Advice on use of the mooring raft.

This is a guide concerning safe use of the raft for checking and maintaining moorings. It is aimed at those without experience of using the raft but there may be some usefull information for all.

Health and safety:
1. Consider conditions. If wind and sea state is excessive the raft is difficult to manouvre.
The chain block is likely to,swing about with potential for injury- these conditions are to be avoided. Working on the raft becomes difficult once wind speeds are into double figures.
2.Do not overload the raft. Max of 4 people.
3Wear life jacket or buoyancy aid.
4.Consider wearing a hard hat, available from the club hut. it’s very easy to bang your head on the framework.
5Wear gloves, appropriate clothing and protective footwear.
6 Wear eye protection when cutting with disc cutter.
6. Always use the vice if cutting chain, making sure you are securely positioned.
7. Let the lifting gear do the work, when the hook needs to be repositioned use the quick -release swinging arm to hold the chain. Do not support the chain by positioning a bar through the links across the hulls. This could potentially sink the raft on a rising tide. It is very difficult to remove the bar once the chain becomes taught.
8. Take care to keep tools, new and old mooring materials out of the way.
9. Take care when moving about the raft, maintain the raft’s balance when underway.
10. Ideally work with others.

Outboard.
A 2-3 hp outboard will drive the raft in ideal conditions. This should be placed on the rearmost crossmember. A safety leash to prevent loss overboard is recommended.
Two such outboards work well for more speed and if conditions are a little windier.

Recommended equipment.
Buoys, chain, shackles, swivels, and seizing wire are available from the mooring master.
A battery operated disc cutter is available from the mooring master.
Knife, Hammer, hacksaw, wire cutters, pliers and a crow bar are often useful. Zip ties can be used instead of seizing wire if preferred.

Checking a mooring for wear with the tide in.

A mooring should be checked as far down as possible without the chain going taut and pulling down the raft. Usually a section of chain is reached that is unworn with mud sticking to it. There is nothing to be gained by going deeper.

Approach the mooring upwind and allow buoy to go between the hulls to the pulley. At this stage it is usually quite easy to manhandle the buoy onto one of the decks along with some of the chain.
Then attach the hook low down and haul up in stages, always using the quick release arm to hold the chain when repositioning the hook. The hook sometimes jams in the the chain link, a tap with the hammer should free it, if allowed to go slack. Do not wind the hook so high that it jams at the block.
If the raft starts to go down in the water you’ve gone too far down!

Check for:
1.Chain wear, if chain diameter has reduced by 33% it is ready for replacement but not not likely to break imminently.
2. Check shackles for wear and tightness and that it is correctly moused. 33% rule applies. Mousing is especially important with new shackles which have been known to come undone.
3. Check swivels for wear, there shouldn’t be excess side to side movement. 33% rule applies.
4. Buoys should have a top plate and be free of tears or gashes. There should be no more than two other shackles attached to the main top shackle assuming two mooring lines. Buoys are rated with a maximum chain weight but the full weight of the chain is not always carried by the buoy unless conditions are poor. Do not use an excessive length of chain.

Repair of moorings with the tide in.

The simplest task is to replace an entire top unit, that is swivel upwards,with another that has been pre-made ashore. With lubricant it is sometimes possible to undo the shackle below the swivel, by putting the head of the shackle pin into the vice and using a crow bar to rotate the D.
If it is too tight to come undone then cut the lower riser at an unworn link below the swivel.
Most important -before cutting make sure the lower riser is attached to raft, usually the vice, with the hook as a secondary attachment and when your happy that the riser will not disappear into the depth, start cutting.

I’ve seen various figures given for the minimum length of riser in relation to the maximum water depth. I work on the basis of 3x the max depth of water giving a reasonable compromise between durabilty in the system during storms, swinging room and chain weight capacity of the mooring buoy. Over the years I’ve noted that some moorings have a lot more chain than this. If this is the case it may be possible to cut out worn chain without going below the minimum length of riser. The chain tends to wear more the the closer to the surface.

Removing portions of chain below the swivel is potentially more hazardous, if the chain becomes tight during the process it will start to sink the raft. I would recommend working on the lower riser at or after high tide unless the lower riser is excessively long and the sound section that is to remain, is longer than the depth of water expected. About a metre of chain above the surface is needed to secure for cutting.

