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dvuyxx 02-16-2013 10:33 AM

Yikes! Mooring System Failure
 
The bad news: Last night, I looked out into our cove to find that our 500 lbs. mooring system was not in its usual location ... in fact, nowhere to be seen.

The good news: Our boat is on the hard for the winter.

So, this mooring ball was installed with a 500 lbs mushroom in 2009. I found the ball still attached to the lighter top chain on nearby shoreline. I dragged it up on land but I haven't examined it closely yet because the sun was setting and it was raining. It looks like it failed at the first swivel at the bottom of the upper chain.

Is less than four years a short life for a mooring system in a protected cove in brackish water? I thought that I would pull, inspect, and or replace after 5 years being on the cautious side.

I have to forensically go back and examine what we put down there. But was there anything that we could have done incorrectly here?

This is similar to what we had in our setup:
http://www.easternmarine.com/media/d...agram.7717.jpg

Lake Superior Sailor 02-16-2013 10:41 AM

Re: Yikes! Mooring System Failure
 
Not all chain is created of the same quallity so I would start by checking what you used and who made it! ...Dale

chef2sail 02-16-2013 10:49 AM

Re: Yikes! Mooring System Failure
 
The swivels are usually the weakest points...Im interested to see it thats where it failed. Why not just use two shackless to connect heavy and light chain?

This may seem dumb, but what not use heavy chain for the whole system?

Where actually is your mooring...on the Magothy? Which cove or creek?

dvuyxx 02-16-2013 11:02 AM

Re: Yikes! Mooring System Failure
 
We're on upper Round Bay, Severn River.

My understanding is that if you don't have swivels the whole system binds and fouls. Also if you have heavy chain on the upper part of the system it is too much downward pull on the ball.

tommays 02-16-2013 12:05 PM

Re: Yikes! Mooring System Failure
 
In my area they are hauled and inspected annually

dvuyxx 02-16-2013 12:25 PM

Re: Yikes! Mooring System Failure
 
Are those municipal/organized or commercial moorings or private ones too that are pulled each year?

Maine Sail 02-16-2013 12:27 PM

Re: Yikes! Mooring System Failure
 
Quote:

Originally Posted by dvuyxx (Post 990898)
The bad news: Last night, I looked out into our cove to find that our 500 lbs. mooring system was not in its usual location ... in fact, nowhere to be seen.

The good news: Our boat is on the hard for the winter.

So, this mooring ball was installed with a 500 lbs mushroom in 2009. I found the ball still attached to the lighter top chain on nearby shoreline. I dragged it up on land but I haven't examined it closely yet because the sun was setting and it was raining. It looks like it failed at the first swivel at the bottom of the upper chain.

Is less than four years a short life for a mooring system in a protected cove in brackish water? I thought that I would pull, inspect, and or replace after 5 years being on the cautious side.

I have to forensically go back and examine what we put down there. But was there anything that we could have done incorrectly here?

This is similar to what we had in our setup:
http://www.easternmarine.com/media/d...agram.7717.jpg

Some thoughts...


* I would not place a swivel anywhere but at the ball so it can be expected regularly.. SWIVELS MUST BE LARGE!!!

* I would not install any swivel smaller than 3/4". I use an 1 1/4" swivel on a 36 footer. My top chain is 3/4" long link mooring chain and my bottom chain is 1 1/2" US Navy chain at nearly 22 pounds per foot.

* The chain and swivel should be "winterized" by installing a winter spar which allows the chain to be dropped to the bottom, stop wear and sit in the low oxygen mud bottom....

* Moorings should be inspected yearly or bi-yearly at a minimum. Top chain should really not be any smaller than 5/8 and really that is tiny chain for a permanent mooring.....

* Swivels are the highest wear item therefore they need to be directly below the ball. They should also be VERY LARGE so as they wear they don't wear faster than the top chain.

On a permanent mooring a top swivel is usually very necessary especially in areas of high tidal ranges as the boat swings around, and around, and around sometimes for weeks depending upon usage. Do this enough and the chain twists and shortens to 1:1 scope and sucks the ball under. If a storm comes up you simply un-set the mooring and drag it or shock load the gear until you have a failure.

The problem with the vast majority of moorings is they are grossly under designed. Swivels are too small, placed in the wrong locations or are of an unsuitable design.

Chain is also almost always far to light/small for storm purposes and "shock loads" the gear.

At a minimum for our boat (36') my design criteria is:

*8000 Pounds of granite (actual storm mooring is 9600 pounds), 500 pound mushroom (min) or screw mooring
*USCG/USN bottom chain (1 1/2" X 22 pounds per foot) to 1.5 X Depth
*3/4" Top chain to 1X depth
*1" Swivel MINIMUM directly below ball (actual is 1 1/4")
*Dual unequal length polyester pendants with Vectran storm snugs added to go over the chocks in storms.

