laying mooring

[PabloPicasso]

I#ve been on my swining mooring for 5 years in a tidal river port . I inherited the mooring from its previous owner who laid it. He says it is an old safe with a hole cut in the back, a loop of heavy chain passed through, to which is attached the riser chain.

Some of the riser chain links are now wearing thin. the safe is buried far too deep in the mud to reach.

What should I replace this with?
How heavy does the block on the river bed need to be (boat is 4tons approx)
How much will it all cost.
(All of the mooring is my reponsiibility)

 

[alahol2]

If you can get down to the heavy chain then the normal maintenance would be to replace the riser only. Being in the mud normally means that the ground chain/lower chain doesn't rust or wear out anywhere near as fast as the riser.

 

[PabloPicasso]

diver

That is interesting. If I don't need a new sinker replacing the chain would be easier and cheaper. I'll have a check at low water and see what I can see!!

 

[William_H]

Mooring maintenance

I think you need to follow the chain right down to the safe. As said it may be heavier chain that has not had so much movement so not so much wear.
If you can't unearth the safe and chain then the condition of as much of the chain through the safe as you can see is a good indication.
If you have doubts then it may be easier to make sure by adding more chain and weights to the bottom of the riser. The weights can be anything you can get and transport to the site. I have a few old car tires filled with concrete. With 4 in addition to my main weight now very old I feel a bit more secure. I spread them out in different directions from riser. Old anchors are good too.
As a matter of interest the boat next to mine 18ft Keel boat cam adrift. It was found that his mooring weight was a large gear wheel. A chain was passed through the spokes and rim. it was found that the rim itself had rusted away. Now I don't imagine the safe will rust through but you need to check everything.
good luck olewill

 

[stav]

When I was able to enjoy a swinging mooring, alas 20 yrs ago the local boat yard had an old motor boat with a huge winch and could lift up moorings, otherwise I seem to remember pulling the chain tight and having a diver check it (4 to 6m water) and seemed to recall changing just the riser every 3 yrs or so.

If your ground chain and sinker are in really black mud the lack of oxygen will slow the corrosion, if it is on the top of sand it will be quicker.

My sinkers over the years where a giant gear wheel from a crane, lorry engine block an tyres with concrete and reinforcing bars. Only ever changed these as I changed boats.

Good luck with it

 

[ffiill]

Take a look at this booklet from NZ-over there its all leglisated
http://ecan.govt.nz/publications/General/MooringBookletfhmx.pdf

 

[Daydream believer]

I am the clerk to StLawrence Fairway Committee & administer 84 moorings on the river Blackwater ( we have some spare ones next year)
Our design is a concrete sinker sized for the boat( max 30 ft boats) set in to this is a 38 mm chain 1 metre long. This is connected to a riser 19x80 link. With 2 no. 19x22 tested galve shackles. Above this is a 25 mm multiplat riser approx 5 metres long connected each end with single 19x 22 shackles through nylon thimbles. Above that we have a 1.5 metre length of 16x100 link chain then the buoy- normally RB 65 size
The overall length of the set up is 1.5 times depth at high water plus 1 metre for storm surge.
Shackles & thimbles are checked annually & mooring lifted by tug every 3 years for larger boats & 4 years for small boats. Then the chain & shackles are replaced the buoy & multiplatt last years

 

[alahol2]

I am the clerk to StLawrence Fairway Committee & administer 84 moorings on the river Blackwater ( we have some spare ones next year)
Our design is a concrete sinker sized for the boat( max 30 ft boats) set in to this is a 38 mm chain 1 metre long. This is connected to a riser 19x80 link. With 2 no. 19x22 tested galve shackles. Above this is a 25 mm multiplat riser approx 5 metres long connected each end with single 19x 22 shackles through nylon thimbles. Above that we have a 1.5 metre length of 16x100 link chain then the buoy- normally RB 65 size
The overall length of the set up is 1.5 times depth at high water plus 1 metre for storm surge.
Shackles & thimbles are checked annually & mooring lifted by tug every 3 years for larger boats & 4 years for small boats. Then the chain & shackles are replaced the buoy & multiplatt last years

No mention of a swivel? Does this not cause any problems?

