How are swinging mooring checked?

Sneaky Pete

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The swinging mooring is due to be checked in the next few weeks. The mooring is for 1 boat only and uses 2 mushrooms a chain onto a riser in about 10m of water. What I would like to know is how long it usually takes to check the mooring and what is involved in the check. Is the mooring lifted checked and then re-set or what?
 
It depends on what equipment you can throw at it.
A suitably equipped vessel could haul up the whole lot and check everything, shouldn't take long, a mate got several done like this in a day to spread the cost. The downside is that you lose the benefit of the anchors having had time to bed in really well.
Alternatively, you get a diver to check everything that isn't buried in the mud, which can be much cheaper if you know someone, and leaves everything undisturbed. I think it took about half an hour or less when I got a mate to dive my mooring.
 
The swinging mooring is due to be checked in the next few weeks. The mooring is for 1 boat only and uses 2 mushrooms a chain onto a riser in about 10m of water. What I would like to know is how long it usually takes to check the mooring and what is involved in the check. Is the mooring lifted checked and then re-set or what?


Our moorings consist of a concrete sinker with a length ( 12ft IIRC) of heavy (1") chain cast in. A lighter riser chain ( 3/8" or 1/2") is shacked to that. Every year the riser is hauled up and inspected replaced when necessary and the shackle(s) renewed. I think the sinkers and heavy chains are routinely replaced at some established interval based on experience. The annual check only takes a few minutes. Never done it but sat on the boat while its been done.

Obviously replacing the sinkers and heavy chains is a big job as each has to be cast on shore and taken out to be laid .


The yard has a moorings barge with a hand operated winch that is used for both regular inspections and laying new sinkers/ recovering old sinkers

We are in shallow water, infact most dry at LW springs, which helps
 
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Last spring I was lucky enough to go out on a moorings inspection work boat boat in NW Scotland.

They pulled the buoy, swivel and first few (4?) meters of riser up with a hiab and cleaned it all off, then looked at the chain, shackles, swivels etc and recorded the metal thicknesses using a micrometer, and replaced any bits below spec and renewed any shackle mousings needing attention.

Then a diver in a dry-suit went down with a notebook and plastic vernier calipers and came back up with a report; leading to some debate and occasional replacement of shackles below the surface.

So the part in the mud wasn't disturbed, 'just' the riser and its attachment to ground chain. But I was told that - at least in that place - the corrosion on the risers is extremely rapid and aggressive but the ground chains in the anaerobic mud lasts pretty much for ever.

The cost was shared between us mooring owners: call out divided by number of us, and time on a more or less pro-rata basis depending on time spent on each mooring, materials extra. In all it was a pretty comprehensive, professional and impressive exercise.
 
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I am part of an association and the mooring although all separate, not connected, are checked hopefully at the same time. The person doing the work has a barge work boat with a hiab arm for lifting so I am assuming it will be the riser chain and associated parts and not the entire mooring that will be lifted for inspection. I don’t think this bloke does much in the way of underwater diving though. Thanks for the comments.
 
I imagine that your mooring is maintained by Neil Cunningham. He a top bloke and has looked after my mooring ever since he laid it more than 10 years ago. I seem to remember that he'd just clean and check the top of the riser one year and then dive on the mooring the following year to check the bottom. Depending on condition, he used to lift it every 3-4 years (I think), carry out major replacements and re-lay.

Not certain if that's what he still does but he's very reliable and does a good job. If he laid the mooring then he'll have a note of what need to be checked/replaced and I imagine he'll dive on it to check if he hasn't worked on it before.
 
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The swinging mooring is due to be checked in the next few weeks. The mooring is for 1 boat only and uses 2 mushrooms a chain onto a riser in about 10m of water. What I would like to know is how long it usually takes to check the mooring and what is involved in the check. Is the mooring lifted checked and then re-set or what?

Mine is simpler - just some a BFO chain riser and a railway wheel at the bottom. The chap who inspects it just heaves the whole jing-bang up witha crane, has a look and, if it's OK, puts it back. I presume it's a bit harder with two anchors.
 
I've just asked the boatyard to inspect mine before the boat gets launched. As far as I know he just lifts the riser chain and checks the swivels and rope etc. Usually only a small charge but a couple years ago it was a lot more as he replaced the riser, rope and shackles and swivel and the buoy which had deflated.
 
I belong to a Sailing Club with many deep water moorings including mine these are lifted out complete with anchors this is done by all mooring holders with the club barge then taken ashore at the end of the season (November ) Fully inspected by an mooring officer before relaying April/May .
I understand this is to comply with the clubs Insurance plus my own Insurance wanted full details of all mooring equipment /Chain /Anchors.
This is on the River Blackwater which can be quite exposed, boats which have drying mooring self inspect at low water.
The swinging mooring is due to be checked in the next few weeks. The mooring is for 1 boat only and uses 2 mushrooms a chain onto a riser in about 10m of water. What I would like to know is how long it usually takes to check the mooring and what is involved in the check. Is the mooring lifted checked and then re-set or what?
 
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