Deep Water Anchoring

If your headed to Indonesia then this post should be of interest. 

We rarely anchored in deep water before we went cruising full time and headed off to distant shores. When we cruised the East Coast we thought ten metres was deep water and tried to avoid anchoring in any thing much deeper than five or six metres. There was a couple of times we did anchor in ten metres but it wasn't often. We would easily and often anchor in five, this depth would allow the tide to run out two metres and still leave us with a meter under the keel at low tide.

Not how you want to begin the day. 

When we were getting ready to head off to SE Asia we were bombarded by different views on how to anchor in the deeper water. One couple that had done several trips into Asia would give out advice to anyone who would listen. After talking with them briefly about anchoring we started to doubt our preparation, we began to think we didn’t have enough rode or for that matter how could we actually carry enough. We really don't know how this couple anchored exactly, what we do know is they carried an extremely long length of chain.  We later found out this chain was smaller in diameter than our own, and they had an old generation anchor on the end of it. We can only assume they carried extra length of smaller chain and tried to maintain the scope mantra often repeated in online forums, training courses and yacht club bars.

Fortunately we ran into other couples who had done several trips in SE Asia and they explained that one hundred metres of chain is more than enough and we shouldn’t worry at all. They went on to explain that in the deeper water we can start to rethink the ratios we are consistently told work and start to properly use the catenary effect of the chain. Anchoring in deeper water really calls for a different approach to the rode, depth, scope ratio’s we have all heard so much about. One of the couples had anchored in thirty metres regularly when they explored the eastern islands of the Indonesian archipelago.

For us anchoring in shallower water had been the norm, we had been using snubbers for some time and had worked out an easy to use system. We had been in some serious storms at anchor and could see the chain pulled taught while the snubber absorbed the energy generated by the snatch loads this reduced the chance of damaging the vessel, breaking the chain or dislodging the anchor. We saw time and time again that when anchoring in shallower water it didn’t take much of a storm or increase in wind strength to pull the anchor chain straight and taught. This is mainly due to the lack of depth not allowing enough length of chain to hang into deep water to develop and maintain the required curve for the catenary effect absorbing the shock loads on the anchor.

To anchor in deeper water was not going to be as tricky as we first thought. However it is a whole anchoring system not just the anchor and chain.

Now I have said that, the first thing I am going to discuss is the Anchors.

Anchors

Size does matter! and the bigger the anchor you can fit on the bow of your vessel the better. Look at the selection chart for the anchor you have and compare it to the other manufactures charts. You are likely to find most anchor manufactures will recommend anchors that are too light for the size of the vessel. I am lead to believe this is a marketing ploy to stay competitive with other manufactures who also under size the recommended anchors. If a recommended size anchor is cheaper for a given size of vessel, they are more than likely to sell more anchors, and the way I think it works is when boat builders fit out new yachts, they are looking to reduce costs. They will purchase the size recommended by the anchor manufacturer, not the size recommended by the cruising community, who know from experience the recommended anchors are too small for anything other than a picnic stop for lunch on a calm day.

I could go on and explain the benefits of the new generation anchors, giving a break down of brands and types but I won’t as I have found it causes to much friction, people have a habit of defending even their worst purchase choices. 

What I do know from experience is, the new generation anchors work better. We should also know from extensive testing by yachting magazines, private individuals and even company sponsored anchor testing the new generation anchors out perform the older generation anchors on just about all points of the tests. Yes I know every now or then one of the old generation anchors does come up and surprises all the testers, however it's rarely consistently repeated. 

So the best thing to say is when purchasing an anchor, get one of the new generation anchors. Look carefully at the sizing guides to get an average weight for an anchor to suit your vessel. Discard any guides that recommend remarkably lightweight anchors through the range then go up 2 sizes and you should have an anchor that allows you to stay put when the wind comes up in the middle of the night. Another thing to look for in the test data is a common thread, if an anchors holding power is low → medium more times than it is high (even though it's advertised as "Lloyd's listed as High Holding")I would give it a miss. 

Reality check: High holding is ok however in the cold of night an anchor with super high holding rating certainly helps soothe the nerves when the wind comes up.

Snubber’s

We have found a snubber is a vital component of the anchoring system if you use all chain rode. A snubber is a length of strong but stretchy rope (nylon) anything from 5 to 15 meters long, one end attaches to the anchor chain as the last of the chain is deployed and the other end tied round the bow mooring cleat. We have seen all manor of snubber’s in our travels and unfortunately a lot would not do what they are supposed to do.

Snubber's are best made of nylon because it stretches and is strong, it has good UV protection, will work wet, is easy on the hands when handling and is easily spliced. To have an idea how big a diameter you need requires experimentation. Start by looking at what wind strength your anchor chain starts to become straight, (every vessel is different) its at this wind speed you want the snubber to be adsorbing the energy from the vessel movements. On our vessel we use a long snubber that is two millimetres smaller than the recommended anchor rope diameter. There is no magic bullet with one size fits all when it comes to snubber’s, there are so many variables and a decision must be arrived at for the individual vessel. Things that will ultimately decide the length and diameter will include vessel windage, displacement, chain size (weight) and anchoring points. I recently read in an online forum where there are some who use mooring micro snubber’s and mooring lines, unfortunately for them nothing good can come from these setups. Mooring lines and equipment isn't made for anchoring and has the potential to be disastrous.

The amount of stretch is directly proportional to length.

• A 8m long snubber can stretch twice as much as a 4m long snubber.

Or inversely proportional to the square of the diameter.

• A 10mm diameter snubber can stretch twice as much as a 14mm diameter snubber.