 

[Daydream believer]

Our buoys have a centre with a stud on the top. The ring to this swivels on the stud
Never had any problems

 

[ukmctc]

I made mine from an extremely large tractor tyre filled with concrete, then 21mm studlink chain 10 mtrs then seasteel rope riser, put them in four years ago and still working fine holding anything up to 15 ton.

 

[PabloPicasso]

news

Ok so with help of a couple of mates I have succesfully replaced the riser chain on my swinging mooring. At LWspring last wedensday we pulled the old chain and bouy up as far as we could. Then could just see the big lifting ring through which a huge peice of ships chain was double looped.

A local lad in a wetsuit (looking for two other dropped moorings) hopped in ducked under with the end of the chain and passed it back up to us. I shackled it onto itself with a sunstantial shackle and sealed the thread with tek7, and seized the pin with several big cable ties and wire.

Only thing I didn't consider was fitting some annodes. I might re-visit annodes at a later spring, they seem like a sensible idea

 

[William_H]

Anodes on mooring

I am not at all convinced that a sacrificial anode will make any difference on wear on a mooring chain.
The mode of wear is oxidation (rust) which is worn off to allow more oxidation. Rust usually largely protects iron from more rust but bare iron rusts very quickly.
Well done to the OP on fixing his mooring. I would as already suggested added to the mooring. This can reduce the movement and so wear of the buried part of the mooring.
Yes I have seen large iron gear wheels rust right through the perimeter and let a boat go.
Nothing lasts very long down there. good luck olewill

 

[Daydream believer]

Ok so with help of a couple of mates I have succesfully replaced the riser chain on my swinging mooring. At LWspring last wedensday we pulled the old chain and bouy up as far as we could. Then could just see the big lifting ring through which a huge peice of ships chain was double looped.

A local lad in a wetsuit (looking for two other dropped moorings) hopped in ducked under with the end of the chain and passed it back up to us. I shackled it onto itself with a sunstantial shackle and sealed the thread with tek7, and seized the pin with several big cable ties and wire.

Only thing I didn't consider was fitting some annodes. I might re-visit annodes at a later spring, they seem like a sensible idea

I suggest removing the wire as here on the blackwater we find it can cause electrolitic action.
If you renew the chain do npt bother with galvanised as it lasts no longer than plain. The links wear the galvanising off
Re the shackles -we use stockholm tar ( get it from horse tack companies) on the threads . Protects & can be undone ok. On shackles it is normally the thread that wears & the pin fails

 

[Seashoreman]

http://www.hha.co.uk/proxy.asp?proxy_url=library/files/3435D652-B2D5-4F98-8B25-A9C2D05C077F.PDF

Harwich Haven recomendations. Hope this may help.

 

[Spirit of Glenans]

I#ve been on my swining mooring for 5 years in a tidal river port . I inherited the mooring from its previous owner who laid it. He says it is an old safe with a hole cut in the back

I've seen a safe which was broken open in a shop in which I once worked. It was double skinned, each skin about 6-8 mm with in infill of fine sand in between, so it was certainly heavy, but not as strong as it would have been if it was steel right through. I'd imagine a sfe like this would rust through relatively quickly.

 

[vyv_cox]

I've seen a safe which was broken open in a shop in which I once worked. It was double skinned, each skin about 6-8 mm with in infill of fine sand in between, so it was certainly heavy, but not as strong as it would have been if it was steel right through. I'd imagine a sfe like this would rust through relatively quickly.

The one Kevin McCloud used for a wood burner in his woodland cottage had solid steel walls inches thick. Took a thermic lance to cut through it.

 

[jakson]

I have a few old car tires filled with concrete. With 4 in addition to my main weight now very old I feel a bit more secure. I spread them out in different directions from riser. Old anchors are good too.