Lost Our Boat Due To A Bad Mooring Swivel...

[sparrowhawk1]

Originally Posted by Shaneesprit

Really never seen one with a swivel ?
I have never seen one without a swivel,
Without a swivel the boat could twist the chain 360’ twice a day, the chain would tighten and the mooring block would almost certainly lift.
If there were no swivel I wouldn’t leave my boat on a mooring for very long.
In this case a cause of failure, in most cases it prevents failure.

So strange to me that people even sailors with experience don't understand the necessity of a swivel. Fact :boat rotate. And yes I left out the S on purpose.

[NSboatman]

For those who are interested in the full story of the loss of Nahanni V, beautifully written with wonderful vignettes of humanity and care; John and Kathryn have posted the details on their blog.



It must have taken a long time to write, and been very painful to do.



The result is a touching and inspired piece. It shows the care, love and incredible leadership and parenting they both have managed to show through the whole event.


Definitely worth sitting down, with a drink in a comfortable chair, and reading over some time. My heart still goes out to them!


To add even more to my respect for them - I believe they're headed out on another sailing adventure this autumn! Getting right back on that horse...


here's their blog:Nahanni V at Sea


bg

[chris95040]

Originally Posted by Jim Cate

Some friends of ours have their mobile phone number displayed at each of the boarding gates in the lifelines... just where a good Samaritan is likely to see it when coming to board to accomplish their good deed.

Seems a good idea with no down side.

Jim

Well, everything's got a down side, at least an imaginary one.

What I've heard folks say about the 'phone number on the boat' is some jerk could get an idea for how far away you are by calling you with a fake issue, and then leisurely robbing you blind knowing you won't be there "for another hour or so".

I still leave my number on deck when I'm leaving the boat at anchor, though.

[Jim Cate]

Originally Posted by chris95040

Well, everything's got a down side, at least an imaginary one.

What I've heard folks say about the 'phone number on the boat' is some jerk could get an idea for how far away you are by calling you with a fake issue, and then leisurely robbing you blind knowing you won't be there "for another hour or so".

I still leave my number on deck when I'm leaving the boat at anchor, though.

I've got better things to worry about! The postulated scenario reeks of paranoia.

Jim

[tjandoverguy]

would u diagram the extra line u attatch

[ebsail]

so sorry for your loss. Here at the Nyack Boat Club on the Hudson River in NY our entire fleet of almost 100 boats is exposed to any wind from North, East or South. We no longer allow any chain, shackles or fittings and even pendants that are not made in the US, or in some cases, the Netherlands. Each and every component should be rated at the entire weight of the vessel. Losses have gone from as high as 6% during superstorm Sandy, to currently about 2%. And even that low number is generally due to pendant chafe, or a member not examining their gear for years.

[Wind River]

So sorry for the loss of your boat. I could have ended up with the same fate but I was simply lucky.

I had the same failure on the same type of swivel on my mooring in San Diego Bay. I was lucky that mine failed during daylight hours and I was in a very popular area off Shelter Island right next to a large fishing pier. Someone actually saw my boat start to drift and called it in to the Harbor Patrol. I was hours away from the boat at the time and got a call from the mooring company telling me of the situation.

The fishing pier was only about 100 yards away and my masts were out of my boat at the time for repair. It likely would have gone under the pier destroying my boat and the pier. As luck would have it, the outgoing tide sent it out in the bay towards the Navy docks so there was no way the Harbor Patrol or Navy was going to let it get too close. Harbor Patrol held on to my boat while they waited for Boat US to come take it off their hands. Boat US put it on the public dock and by the time I got there it was tied up and they were gone.

My swivel was a 3/4" swivel and was nine months old, purchased at the local Marine Chandlery. I have been changing my mooring lines and swivel about every 6 months as I am in and relatively rough area of the bay and my boat is very heavy (52,000 lbs). I had put on new mooring lines onto this swivel a couple weeks before but didn't change it as they were out of stock when I went to get a new one. The swivel still looked good enough to wait another week or two until I could replace it.

The swivel broke the same as yours did. The weld broke and the nut unscrewed. My theory is that there is enough play in these large threads that the only thing really holding this swivel together is the weld, as the nut is not tightened against anything to load the threads and keep them them tight together. This weld take the constant hammering of the motion and eventually fractures allowing the nut to unscrew.

