Anchor instead of mooring weight

30boat

30boat

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I need to lay another mooring because my buoy ruptured and sank and nobody can find the huge concrete lump that's down there.Instead of making another I was thinking of welding up a large, say 50kg,anchor based on the latest generation designs.At the risk of having Craig threaten me with his lawyers again I would be using the basic concept behind Rocnas Bugels and Spades etc in designing my anchor.My reasoning is that being oversize and effective it would either not lift out with changes of direction of pull, or if it happened,reset itself quickly. Good idea?It would also be a lot easier to lift annually for inspection.
 
How can no one find the old mooring? Surely a big concrete block, with a large length of chain and a burst buoy all lying on the sea bed where the mooring was would be piss easy for a diver to find.
 
Hopefully you will be able to find your old mooring again - or is the visibility very poor generally where the mooring is?

If no go, then why not fabricate your own mooring anchor - go for it!
The RNLI use Seaboard mooring anchors, ranging in size from 100 kg up to 500 kg - these anchors look a bit like a hard chine (rather than with curves) Bruce, but without the 'wings' on the fluke. They also have a stock (like the old fisherman type anchors).
In fact the Seaboard anchors are similar in shape to these Bosun anchors from Gaelforce (who apparently bought out Seaboard about 12 years ago) : -
http://www.gaelforcemarine.co.uk/Anchors-and-Mooring/Anchors/Bosun-Boat-Anchor/
except that they only have one fluke.
The angle of the fluke to the shank is important - I measured a Seaboard anchor once, and it was 22 degrees (and Danforths are about the same).
You would have to be careful when laying the anchor to ensure that it is lowered down so that the fluke will dig in - if it lands 'upside down' the stock will stop it from digging in.

I drew up a plan for a friend for a modified type of Seaboard mooring anchor, using some scrap plate and I beam sections that he had knocking around, but he hasn't built it yet - he intends to fabricate one for his 28' fishing launch. The estimated weight is about 50 kg.
 
I can't claim to be an expert, but every mooring that I have seen that used anchors has had two or three.

The last one I laid involved two anchors facing each other about 50 ft apart. They wern't very large but were linked by very heavy chain. The, much lighter, riser chain was on a swivel in the middle if this link.

I have also seen three anchors used, linked 120 degrees apart to a swivel for the riser.
 
davidej said:
I can't claim to be an expert, but every mooring that I have seen that used anchors has had two or three.

The last one I laid involved two anchors facing each other about 50 ft apart. They wern't very large but were linked by very heavy chain. The, much lighter, riser chain was on a swivel in the middle if this link.

I have also seen three anchors used, linked 120 degrees apart to a swivel for the riser.
Click to expand...

The link shows the requirements that Harwich Harbour Authority require and as davidej says, if you use anchors then they say you need 2 of them.

http://www.hha.co.uk/proxy.php?proxy_url=library/files/3435D652-B2D5-4F98-8B25-A9C2D05C077F.PDF
 
I wouldn't want to rely on a single anchor moving and resetting on each turn of the tide. Hence the multiple anchor approach, where you hang from whichever one is facing the right way, and don't move them.

Pete
 
Woodlouse said:
How can no one find the old mooring? Surely a big concrete block, with a large length of chain and a burst buoy all lying on the sea bed where the mooring was would be piss easy for a diver to find.
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Well - dunno about p. easy, as the vis might be next to zero, but locating the block would be my 1st choice too.

Thought 1: it's gonna be in shallow water, so a hookah rig is all that's required, or a tank of air and stay down all day ...
If there's some vis, then stake out the area using a bundle of garden canes - maybe with little plastic flags on top - so that you don't keep re-searching areas already covered, and simply keep expanding the search area until you find it.
If it really is zero vis, then heavier sticks with light line stretched between 'em might be a better way to go.

Thought 2: it might also be worth running a depth sounder over the area in the hope that you get a decent reflection from the concrete (a propeller-type sounder would be better than digital).

Thought 3: if you're feeling lazy, offer the local SCUBA club something tempting on a no-find, no-pay basis. In my experience they love a challenge, and something more interesting to do than simply looking at fishes. And - a sea-bed search would be good experience for the trainees.
 
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electrosys said:
Well - dunno about p. easy, as the vis might be next to zero, but locating the block would be my 1st choice too.
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Would it be worth trying to grapple for it? There must be a fair length of chain and stuff lying on the bottom to hook into. Do it at low tide so there's plenty of slack as it's pulled to the surface.

electrosys said:
Thought 3: if you're feeling lazy, offer the local SCUBA club something tempting on a no-find, no-pay basis. In my experience they love a challenge, and something more interesting to do than simply looking at fishes. And - a sea-bed search would be good experience for the trainees.
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Yep - always struck me how the BSAC training books had extensive coverage of useful underwater tasks like searches, salvage, and cutting ropes off props (as well as stuff now regarded as naughty like how to hack portholes out of wrecks). PADI by comparison didn't go beyond "go down, look at fish, come up". I guess the "look at fish" was a lot less interesting in UK waters :-)

Pete
 
prv said:
Would it be worth trying to grapple for it? There must be a fair length of chain and stuff lying on the bottom to hook into. Do it at low tide so there's plenty of slack as it's pulled to the surface.