As an example a 12mm diameter nylon snubber when new (breaking strain 3000kg) has about the same breaking strength as 8mm Grade L chain (3272kg breaking strain)

Testing a new snubber @30 Knots in shallow anchorage the chain has straightened out

A smaller diameter nylon snubber is strong enough to add the required stretch in the system, however a large diameter snubber or a snubber made of the wrong material totally defeats its intended purpose. I have heard catamaran owners happily telling others they have an oversized or ruggedly constructed bridle for anchoring. While this sounds great in theory, in practice this will only add to the grief of having problems when anchoring. Without incorporating a springer into the bridle there will certainly not be enough energy absorbed due to the boat moving when the weather comes up.  If the ruggedly constructed bridle has limited stretch the only thing that's going to happen is the anchor will be slowly dislodged one little shock load at a time. 

We attach our snubber to our anchor chain with a Dyneema loop, makes it easy quick and light weight. The best thing is its easy to go through the bow roller and doesn't fall off when you need it most as the boat starts to move about. 

Use better solid thimbles in the snubber (top), the standard thimbles can distort badly and fail under high storm loads (as we found out)

Snubber to chain connection, only takes as long to attach as doing up a button and doesn't fall off, and can be made onboard if you have the raw materials, Dyneema cord and 5 minutes of time. 

Galvanised Anchor Chain

Selecting the right type of chain can be very confusing due to different grading systems. There are a variety of link sizes and the best thing to do is take your chain capstan with you when you do make the final decision on the chain supplier. Make sure the chain is a perfect fit into the capstan and does not bind when the chain rotated through it.

Is it better to have a long length of high strength light chain or a shorter or same length of lower strength heavy chain? Both have energy absorption, so there is not much point in using high strength chain as it corrodes quicker and can actually be brittle, which can cause handling problems. When its all said and done it is certainly best to use a long length of heavy chain!

We get by with 110m of chain, and I don't remember there is any time we thought we needed any more. We do however keep a 100m coil of nylon and 30m of chain as back up in the locker, but have only used some of the rope when it was time to cut off several metres for various jobs.

Anchor Chain Storage

In a lot of anchorages the bottom is sand, broken coral, mud (some times putrid) and or a deep layer of the ever present plastic bag so have a pressure saltwater wash down hose, you may have real problems if you rely on a bucket on a string. We know of one cruiser who ended up with several kilograms of putrid mud in the anchor locker due to blocked drains that required him to deploy all his chain, clear the drains while washing out the mud. What we found is that plastic bags or pieces come up in the mud from the chain or anchor and it doesn't take much for a piece to block the locker drain.

Anchoring In Deep Water

You can pretty much throw out the old scope ratios we have all read about in the sacred texts that were written by the ancient mariners. So for example if we were to go with the standard 5:1 that is used in shallower water. Enough chain to obtain the 5:1 chain to depth ratio in 25 metres of water is going to require 125 metres of chain, and if sticking to the convention even more if the weather is coming up.

So now on to something we used successfully. This will really only work if you can anchor successfully in shallower water. If your vessel usually skates off when the breeze comes up then this won't be a fix, and you are likely to still skate off on the breeze. Every one we talked to who had successfully used this technique had a new generation anchor, but that's not to say it won't work with older styles of anchor. Some who were unsuccessful did also have trouble anchoring in shallower water, and with out being to specific it was usually a combination of problems. These included under sized chain, undersized or old generation anchor or both, poor use of snubber or not using a snubber at all. 

What technique worked for us: Lay out 20 metres of chain and then lay out a length double the depth and don’t forget to use a good elastic nylon springer (minimum of 6 metres long), if its a bit windy or you require a little more security add another 10 - 20 metres of chain. So if anchoring in 20 metres lay out 60-80 metres of chain. If your really worried, let out all your anchor chain from the locker. While this twenty metres and a length double the depth doesn't sound like enough, due to several factors you will find it should be. Keep in mind if your securing the snubber to the mooring cleat at deck level of the bow roller then allow for this, deploy extra chain double the distance from water to the bow roller.

Water Depth Catenary chart

How does it work: In the deeper water the chain is allowed to hang into the depths. There is a lot more weight of chain suspended in water and now the catenary effect is very effective at absorbing the energy created when the boat is moving. Where as in the shallower water it doesn't take much additional wind to make the chain straighten out. When the chain straightens out there is very limited (or no) energy absorption, and this allows any vessel movement to be transferred directly to the anchor and the vessels cleats. This additional load from the increased wind strength and movement of the vessel due to wave movement creates high shock loads which can quickly dislodge the anchor or damage the boat.

You can have the best technique, and be anchored nice and snug in deep water, however if the wind turns and the fetch allows a large swell to roll into the anchorage all this work can come undone. We had this happen on occasions during the monsoon transition months, or a Sumatra winds coming in at O'Dark Thirty, always have a plan B mapped out.

We also anchored in very deep water where it went from the shore to 40 metres in three to four boat lengths, while this sounds crazy we would set up a stern line to shore and then drop the anchor out in 50 plus metres, then back down while bringing in the stern line. We found that even with a steep sloping bottom the anchor would dig in and wouldn't budge. Having the stern line stopped the boat swinging and pulling the anchor out into the deeper water. Even still it did give us an uneasy feeling looking out the back and feeling like we could just step out onto the shore.

Below is an excerpt from Rocna Anchors site, and while I am not advertising them, I believe this to be a good description of the definition of old generation anchors.

