Laying a Swinging Mooring

Many cruising sailors cannot afford, or do not wish to indulge in 'getting the boatyard in' to lay or service their swinging mooring.Following TheMainSail's basic guidelines below, it can be a surprisingly cheap and straightforward task, providing you don't mind a bit of mud wrestling and weight lifting. The real satisfaction comes when you can sleep easily in your bed as the equinoxial gales come roaring through the anchorage and the halliards start rattling, safe in the knowledge that every shackle holding your pride and joy to the seabed has been selected, seized and peened by your own fair hand.

Basic principles

There are two types of swinging mooring; drying and deepwater. The basic principles such as weight and length of chain and orientation remain the same whether you intend your boat to touch the bottom or not. The only difference is in the type of anchors used, and this is due to the fact that in the drying scenario you can carefully dig your anchors in at low water, and can therefore use something cheaper and less 'anchor shaped' than you would be able to get away with in the case of a deep water mooring, where you just drop them and hope that they dig in due to their design. Using something less anchor shaped and digging it well in by sweat and spade is often desirable with a drying mooring due to the worrying dimension that the natural seabed scouring action can lead an anchor to become exposed, potentially endangering the hull if the boat dries out onto a fluke of her down tide anchor.

The business end of most moorings consists of two anchors, laid along the main axis of tidal flow, held together by a ground chain of substantial weight. A riser chain, leading up to the mooring and buoy via a hefty swivel is shackled at the centre of the ground chain.

Recommended specifications:

All recommendations are intended for average displacement monohulls under 35 feet. For heavy displacement boats or multihulls add 20% to sizes. For boats over 35 feet, seek professional advice.

Anchors
For a wet mooring: 2 to 3 times the weight of your main bower anchor, and of the same locally apropriate type For a drying mooring: As above, or seek local knowledge for a cheaper home made alternative
Ground chain
4-5 times the length of the boat. 1/2 inch chain or heavier
Riser
Lighter weight than ground chain. Distance from bottom swivel to buoy should be 2-3 times the depth at HW springs. Make sure you have enough swinging room
Shackles
Galvanised are fine. Go for the largest ones that will fit through your chains. Peen and seize all of them for peace of mind Swivel Galvanised are a false economy, half the price of stainless steel but last quarter of the time. Go for stainless.

Laying the mooring

The hardest job to contend with is normally getting all this heavy tackle out to the mooring spot. Local knowledge is the best thing to go by on this. It may be that you have a drying mooring on hard sand and the use of a club tractor to get it all out there at low water, but you can usually be sure that any problems you encounter will have been surmounted by countless boat owners in your anchorage in the past.

Many sheltered mooring sites in the British Isles will have muddy holding, in which case it's usually best to construct the mooring ashore then get it out to the area it is needed by boat. A big tender is usually man enough for the job for smaller moorings, but don't use anything too shiny and new as you're going to be allowing heavy chains to run out over the gunwhales. A battered old diesel workboat or trawler is the best. Some clubs use a moorings barge or pontoon which is generally a roughly square floating platform with a hole in the middle with a winch above. This prevents damage to any proper boats as it is simply towed into the correct places, and all the dirty business takes place aboard the barge. The winch is also invaluable for retrieving moorings once laid.

If you have a specific spot to lay the mooring, perhaps a GPS position or fix supplied by a harbour authority, you will have already made a separate dinghy trip out with a GPS and marked the spot with a weight and some light line with a small bottle or fender at the end of it.

Give a little thought to the order in which you load the boat or barge, putting buoys and riser in first, followed by carefully flaked ground chain and finally anchors. You obviously need to load the boat up in the reverse to the order in which you want it to disgorge its contents. One useful tip to make the anchors (always the most awkward objects) more managable, is to suspend them outside the boat from the gunwhales on some thin old rope that can be chopped through at the opportune moment.

If it's a drying mooring you're laying, simply deposit the whole lot in the area you want it, ideally by towing the mooring barge/ boat with another much heavier vessel (such as a sailing cruiser), dropping the up tide anchor first, followed by the down tide one, as far apart and as close to the desired orientation you can get them. This limits the amount of shifting of anchors and ground chain you will have to do.

Return to the mooring at low water and dig some holes, at least 18 inches deep, ideally two feet, next to the anchors, then simply roll the anchors into the holes and fill them in as best you can. It's also worth digging the whole length of the ground chain under too. This might need to be done in a series of tides.

