Hard v soft eyes?

[neil1967]

I am about to buy a 50m nylon multiplait rope to use primarily as a drogue rope, but also potentially as a tow rope and possibly to extend my anchor rode if absolutely necessary - basically a bit of a multipurpose contingency rope. I have seen that dedicated drogue ropes have hard eyes to allow them to be shackled to the drogue and bridle, but I wonder if soft eyes (possibly in conjunction with soft shackles) would be more flexible to allow for other uses? Would chafe be an issue?

 

[GHA]

There have been examples of damage caused by chafe by the thimbles in hard eyes with jorden series drogues. Maybe cast thimbles would fare better?

 

[AntarcticPilot]

I can't decide! A soft eye means that the rope in the eye is bent more sharply, reducing the strength of the rope and introducing a stress concentration, and of course the rope will chafe at the point of contact. As the pictures above show, a thimble introduces the potential for chafe at the splice. That said, the thimbles shown above look to have deformed under stress; either that ot they're very poorly made, so the suggestion that a different type might be better sounds plausible. I suppose that nylon thimbles wouldn't take the stress.

Looking more closely, is that chafe, or has the splice slipped a bit, allowing the core to escape from the outer?

 

[Yellow Ballad]

I've done exactly the same with 100m of multiplait and went for these https://www.s3i.co.uk/heavy-duty-closed-thimble.php

You do need to get your splice tight and I may even add whipping as well.

 

[Seajet]

For that application I'd go for a hard eye every time, but as above with tight whipping - I use three layers of tight heavy grade whipping in alternating colours for my anchor warp.

 

[GHA]

I can't decide! A soft eye means that the rope in the eye is bent more sharply, reducing the strength of the rope and introducing a stress concentration, and of course the rope will chafe at the point of contact. As the pictures above show, a thimble introduces the potential for chafe at the splice. That said, the thimbles shown above look to have deformed under stress; either that ot they're very poorly made, so the suggestion that a different type might be better sounds plausible. I suppose that nylon thimbles wouldn't take the stress.

Looking more closely, is that chafe, or has the splice slipped a bit, allowing the core to escape from the outer?

Those thimbles were from a jordan series drogue after deployment in a severe survival storm 12m plus seas & winds peaking 80Kts so the loads would have massive.
Behind a paywall unfortunately
https://www.morganscloud.com/2013/06/01/real-world-jordan-series-drogue-deployment/

Bridle had thimbles each end & main line had 1, all damaged. No mention of damage to the soft eyes. Stress concentration not quite so bad on polyester as the little bit of stretch helps spread the load. BIG deal in dyneema, which is why feathering the splice is so important, otherwise the line breaks at the hard end where the splice ends. I've destruction tested dyneema splices before, always goes there without feathering.

Solid quality thimbles would likely have made a world of difference.

 

[thinwater]

I can't decide! A soft eye means that the rope in the eye is bent more sharply, reducing the strength of the rope and introducing a stress concentration, and of course the rope will chafe at the point of contact. As the pictures above show, a thimble introduces the potential for chafe at the splice. That said, the thimbles shown above look to have deformed under stress; either that ot they're very poorly made, so the suggestion that a different type might be better sounds plausible. I suppose that nylon thimbles wouldn't take the stress.

Looking more closely, is that chafe, or has the splice slipped a bit, allowing the core to escape from the outer?

a. If it is luggage tagged around another line, as in a drogue, there is no movement = no chafe. This is well proven on JSDs.

b. Wire rope thimbles (illustrated) always shift when the rope is highly loaded, because the rope stretches. This is extreme with nylon rope. Whipping won't help much with nylon. This is mostly a problem with JSDs, because the load factor is higher than most applications. If you must use a thimble (and there is no reason you must), use either a sailmaker's thimble or a tube thimble. The cheap non-welded thimbles are actually for wire rope, not nylon, but we keep buying them.

c. Weakening. None, because there are 2 legs carrying the load. Not always 50:50 distribution if attached to a hard point, but true when attaching to rope. This is also why a thimble is no needed if the R:r ratio is >=1. This has been tested and is suported by manufacturer data. (around a pulley is a different case)

 

[Daydream believer]

For that application I'd go for a hard eye every time, but as above with tight whipping - I use three layers of tight heavy grade whipping in alternating colours for my anchor warp.