Old generation anchors include most types and designs dating before the Bügel (1986) and Delta (1990). Because the Bügel uses what we consider to be some new generation design characteristics whereas the Delta is first and foremost a plow, these two types define a bit of an overlap between the 'old' and 'new' generations which marks the transition from old to new on the timeline.

Below is the remains of our snubber after being caught on a lee shore with three nasty storm fronts coming in unannounced at O'Dark Thirty with the South China Sea as fetch. While we weren't anchored in deep water, I have put it in for reference, and why it's important to use high spec gear in the anchor system, and an example of how a simple Dyneema loop can hold fast.  

This is how well the Dyneema Loop holds on, this thimble was at the anchor chain end and held on until the snubber became so over worked it melted and then parted. 

What remains of a well used snubber, while its not easy to see the snubber worked so hard during the storm the core is fused together from friction. Interesting evenings entertainment, three storm fronts came in at O'Dark Thirty and had us pinned on a lee shore until we were able to pull the anchor up and get out of there. The snubber parting happened shortly before getting underway.

Back end shot of the distorted thimble. We now source heavier duty thimbles for use in our anchoring system. 

I am not promoting these anchors and I don't want to upset people however here is a link to Yachting Monthly with a short list of New Generation Anchors, and there isn't a Plow or Delter to be seen. I have worked in the marine industry for over 20 years and lived aboard for 13 years and have sailed most of my life.  I've had my fair share of old generation anchors. One such incident sticks in my mind when anchored in a bay with good holding, we woke when the wind came up, I was searching for my trousers while Deb was looking out the portlight saying all the boats in the anchorage are all leaving at once.  It took a moment for what she said to make sence, they weren't leaving we were going backward through the anchored boats at speed, quick start the engine!!!.  

Anchoring are We Getting it Right

 About seventy vessels more or less in the anchorage a big storm and a muddy bottom. A night of mayhem ending with bruised and battered boats. In the cruising community there are still things to learn about anchoring. I can safely say we are not experts and we did increase our knowledge from what we learnt that night.   

The Sail Indonesia rally fleets joined others who had sailed and motored in from different parts of Indonesia, Singapore and Malaysia to be part of the marine festival celebrations. We were all anchored in the Tanjung Pinang anchorage and by our calculations we estimated there was about seventy vessels more or less in the anchorage on the final evening. The vessels ranged in size from something that looked like a floating block of flats to small sixteen foot cabin cruisers. This is a well-protected anchorage for anything other than weather coming in from the west. So after the day’s hectic social events we were enjoying a drink and winding down prior to heading back out to the boat. At around midnight we noticed the lightning on the horizon to the west getting closer and knew from recent experiences a storm front was on the way. Oh great that’s all we needed was the cry as drinks were left unfinished. There was a scramble to the tender dock and before the last boat had left the dock the waves were already quite choppy and it was hard to board our tenders. We were lucky enough to get back to the boat relatively dry and tied the tender up tight off the stern in case we needed to do any manoeuvring later. 

Stormfront on the way out of the West.

                                                                            

VHF crackled warning others they were not holding

Then it was on, it started with an icy cold breeze and large claps of thunder as nature unleashed her fury, the heavens opened up, rain poured down as the wind rose to a crescendo and the rigging whistled as the wind strength exceeded forty knots. As the storm progressed so did the wave height, it wasn’t long before there was surf rolling through the anchorage. Boats rose on the wave peaks straining on their anchor chains, the wave would pass and the boats surfed slightly down the back of the wave before the next wave lifted their nose pushing them back to strain on their anchor chains again. The VHF crackled with different boats communicating with neighbour's or warning others they were not holding, then there were the boats trying to untangle anchor chains and what to do next.

The storm is increasing looking west over to the ferry terminal,

Seventy five percent of the boats in the anchorage dragged.

For the next three hours about seventy five percent of the boats in the anchorage dragged. Some of the dragging vessels smashed into others and took out or dislodged the anchors of vessels that were not moving so as you can imagine it was mayhem on the water. We had several vessels anchored around us and it was nerve wracking trying to raise the sleeping occupants as their vessels were on collision course with us or other vessels. I remember one comment a friend told us when they rose from bed disorientated and looked out the porthole of their vessel as it was dragging backwards through the anchorage. She commented to her husband that all the boats are hastily leaving the anchorage dear, so please get up quick and have a look. A look out the port hole was all he needed before urgently crying get up on deck they aren’t leaving we are going backwards, let’s start the engine or words to that effect!

Just about past waves and wind have died down

There was a lot of damage to vessels

In the morning once things had settled down we went out and had a drive around the anchorage in the tender. We wanted to see how our friends went during the storm and did they require any more assistance. The rally fleet participants were very concerned because there was a lot of damage to vessels that night. One local vessel sunk not far from us and one of the participants on our rally had their vessel end up perched on the stairs of the local ferry jetty. It’s funny but not the ha ha type of funny, but the peculiar funny, it’s how you notice things in a different light the morning after a night of chaos. The one thing we did notice in the tender ride around the anchorage was the lack of snubbers or the incorrect use of snubbers on a large percentage of the vessels in the anchorage. However this wasn’t the first time we have notice it, we have seen it time and time again when we are in Moreton Bay with boats going every which way (usually with the wind) during a storm or a bit of a blow.

The local fishing village, several boat sunk including a large tug tied up at one of the docks.