Yep - always struck me how the BSAC training books had extensive coverage of useful underwater tasks like searches, salvage, and cutting ropes off props (as well as stuff now regarded as naughty like how to hack portholes out of wrecks). PADI by comparison didn't go beyond "go down, look at fish, come up". I guess the "look at fish" was a lot less interesting in UK waters :-)

Pete
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I tried everything in my power to find it but the area is fast silting up as there is a small river flowing into the mooring area and it has rained a lot lately.For that reason visibility is zero and the local diver says we have to wait until the weather improves but by then the whole lot may be buried deep in the silt.There are some great links above which encourage me to make two or three anchors that I can lay there.It'll still be cheaper than making a concrete mooring.
 
30boat said:
Mushroom anchors are the thing but they have to be dropped into a hole in the bottom.That's sometimes done with a high pressure hose ,not very pratical unfortunately.
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Yes but mushroom anchors were in use in the 19th century, i.e. long before high-pressure hoses were around. So there must be a simpler way of setting them
 
parsifal said:
Yes but mushroom anchors were in use in the 19th century, i.e. long before high-pressure hoses were around. So there must be a simpler way of setting them
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My 1950s American seamanship tome advises just plonking them on a suitable seabed then leaving them for some months to dig themselves in. Ideally over a winter so storms can stir the silt up.

Pete
 
Moorings

The simplest way to search for anything under water with SCUBA is to drop a weight with a light rope at the point of best guess. Then dive down to the weight and using the line kept tight swim in a circle around the weight. (searching of course) Use a compass to determine when you have done a full circle. Then move out along the line a distance commensurate with visibility. Do another circle then move out further.
You will have eventually searched an area centred on best guess of radius equal to the rope length.

As said moorings are best with 2 or more anchors. However this means it will be very difficult to lift the mooring for inspection so best for inspection by diving. Anchors for this purpose are easiest made in fisherman style with or without a stock and one fluke if they can be placed by diver.

I think a one anchor mooring would involve a lot of movement of the anchor and chain (with attendant wear) unless the anchor and chain were so heavy that they did not normally move ie only in worst storm.
good luck olewill
 
Woodlouse said:
How can no one find the old mooring? Surely a big concrete block, with a large length of chain and a burst buoy all lying on the sea bed where the mooring was would be piss easy for a diver to find.
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Next time make the exact mooring spot a waypoint in the GPS, that way your serch is limited to 15 feet or so, depending on the accuracy of the GPS. (14 feet accuracy is the best I've seen on my GPS, half a boat length).

A grapnel of sufficient weight over that small area should find it or the chain. I found mine after 4 grapnel draggings over the waypoint. Took about 10 minutes, 5 metres deep, no vis, all done by me steering the yacht, friend with grapnel on the bow. After leaving it alone for a month, it took ten minutes over the waypoint.

If not wise now, you will be for next time.
 
barnaclephill said:
Next time make the exact mooring spot a waypoint in the GPS, that way your serch is limited to 15 feet or so, depending on the accuracy of the GPS. (14 feet accuracy is the best I've seen on my GPS, half a boat length).
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Better still, two intersecting transits. Accurate to within inches (as long as you remember the transits - write them down!)
 
prv said:
My 1950s American seamanship tome advises just plonking them on a suitable seabed then leaving them for some months to dig themselves in. Ideally over a winter so storms can stir the silt up.

Pete
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I found another method described on an American website, it says let go the mushroom anchor on the required spot from a boat with an engine and circle around it a few times so it digs itself in! (presumably this should be done at slack water)
 
Having conducted searches for lost moorings by diving in the past, I can vouch for the fact that they can be very, very difficult to find, even when the owner of the mooring can provide you with a good estimate of where the thing used to be. The biggest problem is the state of the bottom, which in this case sounds like mud or silt: once you arrive at the bottom, if there's enough current to keep the water clear, there's too much movement to conduct a search without getting swept off the location. If there's no current, the water quickly becomes so murkey that you're reduced to conducting a finger tip search, which is not an easy option.....

The local diver being unwilling to dive until the better weather arrives in spring is probably being very sensible. The only option to find it is to go to the local BSAC club (find the branch secretary by visiting the club website at www.basc.co.uk) and see if they'd like a winter challenge. It's just the sort of exercise for a Dive Leader course; lots of planning and a real challenge to boot.

Otherwise, 2 anchors aligned to the main current flows, linked by chain and a swivel to the riser is the way to go in replacing your mooring.
 
Possibly not much use to the op, but from watching here's how to lay a mooring on the cheap. If you are up a muddy river in brazil anyway. These were slowly being installed for boats moored stern or bows to med style against a pontoon rather than have to anchor.

Dig a hole in the river bank about 1m3 at low water and fill it full of concrete with a ring on top.
Low water a few days later when you get round to it build a raft out of any old bits of wood and plastic cans lying around.
Next high water swim it out to where you want to be with a mask and snorkle then cut away the bits of string holding the raft together until it goes glug.
Next day stick a cheap workshop air compresser on a raft with power cord drifting back to pontoon so the local kid can dive with a diving regulator pluged into the compresser and get shouted at each time he comes back up without being able to free the yacht anchor chain next door which is stuck under the concrete block.
Somehow it all works in the end.

is there enough tide where you are to make your own?
 
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