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Anchor Swivels - thread drift from another thread


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John B

Posted: Sat Nov 22, 2008 8:02 am

 

Km , since we're on this subject and you've raised that connection ( one that I've had a rant over in the past after I stripped the thread on a chandlers 14 mm bow shackle with a 6 inch crescent) what's your opinion on swivels?

They scare me a bit.. the weakest link and all that, but I like the idea of a cleaner entry/ exit off the fairlead plus of course the swivel action/ chain twist loading and all that.

A few years ago there was a batch failing that one of the chandlers sold , it even made the news.

Are there good brands that don't fail out there ? What do you look for?

 

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wheels

Posted: Sat Nov 22, 2008 9:33 am

 

I am not going to offer advice on swivels as KM is far more experienced than I. But one factor to remember with a swivel is in how your anchor loads on the bow. My anchor is fixed via shackles and the roller is grooved so as the chain always lays one one. This ensures the anchor is always right way up as it loads over the roller and into it's holding area. If the anchor twists around, it will never load correctly and can jam. For some that is not an issue, but for others it is.

I also like to know the anchor is entering the water correctly as I back down. I slowly idle back as I pay the chain out to ensure the anchor is "flying" away from the boat in the correct down attitude and pulling the chain out behind it. I can feel the anchor bite as soon as it touches bottom. Then I let out the depth of chain I want and when I have, I let her set hard.

 

Hey KM, what sort of loads should we expect 8, 10 and 12mm chain to handle before link distortion and complete failure.

 

Oh and while we are on that subject, remember I need a 10mm Tested D shackle with a 25mm throat.

 

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PaulR

Posted: Sat Nov 22, 2008 9:49 am Post subject:

In a twisted nylon rope to chain warp, I think a swivel there certainly helps. Also having a swivel at the bitter end lets all those twists escape.

 

KM: what about the plaited warps

 

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Post below edited to cover swivels

 

 

Knot Me

Posted: Sat Nov 22, 2008 4:18 pm

 

Swivels - Many are dodgy especially the ones that look like 2 shackles bolted back to back. I have yet to see one that can withing 25% of it's stated break load, some have been trashed at less than 35% of stated break load. There are also the eye-eye type that look similar. Again dodgy. I refuse to sell them even to Riviera owners so that's how spooked I am by them.

 

But there are some that are perfectly fine. They are usually the more 'tubular' shaped ones. Kong made in Italy are fine as are the ones by 'Clarke' with the SWL and chain sizes written on them. I know for a fact the smaller Clarke ones for 6-8mm chain have never failed below 4100kg on the test bed. Grade 40 8mm short link (Maggi is the only G40 in NZ and the stuff AC has) has a break of 4000kg so the swivels are no weaker.

 

But there are some that look similar to the Kong and Clarke except a bit flasher that have issues. I think most have a little Dolphin on them, they are branded in a few ways. They don't have a captive center pin which means they can just un-wind and hello, off you go. They also have insufficent side way pull strength so could open the cheeks under load.

 

This is the issue Burnsco had when they thought their local supplier was too expensive and tried to do their own. To Burnscos credit they did go out of their way to get them all back and sort any issues that come from them, big ups for them on that. They don't use them any more and are well over that so no worries on that account.

 

We recommend swivels on any rope to chain rode that use a 3 strand rope. If you have a spinner of an anchor (Deltas, Sarcas, any bent anchor, danforths are common ones. Recently we've had one or 2 say Rocna as well but in all of our testing we haven't seen that) if can twist the chain up quickly on retrieval and once that happens it can carry on and unlay the rope. Rope unlays, splice falls out then the chain and anchor are doing a Titanic.

 

On a 8 braid is not so important as it is a non-rotating rope. That means you can twist it whatever way you like and the lay would open letting the splice fall out.

 

So yes there is a place for swivels even though many (a lot) use them for no apparent reason. Yes there is some perfectly trust able swivels out there. A good swivel is far far stronger than an average commercial shackle.

 

If on all chain or 8 braid we say try your gear and if twisting or spinning is an issue a swivel can be retro fitted in 2 minutes. Save the money for beer.

 

If you need gear like this ask questions and if the answers are vague or just don't sound right be a bit nervous. Ask "what country is it made in?', they should know on mission critical gear.

 

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