While the owners were on shore their vessel was re - anchored

Once you get a group of yachties together for a couple of months, if you take a little notice patterns start to emerge. Throughout the rally one vessel always moved when the wind came up, and the morning before the big storm while the owners were on shore their vessel was re - anchored after it was found moving backward through the anchorage again about to collect another vessel. The person who re-anchored it was another catamaran owner and noticed their bridle wasn’t set right nor was there enough chain out for the conditions. So he anchored the vessel as he would his own cat, and possibly for the first time, during a storm this vessel didn’t move. The owner was so impressed he actually asked for hints and tips, because in his words “this is the first time we didn’t drag in a storm” he didn’t think it was possible not to move. No wonder he was always a nervous wreck as soon as the wind rose above ten knots.

Tests are conducted in a controlled environment 

Over the years I think we have all read the results of the last round of anchor tests. I wouldn’t be alone in saying that I actually bought a magazine to read the test results. Then on the strength of these tests some of us have then gone out and paid large sums of money to get the anchor that turned in the best test results on the day. While it’s great to buy the anchor that comes up as the best with exceptional holding, it won’t however be the best unless it’s used as part of a whole anchoring system. As you know these tests are conducted in a controlled environment and usually but not always only measure the holding or drag exerted on a load cell. This doesn’t test a whole unique anchoring system. The whole anchoring system is rarely tested and really unless it’s a high volume production vessel with identical systems, more than likely the anchoring system you have on your vessel will be unique.

You may find it doesn’t hold as tested

So if you buy the top rated anchor, tie on a length of rope and drop it off the front of your vessel, you may find it doesn’t hold as tested. So you start cursing the tester and his report. However, if the anchor is part of a whole system built up of several carefully selected components, you may well find the steel vessel, because they are heavier than any other aren’t they? To which the said anchor is attached doesn’t budge even through a full blown gale in an ebbing spring tide in a muddy river during a flood. So one of the components for an anchoring system is a snubber, don’t let the name fool you it’s a very important component and does a great deal of work if set up correctly. Dock line snubbers are not the same as an anchor snubber so please don’t confuse the two.

The wrong place for a mooring springer, in reality this isn't going to do much and with loss of tension the chain hook will fall off, there is nothing holding it on. 

Points for having a snubber

1. The snubber bridle removes the wrenching jerking motion on the anchor chain and in doing so softens the yanking motion on the anchor giving it the greatest chance of staying put in the sea bed

2. The snubber bridal takes the anchor chain strain off the windlass gypsy reducing the stress on the windlass installation and wrenching on the bow roller

3. Allows the load to be taken by the cleats or other method designed for high loads

4. Noise is greatly reduced down below because the load is transferred to the cleats via the snubber

5. On the average size cruising vessel the catenary effect from the chain does not provide any significant shock absorption once wind speed negates the effect

6. Helps protect the hull when the vessel moves forward over the rode, in most cases only the snubber rubs on the hull not the chain saving the top sides paint

I would say most of us have heard it suggested that when using all chain rode the catenary effect of the chain sagging because of its weight will provide sufficient shock absorption. While this might be true for larger ships with anchor chain links the size of cars and anchor in deep water, the catenary effect from the chain on the average size cruising vessel anchoring in shallower water will not provide any significant shock absorption, just look at the chain shape in a breeze > 25 knots you see that the catenary effect is no longer a factor because the chain is pulled tight in a straight line. So simply put, the use of a snubber ensures that your anchor has the highest chance of staying put where you placed it. 

I will add a disclaimer here, this lack of catenary effect is mostly due to the depth we as cruising yachts like to anchor in, the shallower the depth the less likely catenary it is going to come into effect. Deeper water will certainly help due to the weight of chain hanging in a loop, gravity will be doing its work. The shallower the vessel anchors the less likely catenary effect will come into play. So with this lack of catenary effect the shock loads are certainly increased on the anchor and this is why a snubber is so important in shallower anchorages. A springer is still important in deep anchorages but comes into it own in shallow(er) anchorages. Also keep in mind chain weight, high tensile chain may save weight but also lessens the catenary effect, is more brittle and is likely to snap rather than elongate. 

Just on 25 Knots chain is pulled straight beyond the snubber Dyneema loop in use

Naively the owners drop the pawl onto the gypsy / capstan 

We have noticed that a lot of people don’t realize that a snubber must have good elasticity, because there are so many in use that don’t. Take a quick look around the anchorage next time the wind pipes up. You will more than likely see one or two vessels with no snubber and the chain is just held in place by the winch and naively the owners drop the pawl onto the gypsy / capstan that was meant for use only when operating the winch by hand. In a good blow the excess force on the pawl has been known to break the pawl bolt clear out of the winch housing casting letting the chain run free. I know the instruction manual with my winch refers to this and it states that this pawl should never be used to lock the chain gypsy rotation as an anchoring method.

Look around some more and you will see that there are vessels straining at the anchor (anchor chain in a straight line from snubber to anchor) and the small chain loop behind the attached snubber hook does not change. There is no shock reduction other than the load is removed from the anchor winch. This lack of elasticity is a problem that may be traced back to the length of the snubber, some are no more than 400-600 millimeters long while others are of the wrong rope type or the rope is too large a diameter to allow any stretch. 

Heavy rope with a small loop wont do much good
 Hull damage due to chain scraping top
sides during wind over tide

Unfortunately, the majority of discount chandleries sell silver rope as an anchor rode because it’s cheap and then it starts to become the rope of choice for all things anchor on some vessels. This is a bad state of affairs, silver rope may be ok for the weekend power boat that is driven right on to the beach, but it is not the rope of choice for anchoring larger vessels in any weather.

