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Old 11-01-2019, 21:42   #16
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Re: Racing sailor killed due to splice failure

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Originally Posted by funjohnson View Post
I see a tapper on both of the brummel splices with the rings on each end. Plus, there is stitching back-up too...

It looks to me like the line failed mid way nowhere near the splices. The article says that instead of using two individual strops, the rigger used one longer length of line with rings on each end. That would make the splices on the end and not in the middle.... or was it spliced in the middle to connect the two strops? If he did splice the two together with just a brummel, then that is ridiculous stupid.

Maybe it was around fitting with too tight of a bend radius?

Attachment 183677

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Look at figure 13 page 29 in the MAIB report.
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Old 11-01-2019, 22:13   #17
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Re: Racing sailor killed due to splice failure

In terms of strength, what is the advantage of the splice over a normal halyard hitch ?



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Old 11-01-2019, 22:21   #18
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Re: Racing sailor killed due to splice failure

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Originally Posted by Topspin View Post
In terms of strength, what is the advantage of the splice over a normal halyard hitch ?



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Dyneema looses a lot of strength when tied. A preventer is a very high load application.
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Old 12-01-2019, 05:35   #19
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Re: Racing sailor killed due to splice failure

Quote:
Originally Posted by funjohnson View Post
I see a tapper on both of the brummel splices with the rings on each end. Plus, there is stitching back-up too...

It looks to me like the line failed mid way nowhere near the splices. The article says that instead of using two individual strops, the rigger used one longer length of line with rings on each end. That would make the splices on the end and not in the middle.... or was it spliced in the middle to connect the two strops? If he did splice the two together with just a brummel, then that is ridiculous stupid.

Maybe it was around fitting with too tight of a bend radius?


Matt
This is the first time I saw this photo. I agree it is hard to call it a splice failure.

Look carefully at the top 1/2 it looks like someone ironed it flat. Then look at the bottom 1/2. Carefully count the loose ends. I am counted 8, or the number of “big” threads in a single braid line. If this count is correct, then there was no splice in the failure area. This reinforces the assumption that it was not a splice failure.

IMHO it appears to be a rigging failure, likely as the result of chafe. It would be useful to know how long this line was in service and how long was it used on this trip? Also when was the last time the skipper or crew inspected the line?

I think the take away from this is reinforcement of the knowledge that dyneema does not tolerate chaffing. Adding an outer sleeve, and monitoring it for where may have avoided the failure.
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Old 12-01-2019, 05:49   #20
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Re: Racing sailor killed due to splice failure

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Originally Posted by thinwater View Post
The actual error was in believing that the brummel lock could hold the load without the long tail bury. It is the long bury with taper that provides the strength, and the brummel is just one way to keep the splice from working loose when not loaded.


This was on one of the Clipper Round the World Race boats. A full report is on line by the MAIB.

Yes.


The strop was not spliced at all:


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https://www.sailingscuttlebutt.com/2...nked-fatality/


There was just a Brummel lock with no splice. A very stupid way to rig that preventer.


Some people in this thread seem to be confused about the purpose of stitching a Dyneema splice. Stitching has nothing to do with holding under load. Stitching is just one way to prevent a long bury splice from working loose when there is no load -- that's all it does.


A Brummel does the same thing and does it perfectly well, probably better than stitching.


There's no substitute for a long enough bury. Splices in Dyneema single braid work according to the Chinese finger trap principle, and the material is slippery, so the length is critical. Note that Brian Toss and other gurus have increased the recommended length of the bury not long ago -- word to the wise.
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Old 12-01-2019, 07:16   #21
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Re: Racing sailor killed due to splice failure

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Originally Posted by Dockhead View Post
...The strop was not spliced at all:


Attachment 183688


https://www.sailingscuttlebutt.com/2...nked-fatality/


There was just a Brummel lock with no splice. A very stupid way to rig that preventer....

^^ This. Whether you call it a splice or not is semantics. The rigger use a brummel lock in place of a proper splice, weaking the construction by about 50%. That was dumb to the point of unconscionable. I think folks may be struggling to get their arms around what he actually did.



Why the MAIB suggested Marlow and other rope makers do more to caution people about bad splice practices is beyond me. No ONE suggested using a brummel alone. He was off the reservation with that, and every good rigger knows that. Basically he tied a bad knot. How can they caution about every misuse of their product? It's enough that they show how to splice correctly.