What you use as anchors for a drying mooring definitely calls for local knowledge. In areas such as the Dee Estuary in NW England locals get away with a two foot square ¾ inch steel plate with a hoop bolted through the middle. As long as it's orientated correctly so the pull on the chain tries to dig it deeper in this works fine, as the soft mud around the flat plate allows a vacuum to form making it stick many times harder than its weight would suggest. In other areas, locals swear by old lorry wheels (always remove the tyre) or plastic oil drums filled with concrete. Whatever you go for, always assume that on a drying mooring the boat will try to sit down on her anchors at some point, so avoid anything that could cause hull damage and dig them deep.

A deep water mooring is generally laid after low water at the start of the flood tide. Attach a long loop, long enough to reach the surface from the seabed to the tripping eye of the anchor, which will be the down tide one. This needs to be strong line, so use the thickest stuff that will go through the tripping eye.

Drop the uptide anchor first, then tow the mooring boat down tide, allowing the ground chain to pay out. As soon as all of the ground chain is paid out, let the downtide anchor go, and lower it with the long loop line attached to its tripping eye. When you get to the end of this long loop, make it fast and give the throttle on the towing boat a blast to dig the up tide anchor in, once you feel it bite hard, let the long loop go, allowing the down tide anchor to drop to the seabed.

What you're trying to achieve here is the two anchors as far apart as possible on the seabed, and hence a fairly straight ground chain in between them.

Leave this loop attached to the anchor for now with a fender on the end, you will find it invaluable if the next part of the operation fails and you need to pull the whole lot up again to re- lay it.

Next, pick up the mooring itself, from the main mooring buoy at the end of the riser chain and tow it hard in the opposite direction to dig the down tide anchor in. Because you lowered the down tide anchor from its tripping eye, it should, in theory, have been deposited facing the right way on the seabed, so should dig in the moment you start towing it up tide. If it doesn't, you still have the tripping line there to pick up again and re-drop the down tide anchor.

When you're happy with the holding (Try towing the mooring in both directions) you can retrieve the long loop from the down tide anchor, by simply pulling it through.

Maintenance and inspection

Chances are, you will have to check your mooring on an annual basis for insurance purposes, although this would make sense anyway for any exposed mooring. Any mooring, no matter how sheltered should be inspected every two years as a minimum. Moorings almost never fail due to the chains themselves, the weak points are always the shackles and swivel so use the largest ones that will fit through the chain. As galvanised shackles are so cheap, whenever you go to the trouble of lifting your mooring, you should change all these as a matter of course.

The ground chain, being thick and usually submerged in mud, will rust very slowly, but the thinner riser, in the moving oxygenated water above will rust away very quickly. Some clubs advocate changing the riser every season. It's certainly worth inspecting every year, and when you do this, look at each link, carefully turning each one to check how much meat there is on the wear areas at the hidden inside ends of the links. If any link has an area that has been reduced to less than two thirds its thickness when new, it's ready for the bin.

Some owners like to try to protect their deck furniture by using a rope bridle on the riser. This is not recommended, as rope, even thick rope, chafes through too quickly. A loop made in chain, with a shackle makes more sense, and you can protect your deck and bow roller with a lenth of flexible pipe if necessary.

Tightening the shackle

Bending the wire

Twisting the wire ends

Wiring and peening a shackle

This really is the core skill you will want to get right for laying your own mooring, after all it's the shackles that hold the whole thing together.

Firstly tighten the shackle as much as you can by hand. You'll need some mole grips or a vice to hold it in and some pliers or an adjustable spanner to crank it up tight.

Then turn it over and hammer the (now hopefully slightly protruding) threads of the shackle pin over at the edges. Then take from 9 to 12 inches of monel seizing wire, bend the wire in half and pass it doubled through the hole in the shackle pin.

Twist the wire ends clockwise, pass one of the ends through the shackle and then twist both ends together. Finish with pliers, making sure the sharp ends of the wire are tucked away, especially if they are likely to come into contact with inflatable buoys or soft fingers.

	Jake Frith

Jake has written a number of articles for titles such as Sailing Today and ibinews.com, and is currently Editor of the RYA website. He also has a Masters in Online Journalism. Obsessed with anything that sails, from experimental windsurfers to heavy cruising yachts, Jake once sailed a £2000 Hurley 22 single handed round Britain and double handed across the Bay of Biscay. Not known for scrupulous solo watch keeping, he has run into both a supertanker and the Great Orme whilst asleep. Still a great believer in making adventurous passages in inappropriately small craft, Jake recently made the first (unsuccessful) attempt at rowing round the Isle of Wight in a single scull. He currently owns, cruises and races a Westerly GK 24, based in Southampton. Email: jakefr@southamptonrowing.org