Silver rope is furry when new and in most cases when its no longer furry it is getting too old and from my experience past its use by date 

We wanted a snubber system on our vessel that would work and was easy to use, as stated earlier it had to add sufficient elasticity to reduce shock loading on our all chain rode and remove the anchor chain load from the windless. Another requirement was to make sure it didn’t require additional consumables or an additional task other than removing the attachment during deployment or retrieval. We wanted the snubber to be long wearing, virtually maintenance free and we didn’t want any slipping on the chain. Furthermore, I didn’t want any dissimilar metal contact for example a stainless steel hook on a galvanized chain. Due to vessel design, I needed it to run over the bow roller when deploying and or retrieving the anchor chain with out causing damage to the roller cheeks.

Not a very good setup, this arrangement wont do much to help with holding, I am not 100% sure but it looks like a shackle holding the rope to the chain, could be difficult to remove in a hurry.  

Traditionally snubbers have been attached to the anchor chain with a variety of snap shackles, quick release hooks, steel chain hooks and purpose made chain attachment plates. All are proven to work, however some are better than others, but they can also have some downsides as we found out. Large snap shackles and quick release hooks can straighten out or become badly distorted if put under too much load. Exceeding the SWL (safe working load) if certified can lead to total failure or distortion of the hook. We have had the steel chain hooks wedge onto the chain after being anchored in a decent blow. The other pitfall with chain hooks is they can fall off the chain due to a multitude of reasons, for example, when you are running the chain out and loose tension, or the wind dies and the chain goes slack when it rests on the bottom, the tide turns or you experience wind over tide; there are tricks to minimize the hook falling off. We did use insulation tape to hold our hook on, but it is a constant problem and adds another task to do when deploying or retrieving the anchor and then you need to keep hold of the used tape so it doesn’t go over the side and become another piece of plastic in the sea. Friends purchased a fancy purpose built anchor chain hook and found that the plastic keeper to stop the chain from accidental disconnection would wear off or break when anchored in shallow water and the snubber ran along the bottom.

Snap shackles can straighten out in a blow

Another aggravation we have encountered is that most of the chain hooks will not run smoothly over the bow anchor rollers either when deploying or retrieving. Usually deploying isn’t as big a problem where you can hold and guide the hook and associated hardware up over the bow roller cheeks with the snubber, but this isn’t something that’s easy to do when retrieving because the hook is coming over the roller first. Really these little things are only acceptable in good weather, it’s an annoyance we accept, but when the weather is closing in and you don’t want to be here, the wind is picking up and the waves have started to become slightly bigger, that annoyance can become a real game changer. The bothersome hook arrangement can get caught or tangled or worst of all try and take the tips off your fingers when you try to untangle or unhook it on the pitching foredeck.

The chain is to tight and may tear the bow sprit off  if the wind comes up. The length of line for the springer is too short and not enough chain has been deployed

As far as I can see some hook up arrangements are a safety hazard. I have noticed people straining to reach out over or under the pulpit to either connect the snubber/bridle on to or remove it off the chain, this over extending isn’t doing anyone any good and could lead to strains or worse a person overboard if they over balance. Recently I witnessed a couple try for a good five minutes to get a hook attached to their anchor chain, they were basically fishing and trying to snag the chain in the hook as they hung over the front of their vessel. Thinking this was a one off event when I saw them on shore later that day I asked about the trouble and was told this was quite normal as their hook arrangement won’t fit through the bow roller.

Chain hooks will fall off easily or wedge on the chain after a blow and don't go through the bow roller easily. Shown here with the snubber rope removed. This was our setup and I was so glad to see it go, it was always when you needed it, that it had fallen off. I was always worried I would loose a finger getting it through the bow roller when hauling anchor in a pitching sea 

Soft shackle, connecting it is very similar to doing up a button

The way we achieved our requirements for easy deployment and retrieval was with a soft shackle or loop made of Spectra/Dyneema fibres. Loops made with the two popular brand named products have been made to replace many steel shackles and some other fittings above deck. So after talking with a friend who was making fibre loops from Dyneema for his new catamaran I saw that with a simple change we could use it to quickly attach and de-attach the snubber from our anchor chain. We removed the cumbersome chain hook and associated hardware that had made connecting the snubber a chore and went with a simple strong fibre loop. No snags any more coming or going over the bow roller so since then we have never looked back. Keeping in mind we anchor just about every day, we get two years use before I retire the one I am using, well that is unless I drop it over the side. I have only done it once and before I could get the boat hook it sank out of reach. As a guide, here is a table detailing breaking strain of nylon rope and high strength fibre rope.

Soft shackle connected to the chain. 

Attaching the Dyneema loop to the anchor chain is relatively straight forward. The loop is designed in such a way that the Dyneema rope eye closes around the base of the stopper knot under tension. The more tension on the loop the tighter the loop eye constricts around the base of the stopper knot. Connecting to the chain is done by feeding the rope eye portion of the loop into a chain link at the position you require the snubber to attach. The snubber eye is enclosed in the loop and the stopper knot is inserted into the Dyneema rope eye, then tug on the snubber to tighten the eye around the stopper knot and then deploy.

This table is the breaking strain not the safe working load limit which is a lot less.

Nylon                                Dyneema

10mm 2100kg                   6mm      4200kg

12mm 3000kg                   7mm      6000kg

14mm 4100kg                   8mm      6600kg

16mm 5300kg                   9mm      9000kg

20mm 6260kg                   10mm  10700kg

24mm 12035kg                 12mm  13000kg

How well does a Dyneema loop stay attached to the anchor chain? We have been caught in a couple of nasty storms during the season transitional period while sailing in Asia. This has meant we have been caught exposed to the full force of the wind, and large expanses of ocean as fetch. Most of the time we are able to get the anchor up and get around the corner or headland to hide or go with it until the storm has blown its self out. Unfortunately on a very memorable occasion we were caught in a bay with several obstacles that made our escape hazardous. We had to stay anchored longer than we would have liked with storm force wind and seas that became well developed (surf). The photos of the galvanized thimble I think display just how well the Dyneema loop can stay attached to the chain and thimble.