The other odd thing is that they had spares spliced up on board. They had broken this before. Did they accept that it was a fuse? In that case maybe the brummel was not a mistake... others can judge whether that makes sense.
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Old 12-01-2019, 09:48   #22
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Re: Racing sailor killed due to splice failure

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What is the $ to death ratio so far Sir Robin?
Sir Robin? As in Robin Knox-Johnston? Sir Robin had nothing to do with this tragedy, unless perhaps he was the captain of the vessel. Which he was not. It wasn't Knox-Johnston's race, and even if it were the ultimate responsibility rests with the skipper. Ocean sailing is dangerous, ocean racing ridiculously so. Sir Robin is a legend, as he should be. No one had ever done what he did - which MANY people felt was impossible - and no one else ever will. Leave him alone.
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Old 12-01-2019, 10:10   #23
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Re: Racing sailor killed due to splice failure

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Sir Robin? As in Robin Knox-Johnston? Sir Robin had nothing to do with this tragedy, unless perhaps he was the captain of the vessel. Which he was not. It wasn't Knox-Johnston's race, and even if it were the ultimate responsibility rests with the skipper. Ocean sailing is dangerous, ocean racing ridiculously so. Sir Robin is a legend, as he should be. No one had ever done what he did - which MANY people felt was impossible - and no one else ever will. Leave him alone.

I think the question is whether the passengers fully understand the risks and whether they are truly prepared. They are not prepared at the same level as pro crews or even truly advanced amateurs. The same subject comes up with guided mountian climbing; the guide can make it safer, but he can't make it safe, and not all of the customers are truly prepared. Guided climbers are generally not as well prepared as skilled amateurs that would take on the same climb without a guide. Much depends on the willingness of the guide to say "no, you are not ready for this."



Yes, some related to gear failures that should not have happened. On the other hand, in each case there was also a human factor (two sailors were clipped improperly and the other loitered over the traveller track).



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Old 12-01-2019, 10:43   #24
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Re: Racing sailor killed due to splice failure

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...i think there is information in this article for all of us to ponder...and absorb
Shows our need for redundant and oversized systems.
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Old 12-01-2019, 10:44   #25
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Re: Racing sailor killed due to splice failure

From Dockhead: A Brummel does the same thing and does it perfectly well, probably better than stitching.

This is incorrect in most situations and is easy enough to prove. It the line is under constant tension, even a little bit, a brummel has a good chance of preventing the loosening of the burried tail. However, take an unstitched brummel, with an appropriately burried tail, and put line in compression and tension repeatedly, change the duration, let the line just go slack a bit then back to tension, it is not long before you can see the tail start to creep out of the bury. One it starts, things can go downhill quickly. In an application like a preventer, where a line is loosely loaded and unloaded continually, it is easy to see a bury coming loose. Try it with a 3mm dyneema line, it comes undone very quickly.

Always stitch brummel or straight bury splices. If you don’t, you have not completed the splice.
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Old 12-01-2019, 15:11   #26
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Re: Racing sailor killed due to splice failure

So how would you do a long bury on on the lefthand loop on this strop? This is a picture of the strop setup that was in use.
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Old 12-01-2019, 15:26   #27
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Re: Racing sailor killed due to splice failure

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So how would you do a long bury on on the lefthand loop on this strop? This is a picture of the strop setup that was in use.

You don't. You make two independent loops or dogbones, as many people have suggested. Easy to buy, easy to splice, predictable strength. What was done was an unfortunate shortcut.

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Old 12-01-2019, 15:50   #28
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Re: Racing sailor killed due to splice failure

My preventer is made of thinnish three strand nylon, it is designed as a fuse to break before the boom breaks if it and the main are immersed.

Don’t get this concept of a preventer that can’t break.

What is the current recommendation for length of bury for a Brummell in dyneema?
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Old 12-01-2019, 15:57   #29
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Re: Racing sailor killed due to splice failure

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Originally Posted by thinwater View Post
You don't. You make two independent loops or dogbones, as many people have suggested. Easy to buy, easy to splice, predictable strength. What was done was an unfortunate shortcut.

I don't really see the advantage of the 'short cut'. Two seperate ones make it straight forward, I was just wondering if there was a method to splice the dual strop that allowed you to bury the inner loop. I couldn't see a way.
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Old 12-01-2019, 15:59   #30
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Re: Racing sailor killed due to splice failure

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Originally Posted by olaf hart View Post
My preventer is made of thinnish three strand nylon, it is designed as a fuse to break before the boom breaks if it and the main are immersed.

Don’t get this concept of a preventer that can’t break.

What is the current recommendation for length of bury for a Brummell in dyneema?
The preventer needs to be way strong, but if somethings needs to break, then better the preventer than tbe boom or gooseneck.

The tapered bury is generally 72x the diameter, with or without the brummel. The brummel does not add any strength, it actually reduces strength in some tests.
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