I use a 1 1/4" swivel for our CS-36. Our town requires a top swivel on moorings as part of the local ordinance.

This is my eye to eye swivel for a 36 footer.
Swivel Eye To Eye 1 1/4"" Galvanized Made In USA

This is the bottom chain on one of our moorings, the lighter of the two. My storm mooring is the type with the cross bars in the links.
http://www.pbase.com/mainecruising/image/92683374.jpg

Maine Sail 02-16-2013 12:33 PM

Re: Yikes! Mooring System Failure
 
Quote:

Originally Posted by tommays (Post 990925)
In my area they are hauled and inspected annually

Unless these are all deadweight moorings this is actually poor form dictated by a town without not much of a clue about proper mooring protocol. Yes the chain can be inspected but the moorings are all "barely set" which creates even lots of potential for danger in storms.

Mushroom and pyramid style moorings, and even dead weight moorings, can take months to properly set. Every time you un-set one you open up your potential for dragging the mooring because it is not yet set well. Inspections ideally should be done by town certified divers.

I will not let anyone un-set my mushroom mooring. It is 6' into the bottom..... That type of set takes a few years to attain....

chef2sail 02-16-2013 12:49 PM

Re: Yikes! Mooring System Failure
 
Quote:

Originally Posted by Maine Sail (Post 990932)
Some thoughts...


* I would not place a swivel anywhere but at the ball so it can be expected regularly.. SWIVELS MUST BE LARGE!!!

* I would not install any swivel smaller than 3/4". I use an 1 1/4" swivel on a 36 footer. My top chain is 3/4" long link mooring chain and my bottom chain is 1 1/2" US Navy chain at nearly 22 pounds per foot.

* The chain and swivel should be "winterized" by installing a winter spar which allows the chain to be dropped to the bottom, stop wear and sit in the low oxygen mud bottom....

* Moorings should be inspected yearly or bi-yearly at a minimum. Top chain should really not be any smaller than 5/8 and really that is tiny chain for a permanent mooring.....

* Swivels are the highest wear item therefore they need to be directly below the ball. They should also be VERY LARGE so as they wear they don't wear faster than the top chain.

On a permanent mooring a top swivel is usually very necessary especially in areas of high tidal ranges as the boat swings around, and around, and around sometimes for weeks depending upon usage. Do this enough and the chain twists and shortens to 1:1 scope and sucks the ball under. If a storm comes up you simply un-set the mooring and drag it or shock load the gear until you have a failure.

The problem with the vast majority of moorings is they are grossly under designed. Swivels are too small, placed in the wrong locations or are of an unsuitable design.

Chain is also almost always far to light/small for storm purposes and "shock loads" the gear.

At a minimum for our boat (36') my design criteria is:

*8000 Pounds of granite (actual storm mooring is 9600 pounds), 500 pound mushroom (min) or screw mooring
*USCG/USN bottom chain (1 1/2" X 22 pounds per foot) to 1.5 X Depth
*3/4" Top chain to 1X depth
*1" Swivel MINIMUM directly below ball (actual is 1 1/4")
*Dual unequal length polyester pendants with Vectran storm snugs added to go over the chocks in storms.

I use a 1 1/4" swivel for our CS-36. Our town requires a top swivel on moorings as part of the local ordinance.

This is my eye to eye swivel for a 36 footer.
Swivel Eye To Eye 1 1/4"" Galvanized Made In USA

This is the bottom chain on one of our moorings, the lighter of the two. My storm mooring is the type with the cross bars in the links.
http://www.pbase.com/mainecruising/image/92683374.jpg

Gotcha on the need for swivel somewhere as it makes sense in "winding up the chain". So you only need the top one so you can inspect it.

Size of chain is impressive to say the least.

BarryL 02-16-2013 01:25 PM

Re: Yikes! Mooring System Failure
 
Quote:

Originally Posted by Maine Sail (Post 990933)
Unless these are all deadweight moorings this is actually poor form dictated by a town without not much of a clue about proper mooring protocol. Yes the chain can be inspected but the moorings are all "barely set" which creates even lots of potential for danger in storms.

Hey,

Here in the north shore of Long Island (south side of the LI Sound), the towns regulate moorings. I own my mooring gear but need to purchase a mooring permit each year. The mooring can be placed in the spring and must be hauled by December. The upside is that the place that drops and hauls my mooring also inspects it and replaces components as required.

Barry


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