Fairly standard gal thimble, its easy to see the force the shackle was under during the storm

Another angle of the thimble distortion 

Another angle showing the compressed distortion from the soft shackle 

Below is a table I used as a starting point for putting together my snubber. One important rule is that the lines must be nylon to afford the required stretch. I have also found that it’s not the best to deploy the full length of the snubber until I am anchoring in deeper water (>7Metres) or I know a blow is coming my way. Like nylon anchor rode the snubber can suffer abrasion if it is deployed onto an abrasive bottom. As a rule I work out my water depth when anchoring and set the snubber to just be above the bottom at low tide. So as an example with a two metre draft and two metres under the keel plus two metres from the cleat to the water line I will deploy a snubber length of six metres. With a short snubber of six metres ten percent stretch will give you over half a metre (0.6M) in moderate winds and as the wind increases fifteen percent stretch would be just under a metre (0.9M). The nylon will usually part (break) at twenty eight to thirty five percent stretch depending on the brand. I have used nylon rope one size down from the charted size e.g. 13M boat 12mm snubber at full ten metre length when anchoring in soft mud. If used regularly (daily) the snubber should be replaced annually due to consistent stretch and UV degradation. Chafe protection will be necessary as the snubber will come into contact with the anchor chain regularly. A length of plastic tube approximately one metre long with a three millimetre cord used to adjust position should suffice.

A heavy duty thimble spliced into the new springer, compare with a standard gal thimble bottom, there are even better thimbles with the tail welded and loops around the line to keep the thimble in place if the eye is under tension and stretched. .

To make a snubber is relatively simple, get a length of good quality three core nylon to suit your vessel (see table below) and splice a thimble or have a thimble spliced into one end is all that is needed. If you want to use eight plait or climbing rope go ahead but it does take a little more work. However, while it does look good for the first month or so before it becomes camouflaged in the sea green if used regularly, make sure you purchase heavy duty thimbles, sorry to say you’re most likely not going to find these on the shelf of your local discount chandler. Head off to someone who sells rigging/lifting hardware, and for a few dollars more you will come away with rope thimbles that won’t collapse in a big blow.

Keep in mind that this table is a guide only, due to the various shapes and sizes of vessels. An older mono hull vessel where the decks are lower to the water line will have a lot less windage than some of the newer builds with voluminous interiors and high sides. The same is true with catamarans, the earlier builds were close to the water, and now the newer builds with palatial cabins below decks and lounge rooms above do offer a larger area to the wind.

Snubber                      Boat Length      Nylon Rope Diameter
Length in Metres        Feet  Metres       mm

6                                  25-30 7.5-9         10

8                                  30-39 9-12          12

8                                  39-44 12-13        14

10                                44-50 13-15        16

12                                50-60 15-18        18

Some people say that with the long snubber bridle the chain is lowered below the waterline so it affords better scope. I don’t believe this is true, just look at the snubber in use in 25 knots or more of breeze it can almost come clear of the water. For better scope you would need to lower the attachment point on the vessel. The reality is that the snubber connection to the chain should be well below the water, if it’s not your snubber is too short or it’s blowing really hard. I have found that at a minimum the chain/snubber connection should just be above the bottom at low tide except when anchored in soft mud deploy the full length snubber along with extra chain. Perhaps a lower snubber attachment point (cleat) to achieve better scope may work but it will be difficult to attach the snubber on a cleat near the water line from up on the deck of the vessel.

Just on 25 knots the anchor chain is in a straight line to the anchor. Springer line has got a fair amount of stretch at this point. 

In the season transitional storms mentioned earlier on, in one storm we lost two snubbers due to them becoming over worked. It’s hard to believe but the one snubber we were able to retrieve had the core melted, it had become so hot absorbing energy. On inspection I found it could not be unwound and had parted I believe due to heat. In hindsight, if I had let out more snubber length earlier in the storm the snubber would have been able to absorb the energy and would not have become over worked.

The remains of the snubber the strands can not be unwound due to being melted together in the core.

What else in your anchoring system? Chain is without doubt the rode of choice for cruising boats. It’s hard wearing and hard working. If the bottom is abrasive it won’t wear through a chain easily where a nylon anchor rod can be damaged in the course of an evening in the right or should that be the wrong conditions. Get good quality marked chain from reputable manufactures. Cheap chain with no identification marks as to type or manufacturer has no place in the chain locker. When you purchase chain always ask for the proof certificate, this is a little bit of insurance your chain has been tested. Because you have the certificate you now know that firstly you’re dealing with a tested to failure product and secondly you know some quality inspections have been carried out during the manufacturing process.

Another thing that is worth a mention is that it’s usually a better option to purchase a chain from a manufacturer. Not from a dealer (supposed chain manufacturing company) who sources the chain manufacture out to another company, usually somewhere in China not that that’s always a bad thing. During my work we got into all sorts of problems with a manufacturing company who after years of dealing with them, decided to outsource their chain manufacturing. From time to time the supposed chain manufacturing company would source a new manufacturer and twice during the changeover period there was serious problems with chain quality. The down side for us was that it was causing thousands of dollars loss through down time and equipment damage when some chains failed. We had to find a new supplier who would audit the manufacturer on a regular basis to improve the product quality. For those of you who find this to be a bit farfetched, I seem to recall something about an anchor manufacturer out sourcing and having the odd bit of trouble. 

