How I did my mooring.

[Alcyone]

I asked some questions on this forum towards the end of last year about mooring design, and got a lot of good advice. I thought it might be worth 'putting something back' and saying what I ended up doing.

I make no guarantees that this is the best way, or even the correct way, it's just what I did for my boat, with my constraints.

I have a 28ft Cobra sailing boat, weight approx 3.5 tonnes, and the mooring was to be at Dale, Milford Haven, a relatively sheltered anchorage, in tidal waters. I was to do a friend's mooring at the same time.

My constraints were that we live approx 90 miles from the site, and not only had to transport all the components, but had to be able to float them out to the mooring position at high tide, having dropped them off at the bottom of a slip at low tide.

I was limited to 22m total chain length by the harbourmaster. With a 7m (ish) maximum range, I decided to go for 12m ground chain and 10m riser chain. This would give me the best mix of weight on the bottom whilst still allowing for waves etc.

I was fortunate enough to be given 10m of 12mm chain to use as my riser, but bought 12m of 32mm heavy chain for my ground chain from a scrap merchant. It cost £10 per metre and weighed (approx) 7cwt.


I made the concrete blocks at 4cwt. Used some 32mm chain, cut with a grinder and galvanised 1” pipe inserted through the chain inside the blocks as extra strength. I figured 2 men could probably move 4cwt.

I bought a pile of large (1” bar thickness) shackles to link the whole lot together.


Then, the hard work. Load all of the gear into the trailers, transport them to West Wales drop them off at low tide at Dale, then, using lifting bags (I am a diver), move all the components, 1 at a time to our mooring positions, sink them, chain them together and affix the riser chains and buoys.
This took approx 3 days for the two moorings, and cost approx £400 for components and diesel/petrol. It was hard!
We were quoted £6-800 each for a contractor to lay the moorings for us, single concrete block, 10cwt, 3m ground chain and riser. Effectively, we saved about £4-600 each.

Was it worth it? I think so, but I’m in no hurry to do it again!
Hope that may be of use to anyone considering similar.

 

[Searush]

What's the loose floating rope tail for? Strikes me that it's just waiting to wrap around your prop when trying to pick up the bouy.

 

[Alcyone]

What's the loose floating rope tail for? Strikes me that it's just waiting to wrap around your prop when trying to pick up the bouy.

It's my drawing I'm afraid. It's an extra tail, 20mm floating rope, with an eye on it. That's the first thing I pick up. It's actually joined to the riser chain below the swivel, so if the swivel fails and the head buoy comes off (which I've seen), hopefully, the rope will act as a failsafe. The only issue is, it does tend to tangle a bit (I used a similar set up on a borrowed mooring last year) because it is below the swivel, but it only takes a few minutes to untangle, so I'd rather keep it.

 

[neil_s]

For a similar size boat in 5 m at high water, I used a single 400 Kg sinker, 4.5 m of 22 mm long link ground chain and 9 m of 10 mm riser. My sinker has a more 'scientific' shape though - it has sloping sides and a large footprint so that it creates the maximum 'suction' with the sea floor.

Its good to hear others are not frightened off laying their own mooring tackle! Go for it!

Neil

 

[peteK]

I would have the riser coming from the centre of the ground chain with the concrete weights at either end ,as the ground chain is relatively short I would have some slack in it,to allow for wave height.

 

[Searush]

I would have the riser coming from the centre of the ground chain with the concrete weights at either end ,as the ground chain is relatively short I would have some slack in it,to allow for wave height.

His system allows the ground chain to offer the extra needed for big waves. And the weight of it is applied progressively to reduce snatch. I would be perfectly happy with it.

However, I used something similar to what you suggest 30 years ago for a mooring I laid in a narrow estuary channel with big tides & exposed to wind over tide NW'lies over the ebb. I used 2x very large Danforth style anchors.However, it did occasionally snatch & on one particularly bad N/Wly it ripped my strop in half & bent the bow roller (a really chunky s/s one) at right angles.

 

[Alcyone]

I would have the riser coming from the centre of the ground chain with the concrete weights at either end ,as the ground chain is relatively short I would have some slack in it,to allow for wave height.

I did consider that. By breaking my sinker down into 3, for ease of movement, I could have done. I could also have strung the weights out along the ground chain, like (I think) a sentinel. At the end of the day, though, it's a question of how much work, against the returns. The design is far heavier than I was advised by others in the same area.

As an added bonus, there were two cast iron train wheels from a previous mooring there two, so I shackled onto them for good measure! I haven't drawn them, as they were fortuitous, and not part of the design, which I used on two moorings.

Forgot to say that I seized all the shackles with wire and will drop the riser at the end of each season, diving and servicing the chain and shackles as required at the start of the next.

