ground chain winding?

[GordMay]

FWIW: The preferred method, when making a shackle-to-shackle connection [to centre the load & gain freedom of motion], is connecting bow to bow, or bow to pin. Connecting pin to pin is never advisable, as this may create a point load.

[Kettlewell]

Same for the rope, but my general guess is that the rope has a far lower torque requirement than the chain when developing a twist.

Yep, I've seen mooring pendants get all hockled up, sometimes to the point they drastically shorten the line. These problems with the chain and line getting twisted generally don't occur if the boat is removed from the mooring once in awhile.

[Morris Wilson]

I think the OP is talking about a mooring buoy. Like a previous poster said you need to release from the mooring more often to let it straighten out. I was anchored in a sheltered bay in British Columbia Canada for several years and there were private moorings there as well. the combination of 16ft. tides and winds steered by mountains often caused same direction swivelling for long periods. Boats must be untied once in a while for everything to right itself.

[Shaneesprit]

Who puts the swivel at the bottom?
Surely put the swivel at the top under the mooring Buoy.
You did say “Ground Chain” which I was a little confused about, for me the ground chain is a very heavy short section of chain that goes from the Buoy to the riser chain it should never swivel and rarely if ever leave the bottom.

and yes chains can be shorted my old mooring, the boat would round in the same direction at least twice a day, my current mooring has double tides so could in theory go around 4 times a day but I don’t think it does.

If you check yearly and don’t use cheap Chinese parts you will be ok. I once had a shackle in just a few months.

[jakkum]

It happened to me on the River going to Ipswich East Coast of the UK My Ship 200 Ton Sailing fishing vessel and a big Morning mooring A Big floating tank
Middle of the night I got out just to check and so that we had moved with the tank
So I started the engine and moved to save spot and put my own Anker Down
Next Day a heard in the Pub at pin Mill that Dis happened about once a month
Chain shortend because of Turning of the moaring in the current and of course for my ship it was lot Easy that we small s*** to Move the lot
Somewhirrelse on the East Coast were few tankers late up and you could See that the ancer Change where really Turn up the two anchers down but that was a mess

[gulfislandfred]

I have had a permanent mooring in Degnen Bay, Gabriola Island, BC, for more than 20 years. Depth varies from about 20 feet to about 35 feet, due to tide.


Tidal action and wind makes moored boats in this bay swing in circles, often full circle, twice a day.


The following is actual experience, not speculation, opinion, or the result of reading articles by 'experts'.



I have replaced my mooring rode several times over the years. I have (as have most others in the bay, as we gain experience, and speak to others with moorings, and the divers who service them) gradually used less chain, and more rope.



I now use just enough chain to keep the rope off the bottom. So far, I have never had any significant chafe on my rope (3/4 in green 'polysteel', which floats)


My diver, who services many of the moorings in the bay, reports that he has never seen a chafe issue with mooring rode below the water. He has, rarely seen chafe issues when mooring lines are attached at the top end, in such a way that the mooring rode rubs against another line, or a part of the moored vessel.



I have a diver inspect the mooring annually.



I have replaced my chain every three to five years, as it rusts, especially where the links rub against each other. I started with 3/8" galvanized chain, which lasted for two years. It might have been OK for a third year, but wear was significant, and I had acquired a 37 foot Trawler, so I replaced with 1/2". That lasted three of four years, if I remember correctly.


Three years ago, I installed one inch galvanized chain (cost $10/foot, used 7 feet.) So far, the diver reports no appreciable wear.


I have used galvanized swivels of size appropriate to the chain size, at the lower end of the rope, and the top, where the swivel is out of the water.
I have never had a swivel function for more than a few months if it was submerged. Swivels at the top of the rode mostly work well, except when the float at the top gets tangled with mooring lines from vessels moored to the float, which can sink (the line, not the vessel), and wrap around the line under the float.


My current system is the 1" chain, with a spliced eye and shackle on the 3/4 line. There is a small commercial fishing net float tied to the rode/line, about 10 feet up, to keep the line more or less off the bottom. The line goes through a hole in the centre of the mooring float, spliced to a plastic thimble, then galvanized swivel, then a galvanized ring. Boats (sometimes I tie up two boats, rafted) are moored to the ring.


I never use stainless steel tie wire, shackles, or swivels anywhere on an anchor system that uses galvanized parts. I use doubled plastic 'zip ties' to mouse my shackles or galvanized cotter pins, if appropriate.

[Kettlewell]

I have had a permanent mooring in Degnen Bay, Gabriola Island, BC, for more than 20 years. Depth varies from about 20 feet to about 35 feet, due to tide.