So how much chain do you need is totally up to you really, having just completed a journey through SE Asia and anchoring in all sorts of conditions and bottoms and now ten metres is the new five. Depending on the boat and area of operation, I would say to start off with eighty metres but one hundred would be better. One of our friends has gone with eighty metres of chain and has fifty metres of nylon rope he attaches for the really deep anchorages. He doesn’t lay the rope on the bottom but deploys enough to keep it off the bottom at low tide, so he rarely goes anywhere because he can have eighty metres of chain on the bottom in deep anchorages. We are frequently anchoring in ten to fifteen metres and one evening we anchored in twenty eight, yes every last bit of our hundred and ten metres was out of the locker that night. 

Chain size? While not going over the top it’s better to have more weight on the bottom rather than less. So if you think a high strength chain of a smaller diameter sounds like a good idea it may be false economy because you may find you need to let out more length to get the weight on the bottom. This will then increase your swing room and may be the difference of anchoring in a tight anchorage at the end of the day or sitting outside in the weather. The other factor no one appears to talk about is that the higher the chain tensile strength the more brittle it becomes, this may not matter where anchoring is concerned but it’s worth knowing about.

The most important item in your system that will make it easy to find the end of your chain is an anchor. So, how will you make the right choice when it comes to selecting the anchor design that suits you? It’s not quite as easy as you may have first thought and your research options are certainly limited. If you take all the claims and endorsements seriously and at face value you would really have a problem making a choice.

The old tyre is not much of a springer, softer perhaps but not much good to keep you anchored in place. 

You can read the manufacturers claims all day long and I am sure most will excite you. But always keep in the back of your mind that they are trying to sell you a new anchor made by them, the best bet is to talk with other cruisers but take into account that its part of human nature to defend even our worst purchasing decisions. I would consider that it’s remarkable to talk to anyone who has never ever dragged, as with the manufactures you can’t take every ones comments at face value either. I remember a people’s behaviours quote my father would tell me about there being two types of sailors in Moreton Bay, he would say that there are those who have run up on a sand bar and then there are those who lie about it. However if you ask enough people you may see patterns emerge especially if you ask about other boats/persons anchor performance.

The other way to consider a new anchor purchase is to look at the independent testing results, these are most likely a reasonable bet, but you do need to realize almost everyone has a schema. You will also need to look at as many test results done by different people as you can. This should help find the anchors that perform well just about every time, lack lustre performance and hit miss results should be enough to eliminate poor performers. I remember seeing anchor tests over the years testing the same anchor and one will say that it works fantastic in mud the next review states this anchor doesn’t work very well in mud. The other hitch that I think confuses the issue is the same or slightly changed press release doing the rounds year after year with no new tests, it worked in tests years ago so don’t retest just keep retelling the same great results, and where and who by its earned accreditation.

I have seen supposed true endorsement of anchors or accessories on line and due to the over enthusiasm of the review and the known holes in the story, I feel that somewhere or somehow money or goods have conceivably changed hands. I have even read one review where an anchor was blamed for electrolysis on the vessel due to a fault in the anchor winch, but that was only one grievance amongst a long list of others. Funnily enough the vessel never ever dragged again once the new anchor was in place, which must have been a relief for the captain because it had moved every time they anchored with the previous anchor. Somehow I just don’t believe it, knowing the reputation of the anchor they put on.

Without doubt the new generation anchors worked the best during the storm in question, but that said one brand didn’t work as well as the manufacture's would like us to believe. If the anchor is based on an old design with a few changes then really do your homework, if they just turn in a satisfactory or good all-rounder during anchor tests then think again and look for exceptional holding because that’s what we all want at three in the morning on a hot and windy night. But the thing we all need to keep in the back of our mind is the fact that like the weather the holding is only as good as what you are experiencing right here, right now in this small patch of the ocean. But if our vessels are set up to help keep us anchored to this small patch of ocean floor we may all be able to sleep better.

With a new anchor purchase you will find an anchor that is larger than the anchor manufacturer recommends is well worth while but it’s your call whether it can be fitted and carried safely. With anchors, bigger equals more surface area and more weight and both will help you stay put. I know the old guys who sprout the virtues of the old generation anchors are in most cases using an anchor a minimum of two, three or even more sizes up from what the manufactures originally recommended. There is nothing wrong with that mind you, however it is more expensive to fit the vessel out with a bigger anchor and sometimes anchor winch. 

It is important to note there are several manufactures who promote under sized anchors. Why?  basically so they can sell more anchors. Yacht manufactures look at ways to save money so if an anchor manufacturer specifies that a 40' yacht only needs a 16 Kg anchor and the opposition list a 20 Kg as being suitable my bet is that the manufacturer is going to be going for the lighter and cheaper option. 

While all the advertising sprouts the certifications making it all sound wonderful to be classed as a high holding anchor, from our experience we believe the selection charts promote the fitment of undersized anchors. While these anchors are good for a lunch time stop in a peaceful bay they certainly will not allow you to sleep overnight during a stiff breeze, let alone a storm. I think the old guys had it right with upsizing their anchors, they had too, and I believe we need to continue with it and fit an anchor at least two sizes up from what is recommended. 

Staged set up, hooking up the springer to the anchor chain 

Staged again, the loop shown is certainly not big enough but to give an idea of how it will look deployed

Got it right the soft shackle is just on the bottom at low tide lots of chain loop for stretch. 