The OP is using multiplait & that does not whip well. Besides one can get a very tight splice to an eye if one knows how. I splice loads of eyes in 25mm multiplait to our moorings in the risers. They take the constant load of the boat . Some have been in the water for 14 years plus.

 

[Roberto]

There have been examples of damage caused by chafe by the thimbles in hard eyes with jorden series drogues. Maybe cast thimbles would fare better?

I have seen the same effect on a heavily stressed anchor cable (or was it a snubber?), anyway the thimble had partially rotated and begun chewing through the rope. Not seen directly but I read a boat was lost in a hurricane as it lost the anchor, they recovered the cable rope and found it split open exactly at the thimble.
Part of the danger comes from the making: they are often used in ropes having elasticity, anchor rope cables, snubbers, etc but the amount of elongation these types of rope have under heavy stress is very difficult if not impossible to duplicate when one makes the splice, so the ring tends to open up.

 

[GHA]

I have seen the same effect on a heavily stressed anchor cable (or was it a snubber?), anyway the thimble had partially rotated and begun chewing through the rope. Not seen directly but I read a boat was lost in a hurricane as it lost the anchor, they recovered the cable rope and found it split open exactly at the thimble.
Part of the danger comes from the making: they are often used in ropes having elasticity, anchor rope cables, snubbers, etc but the amount of elongation these types of rope have under heavy stress is very difficult if not impossible to duplicate when one makes the splice, so the ring tends to open up.

Wonder if that could have been what happened to Susie Goodall when her bridle parted in the golden globe.

Doubt we'll ever know now.

 

[Roberto]

Wonder if that could have been what happened to Susie Goodall when her bridle parted in the golden globe.

Doubt we'll ever know now.

Or maybe to Keith the skipper of one 2017 Ostar boat I met in Horta, he had hurricane force winds, he used the Jordan drogue and said it lasted some time then lost the farther part. All the remaining cones were destroyed.

A bit OT, I think these JSD are a good concept, though often badly built, I have somewhere a photograph of another JSD where rope is intact but all the cones are broken. They are not used often, but the relative number of mechanical failures in the drogue is very high.

Found it, it was in the OCC magazine

 

[GHA]

Or maybe to Keith the skipper of one 2017 Ostar boat I met in Horta, he had hurricane force winds, he used the Jordan drogue and said it lasted some time then lost the farther part. All the remaining cones were destroyed.

A bit OT, I think these JSD are a good concept, though often badly built, I have somewhere a photograph of another JSD where rope is intact but all the cones are broken. They are not used often, but the relative number of mechanical failures in the drogue is very high.

Found it, it was in the OCC magazine
View attachment 75494

Similar happened to Jeanne Socrates with the cones closer to the boat on her last abortive RTW attempt. Part of the problem may be such a small number actually get used in such unimaginable condition for days on end, not many small boats go there. so the severe testing doesn't happen much. All you hear from people that have is praise for the JSD. Seen talk of manufacturers going over to dyneema as shock loading isn't really an issue.

 

[Boo2]

For that application I'd go for a hard eye every time, but as above with tight whipping - I use three layers of tight heavy grade whipping in alternating colours for my anchor warp.

How far up the thimble do you whip, may I ask ?

Boo2

 

[thinwater]

You really need to load up a nylon eye on a test stand to appreciate just how much the eyes stretch and how loose they get.

As far as I am concerned, in a high-load application, any thimble that is not smooth, welded, and preferable captive, is a liability.
http://www.bulldogwinch.com/cartimages/prd_217.jpg?img_id=201810061307520

 

[Boo2]

You really need to load up a nylon eye on a test stand to appreciate just how much the eyes stretch and how loose they get.

As far as I am concerned, in a high-load application, any thimble that is not smooth, welded, and preferable captive, is a liability.
http://www.bulldogwinch.com/cartimages/prd_217.jpg?img_id=201810061307520

Anyone know where you can buy captive thimbles like that in the UK ?

Boo2

 

[thinwater]

^^ DMM makes some nice ones. Also look at arborist sites. They often use them with knotted ropes, where a regular thimble would have no chance of staying in.

Samson makes some pretty bronze thimbles. Overkill for certain, but so pretty.... If I had a wooden classic I would have to use these.
https://www.samsonrope.com/hardware/bronze-thimble/