Lets talk about rope....

[Pinner]

I still just dont see how creep affects a line for daysailing, yet vectran is always recommended for upwind halyards

since elastic elongation is less for dyneema than vectran, why wouldn't all dinghy sailors use it?

for example- you would see nearly similar stretch characteristics from 1/8" sk90 as 3/16" vectran b/c the run is short on a dinghy jib halyard- say 15-25ft

am I way off base here?

 

[russell_miller]

I will perform the required tests and do a write-up so that you all don't think I'm crazy. My goal will be to have it done by June 1.

Pinner

Creep doesn't factor into materials on sailboats except for maybe standing rigging that is left under tension for a long time (years) UHMWPE has a low yield stress, so it changes from an elastic elongation regime to plastic deformation before other materials used in lines would. So, if the load will never exceed the yield stress, UHMWPE lines are a better choice, but since the yield stress isn't published, its a knowledge you have to gain through trial and error.

You aren't way off base, but when you need a line to be a given length, you need it to be that length.

 

[BillOSail]

This seems like a good thread to post this question. How do you splice 1/4" shock cord to 1/4" Spectra? Can you send the shock cord up the center of the spectra and sew and whip it? (If so how long does it need to go in) The line in question will be used on the uphaul/downhaul for my C.B. on a 505. I'm using spectra because it's what I have.

 

[sloansailing]

I will perform the required tests and do a write-up so that you all don't think I'm crazy. My goal will be to have it done by June 1.

Cool I'd be interested in seeing what you come up with and what tests you perform.

 

[russell_miller]

This seems like a good thread to post this question. How do you splice 1/4" shock cord to 1/4" Spectra? Can you send the shock cord up the center of the spectra and sew and whip it? (If so how long does it need to go in) The line in question will be used on the uphaul/downhaul for my C.B. on a 505. I'm using spectra because it's what I have.

Not a really a critical application for line choice Bill. I just tied the line to the takeup.

 

[BillOSail]

This seems like a good thread to post this question. How do you splice 1/4" shock cord to 1/4" Spectra? Can you send the shock cord up the center of the spectra and sew and whip it? (If so how long does it need to go in) The line in question will be used on the uphaul/downhaul for my C.B. on a 505. I'm using spectra because it's what I have.

Not a really a critical application for line choice Bill. I just tied the line to the takeup.

I had some shorts that matched the color of my boat so.... that's what I used, thanks for the answer, I tied it too, for now.

 

[notallthere]

Sorry that story was so long, but it goes to show...terms like stretch, constructional stretch, creep (when used in the manor that sailors use it) are all bullshit and don't tell you a thing about the material.

If you are making a technical materials decision, you have got to suck it up and get technical yourself.

Sorry man but I have to disagree, I think that there is enough information available to make an educated decision about lines today. After reading what you wrote about your friend, the bottom line is that even given all of the information available today, your friend still didn't make an educated decision otherwise he wouldn't have picked a line for a headstay that experiences creep.

The 505 used what 1/8" 1x7 wire headstay? Well while 1/8" dyneema may have higher load ratings, etc... you have to go up a size when going from wire to rope in order to get the same working affect as the wire otherwise you will experience a LOT of movement.

Yacht Rigging has never been and never will be an exact science.

great, so WHAT fiber/ diameter would you use?