 line I stretch it on my bow string jig

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Captain Chris Holley
Fulshear, TX
'87 Prindle 19 "¡Hijole!"
'74 sunfish "1fish"
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