FF
Guru
- Joined
- Oct 12, 2007
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"imagine many subjects that will spur more heated debate than anchoring or anchoring systems. "
Single Vs Twin?
Gas Vs Diesel?
Single Vs Twin?
Gas Vs Diesel?
FWIW this is a KONG swivel, manufactured in Italy. Just found this out in the process of looking up something else.Larry M wrote:
*
Here's the picture of the swivel failure.
hollywood8118 wrote:
they have by far the coolest.. massive Stainless steel swivel I have ever seen.
Install it incorrectly, however, in such a way that it cannot pivot to line up with the rode no matter which way the rode is angling in to the anchor and I'll guarantee you that the sideload shear strength of the swivel pin is a lot less than 25,000 pounds.* By which I mean the pin or stud that the two halves rotate around, not the horizontal pins at each end that fasten to the anchor and rode.* That center swivel pin is the weak component in every swivel if it's subjected to side loads except the WASI Powerball, which doesn't have a swivel pin.Delfin wrote:
I use 1/2" G4 chain and a SunCor swivel with 3/4" pins and a 25,000 pound breaking point.
The design of this swivel has the built-in flaw that Earl Hinz talks about in his book.* The top half swivels against the bottom half using a stud or a pin as the "axle."* But no matter which end you attach to the anchor the swivel will only be able to rotate back and forth in line with the anchor shank.* Unless you attach it correctly with a shackle which will then allow the swivel to "aim" in any direction* relative to the anchor shank.*Delfin wrote:
Marin, if you look at the design in the link you'll see there is no side swivel, so your point is incorrect.* The only loads possible are parallel to the line of the rode, which is why this is the design I chose to solve the problem the original poster described.
If chain "twisting" causes a swivel to break then what is the purpose of a swivel in the first place?* If this is true you make an even better case for not having a swivel than anyone else in this discussion has so far.* A swivel's whole purpose and*design*is to allow the top half of the swivel to swivel relative to the bottom half--- hence the clever name--- when the chain starts to twist.Delfin wrote:
FF, if you look at the picture sent with the inital post, you can see that the twisting has created sideloading on the shackle so that the strength is likely reduced, perhaps by a great deal.
Since every boater I know personally who anchors a lot has no use for a swivel in their rode, and we don't use a swivel, and given that the waters we anchor in are constantly moving our boats around our anchors, and I've not heard anyone I know who uses an all-chain rode ever say they've had a problem with an anchor rode twisting or kinking when they retrieved the anchor, I would say that what you wrote makes all sorts of sense.Larry M wrote:
So that says the boat could rotate/twist 60 times without the*chain kinking?* Does this make any sense?
I dislike it when an anchor makes an unanticipated motion that can damage*the boat or me.* That's why I don't like anchors with moving parts.* (Being pinched twice*by a Danforth was too much.)Marin wrote:
...* --- the anchor still came up any way it wanted to. In fact the swivel seemed to make it easier for the anchor to rotate around and whack the bow.* We eliminated the swivel for the reasons I've outlined earlier, but I've also noticed that without it the anchor is far less likely to rotate around as it comes up.* It may not be oriented correctly, but it doesn't swivel around as much when it's in the air.* This was true with the Bruce as well as with our current Rocna.
-- Edited by Marin on Tuesday 12th of October 2010 12:40:19 PM
The concern is that as the boat "circles" the anchor--- which it can and does up here but perhaps not in other waters with a lower or no tide range and minimal to no current changes--- the chain can be dragged around in one or more circles which can roll it over multiple times as this happens.* Even if there is little or no load on the anchor, the boats up here still move around a lot and drag their chains around on the bottom after them.*Giggitoni wrote:
I've watched these threads through the years regarding swivels.* This is the way I look at it...* If the anchor is set in the substrate and the other end of the chain is set across the rollers and onto the windlass, how can it twist at all?
Plus anything hanging from a crane or suspended vertically like this is going to have the load on the swivel going straight through it, which is when a swivel is at its strongest.nomadwilly wrote:
They showed the thing they're going to bring the Chilean miners up in and it clearly had a swivel attached. It was one of those barrel like swivels. I can see the possible need for it there.....