Nylon vs Stainless Thimbles
 

I am about to splice an eye in both ends of a 1/2 inch 3 strand nylon anchor rode. While I have two nylon thimbles for the eyes, should I use stainless thimbles in the eyes? The eye will hold a shackle attaching the nylon rode to 5/16 chain, and I want to be able to end for end the line sometime down the rode. (Sorry!) I'd appreciate any thoughts on the matter.

Thanks,

Stephen Hill
Crown 34,
Victoria, BC

Ian McColgin
 

Absolutely on an anchor rode use the SS eyes.

Open nylon eyes have only the most limited utility as there are few instances where such light use as suits them will result in any meaningful chafe.

Closed nylon eyes are stronger but still, why have something weaker than the line your using?

I use closed nylon eyes in the lazy lifts (called around here Lazy Ians) that are a big improvement over the sort of desperatly over-engineered lazy jack systems complete with bullet blocks that are sold in catalogues. Other than that, SS it is.

G'luck

Ian

Or...
 

Hello,
As Ian notes, nylon is not the best material; the only boats that I've seen happy with nylon anchor thimbles are boats that don't anchor much, and/or under much load. But even stainless thimbles can be a problem, as they can get sideways in the eye (nylon rodes stretch, right?), and eat their way through the line that they were meant to preserve. Therefore, since you're not going to do a rope/chain splice, consider either a bronze ''keeper" thimble, with built-in straps to keep the thimble from rotating, or splicing directly to a shackle with a Crown Splice. I'd prefer the latter in most instances.
Fair leads,
Brion Toss

Ian McColgin
 

I quite agree with Brion that the crown splice is best if one does not plan do do other things with the rode, like bend it to another rode or use as a tow line or whatever, and especially if youv'e a rope-chain gypsey or smallish hawspipe.

The bronze keeper thimbles are absoluetly best. I've also used steel versions aboard a tugboat where the strains are truely huge and a quickly made up eye was not very snug anyway.

Bur for yacht sized mooring pendants and anchor rodes,. the normal open thimble, even if spotwelded for strength at the neck, still has so much flange that I've not observied any twisting out or causing chafe.

Take a normally shaped thimble for 1/2" line. In destructive tests I did about 25 years ago, the line would fail at about 30% stretch. I understand this is normal. This leaves 15% stretch around the thimble as the load is shared. I think that the splice's bulk actually keeps the line in the eye from stretching even that much.

I use the "prosplice" which gets the throat in more tightly than the "Boy Scout" approach to starting the eye. I can certainly see how a clunkly and loose throat could lead to trouble.

I never observed the throat of the eye emerging from the flanges of the thimble though I believe just prior to rope failure the inner part of the rode might have gotten as much as 1/2" away from the inside throat metal of the thimble. Hard to tell guessing from the visible strands and I did not want to get anywhere too close.

The rode nestles into the flange tightly long past the side tangents normal to the apex tangent because even stretched they legs of the eye are converging. I think that it really can't twist out unless one does an incredibly sloppy and loose splice.

So, in years of splicing up some hundreds of mooring pendants, I've not had a failure induced by the thimble slipping or by chafe at the throat. Those that fail mostly chafe through due to poor bow chocks or refusal to maintain decent chafe gear up above. Moorings very seldom fail due to pure pendant at breaking strain or lower eye failure.

On anchor rodes that are used hard and are eye spliced to the chain, I worm and parcell the eye before splicing. I also carry chafe gear down the splice and out each side of the eye a little, somewhat capturing the shackle into a narrower range of movement, and giving the sides of the eye a bit of protection against chafe along the bottom. Perhaps all that "braces and belts" reduncancy is why I've not worried about thimbles hopping out.

That's my anecdotal experience but it may not be generalizable. My question for Brion is, have you observed enough throat chafe or thimble slither that this is really worth worrying about? Have I been living in a fool's paradise?

One further question: Are you now advocating dacron rather than nylon as dacron's superior abrasion resistance outweighs any advantages from nylon's stretch? Or did I just imagine that?

Thank you & G'luck

Ian

Wow
 

Hi Ian,
I watched one boat go ashore because of thimble chafe, and some years later helped arrest the progress of a second (think two guys in an old Peapod, 40 knots, square waves, oncoming lightning), so I know it's possible for the thimble to kill the rope. But I'm sure that neither eye was spliced with the care and skill that you describe for your rodes. Perhaps I should amend my story to say that non-keeper thimbles (heavy-duty preferred) are only for consummate professionals.
Fair leads,
Brion Toss

What is the "prosplice" method?

Ian McColgin
 

I think it's in Brion's book.

Two different ways:

Make one tuck, an over and a second tuck with the first strand, then start the other strands even with the emergence of the first, or

Tuck the first strand under two strands and then on to second and so forth.

Either way makes for a nice clean start. I never figured out why the BoyScout method is even illustrated.

G'luck

Ian

Thanks Ian
 

I've been following "the book" in doing just that....didn't know or remember that it was called "prosplice" versus the "agricultural method".

Additional question: What does one "do" with double braid nylon which should have the old rusty thimble replaced? I can't imagine putting in another eye splice for a thimble in USED nylon...it is nasty enough in new line yet I don't want to throw away perfectly good line....what to do?

Thanks,
Rick

Ian McColgin
 

I just rethimbled a double braid rode for some friends. Thought I had the macho to eye splice it and thus wated a few hours and almost eight feet of line.

I did a siezing almost 6" long as follows.

1. Siezed the bitter end to the standing part allowing about 6" before it even got to the throat of the eye. This siezing was waht I call "racked" and I don't recall the correct term. My copies of all my rope books now sleep with the fishes after Granuaile's pre-Memorial Day sinking and destruction so I can't look it up but someone will remind me. Anyway, by racking I mean the passing the line normal to the windings and between the two parts of the eye. I made this siezing about 1" long.

2. I tied the rode to a tree maybe 20" down from the new eye. I set up a tackle around the eye and to another tree, put the thimble loosly in the eye, secured that to the end of the tackle and hauled as hard as I could. Given it's a 5: tackle and given my general heft, I had just shy of 1,000# stree there. This ensured that both halves of the eye were nicely stressed.

3. I made two more 1" racked siezings working from the first siezing down towards the eye and leaving 1" between each.

4. I then filled in the two gaps between siezings and lastly the gap from the last racked siezing to the thimble with plain siezings.

5. I put that rubbery rigging tape (siezed at the end to absolutely prevent unraveling) over the whole except the last windes of the bitter end siezing mainly to keep mud granuals from getting in between the siezings and the rode parts and causing a kind of internal chafe. I left enough of that end siezing out that should there be a start at failure, it could be visible.

I think it important to put some strain on the eye before completing the siezing and to work from the bitter end towards the throat of the eye and a siezed eye depends very much on a nice even sharing of the load.

G'luck.

Ian