California-winter sailing in February (is it really winter when there's no 'hard water' to be seen?) netted me a broken link on my Ronstan 55 series jib blocks: https://www.ronstan.com/marine/orbitblock-instructions.asp

On closer spring-cleaning inspection, the opposite side was getting a bit ratty, as well, so last Saturday night, I pulled out some scrap 3mm SK-90 Dyneema and the splicing tools. More hours later than I care to think about, I threw in the towel and did two small loops with a square knot in each, with the tails whipped, lock-stitched, and then over-whipped. That got me out on the water Sunday... but "Knots, splices, stitching, etc. will generally have a lower Breaking Load than the rope itself."

I have had good success eye-splicing and also making soft shackles of this small line before, but I just could not get it to work on 3mm line in such a small loop. Larger hollow-braid expands more relative to its diameter, any tips on working with smaller splices... my commercial fids are too big for tight loops, and my home-built ones aren't much smaller!

I will probably just throw my purse at the issue and have APS send me a pair of $10 Ronstan replacements (I'll set the square-knots aside as emergency spares), but I'd really like to be able to buid these on my own. Any tips or suggestions?

Randii

Square knot on small-diameter dyneema is not reliable.

I have the harken soft-attach shackles, and tie them up with a fisherman's knot. Double fisherman's knot better, if you can work it through.

Splicing these thin lines on such short lengths does not lead to sanity

I like the brion toss tools
if you know how they work you could just use wire

question: how do you use these blocks as a jib block? they dont cleat?

Agreed on the shortage of security/sanity, but with four strands connection the Orbit block and the eye-slide on the traveler car, I'll never reach the 3400lb breaking load of a single strand of SK-90... it'll slip first!

The whip, cross-stitch, and over-whip helped with my sense of denial. :p A clinch knot with multiple wraps would be better for overall line-strength, but in this application that knot takes up a lotta room! Then again, with all my whippery, what I ended up with wasn't small.

The Brion Toss splicing wand looks way more functional than my folded-wire snare/drag.

What I have now tested OK on the water, but just doesn't give me enough of a warm fuzzy feeling to install permanently.

Randii

p.s. Ronstan makes and Oribit with a becket and cam-cleat. Ronstan does it in 55mm and Harken does it in 57mm. Interestingly, one wins in SWL, and the other wins in ultimate breaking load.
https://www.murrays.com/product/21-56130/ and https://www.murrays.com/product/28-2139/

Watch the plastic connector on those blocks. Solid ratchets, but I prefer the swivel version..

The quick links from Ronstan aren't technically spliced correctly, (no way around that), and are lock stitched.

To do something similar at home, well, to do any splicing with 2.5 or 3mm dyneema where you are burying the dynemma into itself I use the D-Splicer kit. An individual D-Splicer F10 needle would work, but currently that isn't available in the U.S.

Martin is dead nuts on when it comes to square knots, avoid at all costs, or if you absolutely have to use them tie stoppers after the square knot and tape the line, but check this regularly as well.

MN3

I like the brion toss tools
if you know how they work you could just use wire

question: how do you use these blocks as a jib block? they dont cleat?

I suspect he meant spinnaker blocks...

Oh, you could tie overhand knots and make a loop that way. Those don't come apart.

FWIW, I have these on my boat for my spin sheets. They work reasonably well, but I've had the ratchet fail on one and the orange plastic ratchet engagement switches seem to be very finicky. Several times I've had the crew go back on the stern only to find the auto-ratchet had disengaged. Does not make for a happy crew in a 20kt breeze.

I'm fairly sure the switches are getting bumped/moved as the crew is moving about the boat during tacks, etc.

Interesting to note you can't get this block attachment design anymore - apparently due to patent issues. They are all swivels now.



Edited by rehmbo on Apr 25, 2018 - 11:51 AM.

--
Jeff R
'88 H18 "Jolly Mon"
'10 C2 USA1193
NE IN / SE MI
cramsailing.com
--

rehmbo

Interesting to note you can't get this block attachment design anymore - apparently due to patent issues. They are all swivels now.

That explains why it is so tough to find them online... other than ebay. I imagine the swivels are more bulletproof, but the soft links lay down nice, and are a bit more agreeable on my crew's backside... and it pays to keep the crew's backside happy, right? :p

Randii

randii

and it pays to keep the crew's backside happy, right? :p
Randii

Put them in a harness . that will save them from being ... violated

Quick update... I wound up buying some extra clips and slings for these to replace my square-knotted loops with whipped/stitched backup. I have thus far been lazy and not changed out my homemade loops, and keeping the replacements in a cat-bag hanging in the ports. So far, so good, but I do intend to change them out next time I'm becalmed or otherwise have boat time to kill.

I did go ahead and order up a proper smaller D-splicer (the medium I had was too large, and the welding wire homemade snare was just too fine), and that's worked well in other splicing (larger loops, spin hoist/douse, etc.). I used the small D-splicer and did up a few small loops using this basis: http://www.animatedknots.com/grogsling/ ... I think these would work in place of the commercial Ronstan links.