Two Anchor Swivels

[sailingharry]

Originally Posted by flightlead404

I’m no expert but have anchored an couple hundred nights over the 2 years and have seen no need for a swivel. My rocna does occasionally try to stow inverted when it has a heavy load of mud on it, but a quick lower and raise will cure that

A trick that works for us when the admiral can't get the Rocna to face the right way. She asks me to back down. A knot in reverse for a boat length will usually do it. Seems the anchor wants to lead with the point, so backing down turns it point back.

[Dockhead]

Originally Posted by flightlead404

. . . We had no issues but one of the standard half derelict semi-live aboards here broke loose because the swivel failed

Not scientific, but my impression is that the great majority of ground tackle failures are failed swivels.

[NSboatman]

Originally Posted by Charlie

Hi All:



Just bought a new boat in Ireland. A ten hour flight away. The previous owner had the boat for 10 + years and never anchored. Good thing as well since his anchor gear consisted of : 1) SS Bruce Anchor, 2) SS swivel, 3) About a meter of SS 3/8 chain, 4) a very cheap, non welded, and rusted chain link, and Finally 4) 30 meters of galvanized 3/8" chain. The 30 meters of chain is in good nick. I am thinking of putting another SS swivel to connect the SS to the Galvanized. The layout of the tackle is such that the second swivel will never touch the windlass. Two problems that I see are 1) It does fail the KISS principle and 2)It adds a second failure point. I am okay with these as the SS does look better going into the anchor locker.



Are there any other problems that anyone can see with the setup that I am envisioning?



My second option would be to remove the SS chain and go directly to the galvanized.

This.

[NSboatman]

Originally Posted by Dockhead

Not scientific, but my impression is that the great majority of ground tackle failures are failed swivels.

And this. I know if 3 boats now that were lost due to swivel failures.

It is a rare situation that requires a swivel. No swivel = one less failure point. And it’s a big one.

None of my moorings or anchors have swivels, and they never will. There is no need where I anchor or moor.

If the tidal streams or current requires the use of a swivel, then I’d spend as little time possible in that location - and deal with the twisting and snarling that occurred from having no swivel, rather than introduce these vile beasts into my lifeline.

[flightlead404]

Originally Posted by MicHughV

This will require another shackle, unless you want to splice the nylon to the chain. I find it simpler to use another shackle.

The. Ice thing about backsplicing line into chain is that it will go through the windlass whereas a shackles won’t. I’m really glad I did on my primary ride and thinking about removing the thimble and shackle on my secondary for that reason

[MicHughV]

I'm fairly adroit when it comes to splicing line, but my efforts at splicing a line to a chain has, to date, been a cluster.....I seem to develop 10 thumbs...so have to resort to the shackle and live with the end result...

[NSboatman]

Originally Posted by NSboatman

And this. I know if 3 boats now that were lost due to swivel failures.

It is a rare situation that requires a swivel. No swivel = one less failure point. And it’s a big one.

None of my moorings or anchors have swivels, and they never will. There is no need where I anchor or moor.

If the tidal streams or current requires the use of a swivel, then I’d spend as little time possible in that location - and deal with the twisting and snarling that occurred from having no swivel, rather than introduce these vile beasts into my lifeline.

Perhaps another point to make here is that there is nothing fundamentally wrong with a swivel in concept- it serves a good purpose to avoid hockling and twisting of lines in situations where there is a regular flow reversal.

They are used frequently in offshore structures and semi-permanent moorings; and indeed are present on some large nav aid moorings- and don’t typically fail.

The real issue for cruisers is that the quality and reliability of the swivels that we can easily access and afford is variable at best.

If you use a properly rated (DNV/Lloyd’s/BV/ABS/RINA/etc) and tested swivel; it’s unlikely to be the weak link in your (otherwise consumer grade- which is to say no-grade) system.

Trouble is- these swivels are huge, and bloody expensive- like more than your entire chain/anchor+windlass assembly!

[noelex 77]

If you are going to use a swivel, make sure it is a good quality model.


[/QUOTE]

[noelex 77]

Originally Posted by Anders

The purpose is to avoid sideload on the swivel incase the anchor ger stuck on something.

Spot on .

This is what you are trying to prevent:

[/QUOTE]

[NewMoon]

Originally Posted by noelex 77

If you are going to use a swivel, make sure it is a good quality model.

Like this one from Mantus - vastly superior to the design shown above:

[MicHughV]

Marine Manufacturer " Hey Bob, business is slow, we need to come up with a new gadget to foist off onto sailor's, how about another anchor design ?
Bob " Nah, we've done too many of those, I've got an idea, why not an expensive replacement for a shackle"
MM " Bob. brilliant thinking....how much is a regular shackle.... ??"
Bob " About two bucks"
MM " how much can we get for your new idea ?"
Bob " we'll make it from stainless steel, so that it's nice and shiny, new boat owners love that shiny stuff, and we could probably get $50-100 apiece for it"
MM " excellent idea, will it work ? "
Bob" not as good as two shackles, but who cares, we'll be making money !"
MM " excellent, we'll call it an anchor swivel, make 'em in different sizes, so we can sell the idea to small and big boat owners..."

and the beat goes on.....

[Anders]

Originally Posted by NewMoon

Like this one from Mantus - vastly superior to the design shown above:

Or a Kong. Mine is stronger than the chain. It will never break.

[Fuss]

Originally Posted by noelex 77

Spot on .



This is what you are trying to prevent:

[/QUOTE]



That swivel is not suitable for marine use. If it was, the shank would have bent.

[noelex 77]

Originally Posted by Anders

Or a Kong. Mine is stronger than the chain. It will never break.

Kong make good quality swivels. In a direct straight line pull if you choose the recommended model may be stronger or weaker depending on the chosen chain.

For example, the Kong 8-12mm model has a break load of 5000 Kgf and a SWL of 2000 Kgf

8mm G30 chain has break load of around 3100 Kgf and a SWL of 770 Kgf

12mm G40 chain has break load of around 9200 Kgf and a SWL of 2300 Kgf


However, problems occur with side loading. At 45° the break load of the Kong swivel drops to 2000 Kgf (no SWL listed). This is well below the strength of chain.

Kong provide a warning:
“When using a one-piece solid anchor, the risk of lateral (not straight in-line)
stress highly increases. Using an appropriate shackle between
the anchor shank and swivel may be advisable
to reduce lateral load risk.”

Very few people heed this recommendation. Rather than using the extra shackle, a short link of chain (3 or 5 links) is better even though the risk of this jamming and binding is higher.

These extra links of chain are not required on some swivel designs such as the Mantus, Ultra and Wasi, as these models can pivot to reduce the side loading, but on the Kong style fork swivels protection from lateral loads is important.

[NewMoon]

Agreed. We had a Kong, attached directly to the anchor. It bent from side loading, much like the picture above, and would easily have broken if we had not noticed the bend. My boating buddy's Kong did the same.

We switched to the Mantus. In 8-9 years and close to 1000 anchorings on the Inside Passage it shows no sign of wear and tear. We do re-wire every other year or so, and inspect the wire regularly.