Good report. Here in New England most harbors have detailed requirements of exactly what you can and can't use for a mooring, and many enforce those rules. Most require an inspection at least every two years, and some yearly, by a professional and qualified mooring repair person. In many harbors there is a list of permitted vendors. I really like the type of mooring described above, where it is more like an anchoring system with rope allowing the chain to rest on the bottom when not in use, and just a small float at the top to allow you to retrieve the rope. It is just not permitted in most harbors. Typical NE requirements are for a very large block or mushroom, very heavy bottom chain, then a lighter chain that goes all the way to the buoy, then a maximum of 15 feet of rope pendant to the boat. Not everyone uses a swivel, but when they do it is usually between the massive bottom chain and the top chain. https://www.westmarine.com/west-advi...t-Mooring.html

https://www.tisburyma.gov/sites/g/fi...e_document.pdf

[gulfislandfred]

Thanks, Kettlewell,


It's nice to be where a system has evolved over time, and lots of smart people have tried different ideas.
We are, so far, unregulated in our mooring systems. There is some regulation, to keep channels open so other boats can come and go. We do have boats break loose, or drag inadequate mooring anchors around the bay in winter storms.
I like the free and sometimes chaotic system here. There is always pressure for more regulation. Fortunately, the jurisdictions overlap, and gatekeepers are reluctant to get involved - Scant benefit and large potential for liability.



One small correction. The top float is almost 2 feet diameter, with a 3 inch hole up the centre. It's foam filled semi hard plastic. Quite durable, and not as unfriendly to boat hulls as metal.

The main mooring rode comes up through the hole, with swivel, and ends in a four inch galvanized ring (big enough so it can't fall through the centre hole.


Some people pull the rode up through the hole, and secure the ring close to their boat. Others use a pendant from the ring to their mooring cleat.



The small float is lashed to the side of the mooring line a few feet off the bottom, just to help the floating like lift a bit.

[Kettlewell]

The method I really like is only used a few places. Heavy ground chain leads to a rope rode that terminates in an eye that goes over your mooring cleat. A small lobster float is attached to this eye with a light line so when you drop the mooring the entire mooring line and chain is on the bottom where it grows a lot less crud, doesn't corrode anywhere near as badly, is not subject to UV, and is unlikely to be damaged by others driving over it. The boat lies more like at anchor and if you get wind against current there is no mooring buoy to bang against your boat.

[gulfislandfred]

Good system. One would need to add a swivel here. I had no swivel for a while, and the boats (two at the time) spun so much that it unlayed the three strand when I was away for a couple of months.

[Djarraluda]

Originally Posted by Pentos

Has anyone heard of a swing-mooring ground chain "winding" around itself thereby shortening the overall mooring line?

I imagine it's possible if the swivel fails to turn for some reason.
Perhaps if the water was too shallow and the chain including the swivel lay on the bottom?..

Back in the 1970s, I laid a mooring for my first boat and managed to get the riding scope caught under the ground chain, so the swivel could not turn. 1 week later, yes the scope had now pulled the ball under the water.

I borrowed a bigger boat (mine was an 18ft clinker built centreboard) and relaid the mooring and all was well afterwards. I could lift the ground chain to inspect /replace bits annually after that.

Nowadays, most areas insist on a so-called "professional" mooring check annually so it is over to the contractors who have a barge and crane. Strangely, it is the unused moorings with junk boats left sitting where boats break free in a storm - generally due to the swivel failing.
Roger

[Kettlewell]

Strangely, it is the unused moorings with junk boats left sitting where boats break free in a storm - generally due to the swivel failing.

I've mostly kept my boat on a floating mooring for many decades when not cruising fulltime and I've seen a lot of boats break free from moorings and it is almost always due to failure of their rope pendant to the mooring, usually due to chafe or neglect. One common failure mode is someone puts dual pendants on a ball type mooring and they tangle under the mooring, chafing on the chain and large shackle with sharp cotter pin there. Sometimes the dual pendant folks just keep winding up the pendants around and around the chain until the twisted mess is nearly straight down. Another failure mode is chafe where the line leads over a sharp deck edge or toe rail. I've seen big boats break free due to too small pendants during storms.

[GordMay]

Moorings Failure Mode Analysis Root Cause: Following Problems have caused failure of MBC* Moorings.
. Undersize Chain,
. Worn Chain Re-used
. Used Wrong Type Shackle or Swivel,
. Did Not Use Specified Seizing Wire.
. Poor quality and/or undersized Nylon Pennant failed in storm.
. Did Not Splice Tight to Thimble - seizing securing pennant to thimble failed, pennant chafed through
. Inadequate, poorly maintained chafe gear caused pennant to wear through.
. Mushroom not tipped.
. Undersize Mushroom,

* Excerpted from the Monmouth Boat Club “Moorings Booklet” (NLA)

➥ https://www.cruisersforum.com/galler...r&imageuser=79

[Kettlewell]

Moorings Failure Mode Analysis Root Cause: Following Problems have caused failure of MBC* Moorings.

Thanks Gord! Since most of my longterm mooring rentals have been in New England I have had my boat attached to moorings that were required by local law to meet certain specifications and where required inspections were done by professionals. That's not to say that accidents don't happen due to chain and swivel neglect, but I have watched many annual inspections and seen some of the routine bills for replacement of parts. This is one huge reason why I hate being forced to pick up a rental mooring in some places of unknown construction and maintenance. Also, some locales require mooring practices that are unsafe: too short a scope, inadequate ground tackle, improper pendant attachments, dual pendants, etc.