As I said, it's not meant to be a 'this is how you do it' post. It's just that in my 'research' I found that there were many, many thoughts on the subject. These are mine. Hopefully, others may find this useful.

 

[Alcyone]

His system allows the ground chain to offer the extra needed for big waves. And the weight of it is applied progressively to reduce snatch. I would be perfectly happy with it.

However, I used something similar to what you suggest 30 years ago for a mooring I laid in a narrow estuary channel with big tides & exposed to wind over tide NW'lies over the ebb. I used 2x very large Danforth style anchors.However, it did occasionally snatch & on one particularly bad N/Wly it ripped my strop in half & bent the bow roller (a really chunky s/s one) at right angles.

Yes, that's exactly what I thought. Dale faces East, and I've never seen huge waves there (launched Ribs there over many years), but you can get some weather if it blows hard, fetching down the river from Milford.

 

[peteK]

His system allows the ground chain to offer the extra needed for big waves. And the weight of it is applied progressively to reduce snatch. I would be perfectly happy with it.

However, I used something similar to what you suggest 30 years ago for a mooring I laid in a narrow estuary channel with big tides & exposed to wind over tide NW'lies over the ebb. I used 2x very large Danforth style anchors.However, it did occasionally snatch & on one particularly bad N/Wly it ripped my strop in half & bent the bow roller (a really chunky s/s one) at right angles.

Something simalar happened to a friends 22ft westerley at Red wharf bay with no give in the mooring(despite being warned),a north eastely gale coupled with a spring tide actually snapped chain/sampson post cant remember which and the boat was left high and dry at head of bay.

 

[Searush]

PeteK
I know Red Wharf bay well, mostly the bad conditions there don't last that long as the drying banks offer excellent shelter. At least there is plenty of sand & few rocks when they come off their moorings there.

I see you are Wirral based, so you will know my old mooring - at Heswall at the seaward end of the moorings off Morris's boat yard, close to the dog leg in the channel. Again she ended up on the sand, just short of the rough rock sea wall by the bungalows at the end of the lane. She was pulled off on the next tide by digging a channel & laying her anchor to winch her back into the channel.

 

[tabernacleman]

mooring

what persuaded you to go for concrete blocks which are obviously cumbersom and difficult to lay and recover, when lighter and more easily handled anchors are available and can be placed with care without recourse to diving, and I would think a cheaper option,
regards.

 

[peteK]

PeteK
I know Red Wharf bay well, mostly the bad conditions there don't last that long as the drying banks offer excellent shelter. At least there is plenty of sand & few rocks when they come off their moorings there.

I see you are Wirral based, so you will know my old mooring - at Heswall at the seaward end of the moorings off Morris's boat yard, close to the dog leg in the channel. Again she ended up on the sand, just short of the rough rock sea wall by the bungalows at the end of the lane. She was pulled off on the next tide by digging a channel & laying her anchor to winch her back into the channel.

Have kept several boats at Heswall over the years and its a pleasant walk down across the dales of about a mile from my home.But silting channels and strong currents in the gutters has made me seek pastures new ie mooring leaders getting caught around the keels on the flood.

 

[William_H]

moorings

I would have the riser coming from the centre of the ground chain with the concrete weights at either end ,as the ground chain is relatively short I would have some slack in it,to allow for wave height.

I agree the long heavy chain laying along the bottom could be dragged by the boat to a new location. Or put another way the swing radius will be huge. What you want is for the bottom of the lighter chain to be the centre of the mooring. So ideally additional chains and weights from that point to different directions and weights. Often you can find other weights around and old chain or even rope can be used to attach to these to ensure location of the mooring.
I think rope is far better for attaching to the boat as it gives some spring effect.
I didn't understand what the floating rope is for. Certainly you can not attach that to the boat if it is connected under the swivel. Additional ropes above the swivel are good. olewill

 

[Alcyone]

what persuaded you to go for concrete blocks which are obviously cumbersom and difficult to lay and recover, when lighter and more easily handled anchors are available and can be placed with care without recourse to diving, and I would think a cheaper option,
regards.

Well, diving is not a problem to me, and I had most of the material for the concrete blocks, so they were certainly cheaper than anchors. Also, setting an anchor at the end of 12m of 32mm chain would have been difficult.

 

[Alcyone]

I agree the long heavy chain laying along the bottom could be dragged by the boat to a new location. Or put another way the swing radius will be huge. What you want is for the bottom of the lighter chain to be the centre of the mooring. So ideally additional chains and weights from that point to different directions and weights. Often you can find other weights around and old chain or even rope can be used to attach to these to ensure location of the mooring.
I think rope is far better for attaching to the boat as it gives some spring effect.
I didn't understand what the floating rope is for. Certainly you can not attach that to the boat if it is connected under the swivel. Additional ropes above the swivel are good. olewill

The floating rope is a failsafe. I can use it to attach to the boat, even though it is below the swivel - I did so last year, when I was moored way up the Cleddau river, with a fierce switch of direction after slack water. It did occasionally tangle, as I said above, but it was not an issue.

