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Old 19-11-2019, 10:26   #106
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Re: HR shackles can explode

Thereís many ways to splice a loop in Dyneema but this is the strongest and fastest and easiest for the win
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Old 19-11-2019, 10:44   #107
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Re: HR shackles can explode

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Originally Posted by s/v Jedi View Post
There’s many ways to splice a loop in Dyneema but this is the strongest and fastest and easiest for the win
yes, exactly. That's the best practice technique.

I do two very small things differently, but they are just preference and don't make a huge difference to tested strength.
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Old 19-11-2019, 23:45   #108
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Re: HR shackles can explode

Ok, hereís the first test, using the existing 12mm Dyneema core/Polyester cover line with the two Colligo Enhanced Static Lashing Blocks and the 5mm SK78 Dyneema loops double folded into 8 strand baskets.

Click image for larger version

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At the top I used an 8mm Dyneema soft shackle to attach to the running backstay toggle fitting (as this is temporary I didnít want to hassle with putting the basket loop around the pin as Iíll do for the final solution).

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At the bottom I attached the basket loop directly to the 14mm bow shackle thatís in the chainplate. I used an 8mm Dyneema soft shackle to create the becket for the standing part of the purchase line. In the final solution I will eye splice the standing end into the block.

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The line is covered and has a fair bit of friction, so even when I fully tensioned the system the blocks still turned, despite the 4 strands pressing on each side of the rim.

Fully tensioned you can see that the basket loop at the bottom is twisted 90 degrees. Iím not sure if this is an issue. And the pin of the hard shackle is slightly off angle to the chainplate hole; also not sure if thatís a problem or not.

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Overall, seems easy to use the ESLBs as not-static. Maybe no need to strip the cover on the tensioned portion?

To test when static, I lashed the ESLBs in place and tensioned again. Still could apply full tension, but line noisy in the blocks and you can see they wanted to turn. If static, then needs the slipperiness of no cover.

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Thatís the top block. Bottom one was similar.

Hmmm, some good thinking required about static vs dynamic. Iím leaning towards dynamic, acknowledging that it probably means more wear on the basket loops. Still, can cover them in Dyneema to mitigate.
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Old 19-11-2019, 23:47   #109
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Re: HR shackles can explode

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Originally Posted by Breaking Waves View Post
just FYI, just for your interest ....



It would be interesting to break test the full assembly, and see what goes first.. I have tested various size Antal and harken rings with various strops, but not colligoís.


Iím going to break test the basket loops. Iím going to resplice one as a bury loop with lock stitching and leave the other with the Brummell lock. A local rigging shop will do the test.

Which one will go first? At what load? Stay tuned.
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Old 20-11-2019, 07:01   #110
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Re: HR shackles can explode

Quote:
Originally Posted by fxykty View Post
Ok, hereís the first test, using the existing 12mm Dyneema core/Polyester cover line with the two Colligo Enhanced Static Lashing Blocks and the 5mm SK78 Dyneema loops double folded into 8 strand baskets.

Attachment 203451

At the top I used an 8mm Dyneema soft shackle to attach to the running backstay toggle fitting (as this is temporary I didnít want to hassle with putting the basket loop around the pin as Iíll do for the final solution).

Attachment 203452

At the bottom I attached the basket loop directly to the 14mm bow shackle thatís in the chainplate. I used an 8mm Dyneema soft shackle to create the becket for the standing part of the purchase line. In the final solution I will eye splice the standing end into the block.

Attachment 203453

The line is covered and has a fair bit of friction, so even when I fully tensioned the system the blocks still turned, despite the 4 strands pressing on each side of the rim.

Fully tensioned you can see that the basket loop at the bottom is twisted 90 degrees. Iím not sure if this is an issue. And the pin of the hard shackle is slightly off angle to the chainplate hole; also not sure if thatís a problem or not.

Attachment 203454

Overall, seems easy to use the ESLBs as not-static. Maybe no need to strip the cover on the tensioned portion?

To test when static, I lashed the ESLBs in place and tensioned again. Still could apply full tension, but line noisy in the blocks and you can see they wanted to turn. If static, then needs the slipperiness of no cover.

Attachment 203455

Thatís the top block. Bottom one was similar.

Hmmm, some good thinking required about static vs dynamic. Iím leaning towards dynamic, acknowledging that it probably means more wear on the basket loops. Still, can cover them in Dyneema to mitigate.
The twisted loop and shackle: replace both by a single soft shackle. You can sand the metal plate to reduce chafing. I sometimes use a step drill bit to taper the hole, then finish with a Dremel drum sander.

On static vs dynamic: I would remove the cover from the Dyneema. Even if that stops the turning, it still means there is less friction than before. You can then reduce it further with a little block to keep the loop open
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Old 20-11-2019, 07:32   #111
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Re: HR shackles can explode

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Originally Posted by fxykty View Post
I’m going to break test the basket loops.
awesome.

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Originally Posted by s/v Jedi View Post
The twisted loop and shackle: replace both by a single soft shackle. You can sand the metal plate to reduce chafing.

I am guessing/hoping there is a stainless bushing in that toerail hole where the bow shackle goes? You would need to knock the bushing out to follow Jedi's suggestion - not hard to do, and his suggestion is a good one but it may involve more 'boat modification' than you want to do. If so, there is a pretty easy way to configure a lashing there to remove the twist.

