The jib halyard for my G-Cat has some burrs and needs replacement. A friend suggested as an option to wire, consider one of these new low stretch lines either 1/4 or 3/16ths. Since I don't race anymore and these high tech lines hardly stretch at all, is this a viable alternative? How about knot retention and longevity when exposed to prolonged UV exposure?
3mm single braid Dyneema is more than enough.
Dyneema has excellent uv properties. It's slippery so knots don't hold well. There's a whole set of different knots you can use with dyneema for good hold. They are easy to tie, mostly simple knots - trucker's hitch.
What about dacron that is cored with dyneema? Would that help the knot retention issue?
yup
i use 3mm robline dingy control line. it survives years of uv and non-cleated use.
it isn't optimal in cleats. (and my cats are under tarp but i have used this line for years and so do many)
MN3
Why knots? Single braid Dyneema is easy, even för a novice, to splice.
Edited by revintage on Sep 08, 2019 - 12:20 PM.
You can use Dyneema or something equivalent. For this boat, a bowline will be sufficient. I have used 7/64" tech-12 on my Prindle 19 with a large jib and never had an issue. One thing to check and consider are the blocks involved with the halyard. Take some toilet paper and rub the sheaves. You are looking for burrs or sharp points with the block. Many times a wire halyard will build grooves in the sheave and these grooves will tear up a synthetic line. Don't get too involved in the line type. If you are not racing then it really doesn't matter how high tech the line gets; it's just money...
Keep it simple, keep it affordable.
If you tie a bowline in any of the 12-strand dyneema lines, it will slip under pressure. However, if you put a couple of drops of splicing fluid (super glue) on the knot, it will hold...
I've not noticed that much Mike. I use an extra long tail and tend to loop the line through the ring prior to tying so the line is taking the load, not so much the knot.
mikekrantz wrote: If you tie a bowline in any of the 12-strand dyneema lines, it will slip under pressure. However, if you put a couple of drops of splicing fluid (super glue) on the knot, it will hold...
Good idea.. I have never had a bowline in Dyneema slip out. I guess I've been lucky. To splice the small stuff, I use the needle and taper it before I splice.
mikekrantz wrote: If you tie a bowline in any of the 12-strand dyneema lines, it will slip under pressure. However, if you put a couple of drops of splicing fluid (super glue) on the knot, it will hold...
Good idea.. I have never had a bowline in Dyneema slip out. I guess I've been lucky. To splice the small stuff, I use the needle and taper it before I splice.
Links below should work now.
Videos are recorded in slow motion, so use your slider bar to fast forward to the breaking point.
Edited by mikekrantz on Sep 19, 2019 - 09:51 AM.
OK, just to circle back to this.
I took Marlow D12 Max 99 - 2.5mm with a rated Avg Breakload @ 1,100kg / 2,425lbs
I made up 4 samples and videotaped them on the "Punisher"
Bowline only tied to the shackle failed at 408lbs - https://vimeo.com/360882574
Bowline with Superglue failed at 563lbs - https://vimeo.com/360882767
Bowline with a wrap failed at 648lbs - https://vimeo.com/360883063
Brummel eye splice with tapered bury failed at 2,091 lbs - https://vimeo.com/360883347
Edited by mikekrantz on Sep 19, 2019 - 09:50 AM.
"Sorry, we couldn’t find that page"
none of those links work for me
MN3
none of those links work for me
Try tomorrow - it usually takes vimeo a couple of hours to upload them to their servers...
-Mike
No question using a knot is no where near as strong as a splice. To learn more about this I would suggest a google search on "seaworthy lass". I have learned more from her about what to do with my dyneema than you can imagine. Just as an aside her instructions on soft shackles is a must.
http://forums.sailinganarchy.com/index.php?/topic/185714-introducing-the-crown-jewels-soft-shackle/
Try tomorrow - it usually takes vimeo a couple of hours to upload them to their servers...
ok
MN3
videos work today
amazing how much stronger the brummel is
i still don't really know what sam meant "Bowline with a wrap "
can someone explain please - thanks!
and thanks Mike for the videos and data
Edited by MN3 on Sep 19, 2019 - 11:25 AM.
MN3
When you're tying the bowline, instead of passing the line over the shackle pin and back to complete the knot. Make a wrap around the shackle pin and back to complete the knot.
mikekrantz wrote: When you're tying the bowline, instead of passing the line over the shackle pin and back to complete the knot. Make a wrap around the shackle pin and back to complete the knot.
Gotcha - that's what i thought but wasn't sure
curious how strong a regular eye splice is compared to the brummel
MN3
Strength wise, about the same. However, if you load and unload the splice over time, the straight bury can work itself out. I've seen it happen quite often on trap lines. Usually resulting in a broken tiller extension...
Strength wise, about the same. However, if you load and unload the splice over time, the straight bury can work itself out. I've seen it happen quite often on trap lines. Usually resulting in a broken tiller extension...
Thanks Mike!
I typically put a lock stitch in all my eye splices (as the samson lessons say must be used to prevent failure - https://www.youtube.com/watch?v=eHUQHpyG2wA )
i have yet to have an eye splice fail after it being lock stitched
I also learned long ago when i fall overboard for any reason (broken trapwire, overly slippery sunscreen on legs that have gone wrong, etc) .. hold the mainsheet (for dear life) but dump the tiller extension (so far i have about a 50/50track record with remembering to dump the stick)
MN3