We keep a Rib in Ramsey Sound, as well. Last year a swivel failed on another mooring. That boat, luckily, was found, off Anglesey, head buoy, tails and swivel still attached. By attaching a rope tail below the swivel, I avoid that possibility at least.

I like your idea about the riser being attached to the mooring centre, but we have swing room, given by the maximum chain length specified by the harbourmaster. As for drag, we shall see, but with approx 19cwt ground tackle (and, in my case the additional train wheels I found) I'd be surprised if it moved at Dale.

 

[theoldplucker]

I use two lengths of ground chains shackled side by side to give extra weight and spring. Thought you would have used heavier block than total 12 cwt. I have 1.5 ton granite block for similar size yacht, 28' Merlin, which was £175 to purchase and lay about 4 years ago.

 

[William_H]

Failsafe rope

The floating rope is a failsafe. I can use it to attach to the boat, even though it is below the swivel - I did so last year, when I was moored way up the Cleddau river, with a fierce switch of direction after slack water. It did occasionally tangle, as I said above, but it was not an issue.

Use of the rope attached under the swivel might be OK for short term use ie one or 2 days. But to leave it attached to the boat negates the value of the swivel. I have seen mooring ropes nearly completely unravelled and splices come apart because a swivel was not used or became stuck. Chains become tightly twisted and try to shorten them selves. Each change of wind or tide potentially is another twist in the mooring chain.

Definitely use additional safety ropes for mooring but for long term they must be attached above
the swivel. Keep the swivel at or near the top so you can examine and replace it often. It is the one part you can't double up on. They are reliable but some type have a ball in a cup and you can't see the wear of the ball and cup easily. olewill

 

[Alcyone]

I use two lengths of ground chains shackled side by side to give extra weight and spring. Thought you would have used heavier block than total 12 cwt. I have 1.5 ton granite block for similar size yacht, 28' Merlin, which was £175 to purchase and lay about 4 years ago.

I would have preferred to use heavier weights, and indeed to use a single, rather than three separate, but I did have constraints on what I could physically handle, both for the 90 mile journey and floating it out to the mooring. The other points relating to this are the particular environment, and speaking to other mooring holders in the same area regarding their designs. The other point, of course, is that I did find two train wheels.

Concrete loses up to 40% of it's weight in water, steel/iron, about 15%. Even taking these into account, I still estimate the weight of my ground tackle at around 21cwt.

The two contractors in the area, who presumably are used for insurance purposes by their customers use a 3/4 tonne concrete block, effective weight about 8cwt.

Ulyimately, time will tell how effective this design is. This is where, I feel, being able to dive it regularly is important, for me.

 

[Alcyone]

The floating rope is a failsafe. I can use it to attach to the boat, even though it is below the swivel - I did so last year, when I was moored way up the Cleddau river, with a fierce switch of direction after slack water. It did occasionally tangle, as I said above, but it was not an issue.

Use of the rope attached under the swivel might be OK for short term use ie one or 2 days. But to leave it attached to the boat negates the value of the swivel. I have seen mooring ropes nearly completely unravelled and splices come apart because a swivel was not used or became stuck. Chains become tightly twisted and try to shorten them selves. Each change of wind or tide potentially is another twist in the mooring chain.

Definitely use additional safety ropes for mooring but for long term they must be attached above
the swivel. Keep the swivel at or near the top so you can examine and replace it often. It is the one part you can't double up on. They are reliable but some type have a ball in a cup and you can't see the wear of the ball and cup easily. olewill

Thanks for that, I'll bear that in mind, and check it regularly. As I said, I used a rope below the swivel last year, in a river. It was OK then, but, this is a different site, and the weather may be different, so it's worth watching.

If I remember, maybe I'll dig out this post at the end of teh season and report back on how it performed.

Cheers, all.

 

[fireball]

With the Swivel being the obvious point of failure can I make a suggestion?

You can get mooring buoys that the rise chain passes through the middle of - just a tube through the middle - no joins or anything. You can then finish the chain off with a shackle above the buoy - and attach the swivel to that.
Benefits are:
1) You have fewer joins below the water where you cannot see them
2) Your swivel is clearly visable
3) You can attach directly to the chain quickly if the swivel is in doubt
4) The weight of the chain is taken directly on the buoy - and not through the swivel.

This is how our club moorings are done and I cannot remember the last 'failure' we had - may have been during the 'storm' ... but I wasn't a big boat owner at that point so didn't pay much attention!