Since it has not broken or deformed yet, it is probably not a huge issue.... but that shackle to toerail attachment is not totally 'proper' as is - I guess the hole is too big for the pin and it is point loading. If you leave the shackle it would be proper to bush down the hole (or upsize the shackle pin) so that it is a close fit thru the hole and thus not point loading.




On static vs dynamic: I would remove the cover from the Dyneema. Even if that stops the turning, it still means there is less friction than before.

yea, I would strip the cover also - less friction, lighter, less aero drag what's not to like. A very little less UV but not a huge amount less and if you coated the stripped portion with something like maxi-jacket it would be as good as the cover.
Nice job working thru this so far. I personally think I would have just gone for a Karver block but that would have been the easy/expensive solution (and you would still have had the toerail/shackle pin issue)
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Old 01-12-2019, 00:53   #112
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Re: HR shackles can explode

Almost done, still waiting for bushings to be fabricated that will fit over the shackle pin to fill the current chainplate hole. Also, once we re-rig and change the SS wire running backstays with Dyneema, the running backstay will be spliced directly through the upper Colligo blocks in the same way as the standing part of the purchase is spliced to the lower block.

Click image for larger version

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Upper block is attached to the bottom of the running backstay, to a toggle fitting. The block needs a shackle as the space in the toggle pin was not enough for the ends of the basket loop. 10mm HR is good enough for now (no open ocean passages before the re-rig).

Lower block is attached to the 14mm 316 SS bow shackle fitted through the chainplate hole.

Iíve covered each of the the basket loops and the eye splices with Dyneema cover, all four strands together and sewn whippings holding the ends of the cover. I havenít installed spacers like the Ropeye or Ino-Rope blocks have got as I want to see how it works without first. No need to complicate if not necessary.

Click image for larger version

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ID:	204132

I stripped the cover from the purchase line just for the section under load in the purchase. The
Dyneema core slips easily on the large diameter Colligo blocks - even under full load there is no sound from the system and no apparent extra friction relative to the Harken Air Blocks with roller bearings that were there before.

First test was today, sailing to windward in 25 knots and a 2m wind chop. We were double reefed main and full jib and ran full tension on the running backstays. Given the failures of the previous gear we put about 1500kg of winch tension through the 2:1 purchase - thatís pretty much full strength on a 10Ē handle on a 53 ratio winch. Winding in the running backstays was completely smooth. The Dyneema core slid on the blocks, which were held tight by the basket loops and spliced eye. Thereís only about 20cm of line movement out of the bottom block from the time tension starts through to not being able to wind more on.

So far, so good.

Simple and reliable system with easily inspected parts, and costing about 20% of the equivalent roller bearing blocks.

Still waiting for the break test - hopefully this coming week it will be done. Meanwhile, all my basket loops started with a Brummel locked loop and 60x bury.
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Old 01-12-2019, 02:29   #113
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Re: HR shackles can explode

That just looks sexy! Good job


Matt
Quote:
Originally Posted by fxykty View Post
Almost done, still waiting for bushings to be fabricated that will fit over the shackle pin to fill the current chainplate hole. Also, once we re-rig and change the SS wire running backstays with Dyneema, the running backstay will be spliced directly through the upper Colligo blocks in the same way as the standing part of the purchase is spliced to the lower block.

Attachment 204131

Upper block is attached to the bottom of the running backstay, to a toggle fitting. The block needs a shackle as the space in the toggle pin was not enough for the ends of the basket loop. 10mm HR is good enough for now (no open ocean passages before the re-rig).

Lower block is attached to the 14mm 316 SS bow shackle fitted through the chainplate hole.

Iíve covered each of the the basket loops and the eye splices with Dyneema cover, all four strands together and sewn whippings holding the ends of the cover. I havenít installed spacers like the Ropeye or Ino-Rope blocks have got as I want to see how it works without first. No need to complicate if not necessary.

Attachment 204132

I stripped the cover from the purchase line just for the section under load in the purchase. The
Dyneema core slips easily on the large diameter Colligo blocks - even under full load there is no sound from the system and no apparent extra friction relative to the Harken Air Blocks with roller bearings that were there before.

First test was today, sailing to windward in 25 knots and a 2m wind chop. We were double reefed main and full jib and ran full tension on the running backstays. Given the failures of the previous gear we put about 1500kg of winch tension through the 2:1 purchase - thatís pretty much full strength on a 10Ē handle on a 53 ratio winch. Winding in the running backstays was completely smooth. The Dyneema core slid on the blocks, which were held tight by the basket loops and spliced eye. Thereís only about 20cm of line movement out of the bottom block from the time tension starts through to not being able to wind more on.

So far, so good.

Simple and reliable system with easily inspected parts, and costing about 20% of the equivalent roller bearing blocks.

Still waiting for the break test - hopefully this coming week it will be done. Meanwhile, all my basket loops started with a Brummel locked loop and 60x bury.
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Old 01-12-2019, 02:40   #114
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Re: HR shackles can explode

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That just looks sexy! Good job


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Yes, nice to see these developments on CruisersForum
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