Sinkers/ Mooring types
We appear to have three types;
1. Heavy concrete weight buried upto 1m depth with very heavy ground chain included in the concrete with a tail that reaches above the surface of the sea bed. I refer to this as the ground chain. The riser is attached to top of ground chain above ground level. The riser is divided by a swivel. The length of the lower riser should be a little greater than the maximum depth of water (2-3 m depending on position). This allows for easy replacement of the upper portion of the chain including swivel on any state of tide without risk of the raft being forced down.

2. As above but with no heavy ground chain tail, there will be half a link emerging from the sinker, perhaps with a single link attached which is well below the surface. The lower riser chain is attached to the sinker well below the sea bed. (Some would call this the ground chain as much of it is below or on the ground in all but heavy conditions.)
I consider this an inferior arrangement to type 1.

3. Least common are a pair of anchors or weights with heavy ground chain between the anchors with the riser attached to the middle. I would expect there is some movement on the ground chain to enable it to be pulled up to ground level with the raft but I’ve yet to come across this type.

Sinkers laid since 2012, currently numbers N1- N6 are type 1. Some older moorings may also be like this but are more likely type 2. Type 3 are most likely encountered in the vicinity of the winkle path.

Repair of moorings with the tide out.

This is necessary to completely replace the lower riser chain.

Recommended additional equipment; Quantity of water or storage for sea water, scrubbing brush, sacrificial length of rope. Spades.

Replacing the lower riser with a type 1 sinker is straightforward. Arrive at the mooring late on the tide and position the buoy as above. The buoy is hauled aboard and the chain then pulled up until tight.
As the raft dries out try and keep the chain central. If the sinker is type 1 it should be obvious by the presence of a shackle connecting the heavier ground chain to the lower riser. It is more pleasant to work on if this can be cleaned up.
If the shackle is at surface level it may be possible to cut it off without digging, however placing the hook below the shackle may cause it to jam so it is better to use a rope between the hook and link of chain below the shackle which can be cut or unthreaded after the new riser is attached.
Caution in needed as the ground chain my start to sink if unsupported.

If the chain below the shackle at ground level is the same or similar to the chain above then it is most likely that you have a type 2 mooring. There will be a swivel further down attaching the below surface chain it to a heavy link at the sinker. Someone will have put in the surface level shackle on a previous repair.
If you wish to check further down there is no alternative to digging. In this case the current raft makes things difficult due to limited space to work and place spoil. First consider the state of the chain you can see. If it appears to be in good condition then the likelihood is that all of it will be good.
If the chain is worn the better option may be to abandon that mooring and start afresh with a new sinker.

What to do when the task is completed.
Completing the work when dried out doesn’t take long if no digging is involved. It is necessary to have an idea of what to do when finished.
There are three options.

1. Wait for the tide.

2.Do the work with your boat on the mooring. This makes things more complicated but has the advantage of having a safe and comfortable retreat. I’ve never done this but I expect the easiest way is to have crew on the boat, who leaves the mooring whilst the raft moors to it, then the boat moors to the raft. The knack would be to have the boat not drying out a long way from the dried position of the raft which needs to be directly above the sinker.

3. Come ashore and collect the raft on the next tide.
This is hard work and potentially dangerous, with the risk of becoming stranded and exhausted, especially for more distant moorings.
Do not attempt unless confident that is within your physical ability and you have equipment to assist. Very few moorings are easy to access without safety equipment.

Options;
A light dinghy can be used and pushed ashore.
Two orange stretchers. Stand on one and push the other one ahead, then transfer. Repeat until ashore.
Members have built various contraptions which all involve spreading weight across a large surface with varying degrees of success.
Mud plugger boots work reasonably well. They are possibly the cleanest method and don’t take up much room, but they seem awkward to attach in the first place.
The quickest way to cross mud is to use a 3’ surfing body board ideally a good quality one with hard base. Kneel on the board with one knee, use the other leg to push across the mud. The board will skim across the surface at speed. Swap legs when tired which doesn’t take long. The dirtiest method and difficult to carry any equipment. Extreme sport.

With all methods keep to smooth mud if possible, although walking along the creek bottoms is often possible without aid.

This report does not cover the digging in of new sinkers. The current raft has been used to dig in recent sinkers but it is not ideal. Further guidance to follow when a new mooring raft is available.

Graham L. Mooring master. March 2022.