Since my boat swings on its mooring, I found a swivel was necessary otherwise my mooring lines get severely twisted and wrapped around the chain below the ball. It is also complicated by the fact I use two mooring lines. One is about a foot longer than the other so it is always in good shape with no chafe as it is never loaded. It's only there as a back up, but it has to be connected to the same swivel so everything is hanging the integrity of that swivel. I just don't know of any other options other than a swivel to mitigate the twisting and knotting up of the lines.

[Group9]

Originally Posted by NahanniV

One of my "could have's" is that we could have tested the mooring by backing down on it.
We plan to cruise again, and will probably take a mooring again at some point.
I'd like to hear what others do as far as checking moorings ?

We always back down on moorings. But, four of fhe longest weeks of my life were when we left our liability only insured sailboat on a mooring at Dinner Key while we made a necessay trip home. (We have resumed carrying full insurance again, too)

[Wind River]

I can understand backing down on a mooring just as you would do an anchor. It may show the failure that is ready to happen.

In this case backing down would not have shown the inevitable failure. If the weld was broken and the nut had not backed backed off the threads, the failure would have not shown itself. Maybe putting a wrench on the nut and checking for movement on the threads would indicate the weld is still good? As you can see in my pictures, the weld failed under the nut. If I was able to recover the nut, I bet there would have been no evidence that the weld failed by looking at it.

I guess it is best not to have the swivel in the mix, but it is the only means available to keep the mooring lines from twisting up. Change them early and often!

[Paul L]

Originally Posted by Wind River

I can understand backing down on a mooring just as you would do an anchor. It may show the failure that is ready to happen.

In this case backing down would not have shown the inevitable failure. If the weld was broken and the nut had not backed backed off the threads, the failure would have not shown itself. Maybe putting a wrench on the nut and checking for movement on the threads would indicate the weld is still good? As you can see in my pictures, the weld failed under the nut. If I was able to recover the nut, I bet there would have been no evidence that the weld failed by looking at it.

I guess it is best not to have the swivel in the mix, but it is the only means available to keep the mooring lines from twisting up. Change them early and often!

Not sure why you conclude this. If you backed down hard enough the weakened swivel may have given way.

[sparrowhawk1]

On my motorcycle axle nuts there were slots on the "top"(end) of them and a hole in the threads of the axle so you would tighten it, lining up one of the slots with the hole and put a cotter pin through it. I would imagine you could drill a hole through the Nut & Threads at the "top" (end) and put a cotter pin or seizing wire through.
PS I'm so glad I kept reading to find out that the failure is with the nut un- screwing. Thanks Wind River

[sparrowhawk1]

Originally Posted by Paul L

Not sure why you conclude this. If you backed down hard enough the weakened swivel may have given way.

The weld may have failed but the swivel doesn't fail until the nut unscrews so putting force on it will not show the failure. I'm not saying I don't back down on Moorings hard cuz I do.

[arsenelupiga]

another way how moorings fail is they get purposely loosened by some hotheaded locals. This happened to guy next to us. He luckily inspected mooring visually.

I now always inspect and attach boat also to main holder where no moving parts. Backing on mooring better than nothing but dont rely on it. Unscrewed shackle will hold you but digging of boat will get it lose.

And last, always use gps anchor watch !

[Jim Cate]

Well, as posted above, if the failure is due to the nut unscrewing, then drilling and pinning or safety wiring with a monel wire seems a very good idea to me!

Jim

[Wind River]

Originally Posted by Paul L

Not sure why you conclude this. If you backed down hard enough the weakened swivel may have given way.

As Sparrowhawk1 stated:
"The weld may have failed but the swivel doesn't fail until the nut unscrews so putting force on it will not show the failure."

Physically checking the nut for movement may be the only practical way to know if the weld has broken.

As Jim suggests, pinning the nut should alleviate the nut backing off once the weld breaks but I doubt that loose threads will last long in that environment, just delaying the inevitable.

Seem to me replacing a good quality swivel on a regular basis (6 months?) is the best course of action here. I think I paid about $55 for the 3/4" swivel and about the same for a 1" safety shackle to attach my two mooring lines to. The shackle will easily do a year without replacement but you have to keep an eye on the threads on nut and pin as they will corrode allowing the nut to be loose. The safety shackle uses a thinner nut, making this a bigger problem. The cotter pin keeps it from coming off and its easily inspected. Doesn't seem like a lot for a reasonable sense of security if one has to use a swivel.