In conclusion, if your anchor dislodges during a storm you will have to make the call on whether to re anchor during a blow. I know several vessels tried and tried but due to the wind pushing them back and in some cases turning them side on to the wind the anchors would not set. One vessel close to us really had us worried because several times he almost collided with us as he tried in vain to get his anchor to set when re anchoring. During a storm if you have control of the vessel with the motor running now may be the time to hold her nose into the wind and tread water until the blow eases. Go for a drive as you wait, it’s got to be better than exhausting yourself and crew. As we have experienced time and time again voices get raised and fingers have sometimes been put in the wrong place at the wrong time due to the stress and anxiety of the situation when trying to anchor in difficult circumstances which doesn’t do anyone any good.

Poor performance of some anchor winches

During the storm one thing that did turn up as a factor in the problems people faced was the poor performance of some anchor winches. Most of this turned out to be due to lack of maintenance or delayed repairs. If you are having an anchor winch problem that requires you to jiggle wires or the winch doesn’t stop when hauling in and trips the circuit breaker when the anchor is driven home, fix it before it catches you or someone else helping you out. If you’re in a blow by the time you get to the hospital most of the time they won’t be able to sew that finger back on. There were a lot of different winch problems on the night in question and I know of one boat becoming a figurehead on the bow of another boat because his winch failed to pick up fast enough. The reason it was so slow was due to lack of winch maintenance. The maintenance for this winch was to simply remove the shaft clean off any residual sand, mud and organic matter and then grease the bearings and moving parts on a six monthly schedule. An easy but slightly dirty job, but in five years it had never been done.

Check and grease your electrical connections on the winch regularly, don’t use Vaseline or a lanoline based grease for this job due to the low melt point, it will just become liquid and run off the terminals the first day in the sun. Use a heavy duty marine grease and smear it on after making clean dry electrical connections. This will stop moist air entering the good clean connections creating corrosion. A small note: marine wheel bearing grease works a treat because it’s made to get hot and not turn to liquid.

Get yourself a spare hand controller if your winch is set up that way, the failure rate of the plugs, cables and buttons is high enough to warrant an easily plug in hot spare. Make sure the plug and sockets of the hand controller are water tight, some are just splash proof, and that just doesn’t cut it on the front deck or in the anchor locker of a cruising boat in a storm. All plugs and hand pieces should have an IP number, this rating will be an indication to how water tight the connection will be. The IP guide states that IP67: No ingress of dust; complete protection. Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water up to 1 m of submersion. However this will mean the housing and the plug have been assembled as per the instructions, that is the wire going into the plug back shell and the case/buttons must have all the rubbers/O-rings etc to attain water resistance.

A sad sight unprotected anchor winch relays removed from the chain locker

Get under the deck or inside the winch cover to check solenoid connections, these should be assessed on a regular basis, this doesn’t take a lot of time, a quick inspection and jiggle the wires and connectors should spot any corrosion or water ingress that will then require repair. If the vessel is new to you or you have had work done make sure the forward/reversing solenoid is wired correctly. One vessel had a miss-wired solenoid block and while it still worked it didn’t work very well. Unfortunately this work was carried out by a paid professional who was either colour blind in a hurry for the next job or just wanted to get home. A note: if you’re on an extended voyage offshore get a spare set of anchor winch solenoid(s) in the spares kit, due to the variations in solenoid(s) they are not available everywhere off the shelf.

The large foot operated winch control buttons installed in the fore deck can also fail if the installer uses too much sealant causing a blockage of the drain holes. Without drainage any water/condensation remains trapped and will quickly cause enough corrosion to stop the switch working.

As far as I can see, most of the catamaran owners have this snubber/bridle thing down pat due to necessity, but without the same necessity unfortunately a lot of mono owners both sail and power are missing the point. While some catamaran owners do from time to time use the wrong type of rope on the snubber or perhaps tie off a little too short it’s usually the mono-hulls that don’t have long enough or the right type of snubbers or in some cases don’t have an effective snubber at all.

A week after writing the majority of this, we were anchored in a reasonably crowded anchorage. Although crowded there was a fair amount of room, and the bottom was good holding sticky mud in six metres of water. Because I have snubbers and anchoring techniques on the brain at the moment I took a little more notice of the vessels around us. I am sorry to say that of the thirty or so vessels in the anchorage only a few had anything that looked remotely like an effective snubber anchoring system. One vessel was using what looked like an old dock line rubber mooring springer. Very few had enough of a chain loop to allow the snubber to stretch effectively, so I can only surmise the short rope in use didn’t have much stretch in the first place. I also noticed two vessels had very short lines (300mm) in use that would only be good to take the strain off the anchor winch. Two vessels were using silver rode, after watching them anchoring I would guess they laid out about 8 to 10 metres of eight millimetre chain then a lot of rope. I could go on but it would be much of the same with small changes in snubber rope diameter etc. After a particularly nasty storm several vessels were not where they were before the storm. I observed the usual suspects, plows, deltas and claws were retrieved from the bottom when they pulled their gear up to re-anchor. Luckily there was no collisions but I watched two vessel take notice when there old neighbors re-anchored in front of them, funnily enough they then hauled anchor and moved a safe distance away.

Oh yeah, so what’s my schema? Hopefully to make a people stop and think, can I anchor a little safer than what I am doing now? And in doing so remove the grief that comes from being blown backwards through a crowded anchorage at three in the morning, with your wife waking you up to ask you why everyone is leaving the anchorage yah better get up and have a look!