Stolen Kiss

Stolen Kiss

October 28, 2013

Excellent Anchoring Technique for Cyclones

We particularly like this article we found, not that we ever intend to be anchored in a significant named storm....but you never know!

Set for a blow
Foster Goodfellow

Years ago, whilst tucked away in a secure anchorage at Stewart Island, an Englishman shared the secrets of his anchoring technique with me. Charley was sailing round-the-world in his small boat, Aquila Nova. He and his lady had voyaged across the South Pacific and, when we met, had just returned from a visit to the windy Auckland Islands, several hundred miles south of New Zealand in the Screaming Fifties.

Charley didn't have an engine, so he needed to be firmly attached to the bottom when he anchored. He used two anchors attached to a swivel which seemed to make good sense. As a method of weathering high winds, it fit the bill for us, too, because although we have an engine, it is small. Once the winds rise to gale force, we don't have enough horsepower to get us out of trouble. Like Charley, we have to rely on our anchors.

I liked his method of creating an Anchor Mooring because it didn't require any expensive, oversized or hard-to-store anchoring gear. We simply count on the effectiveness of the system and our regular ground tackle.

You need a plan:

Several years ago we opted to stay in the tropics during cyclone season rather than make our annual pilgrimage to more temperate latitudes. New Caledonia - with its French flair, moderate temperatures and monokinis - seemed a good alternative. But our first cyclone popped up within 24 hours of checking in to Noumea. Immediately we were put to the test.

Though we have plenty of anchoring gear - 5 anchors, lots of chain and heaps of rode, it soon became apparent that we needed to look more seriously at our method of anchoring. We decided to employ Charley's technique.

Our cyclone hole, deep inside the Baie du Prony on the southeast side of Grande Terre, was a classic hurricane hole, surrounded by high hills and an S-shaped entrance which closes out the wind and seas. But unlike hurricane holes such as English Harbour in Antigua, there is no soft and yielding fringe of mangroves along the edge. Consequently, you must anchor in the middle of the bay and swing with the wind.

We created an Anchor Mooring using our 35# CQR and our 35# Brittany anchors set on separate chains and joined at a giant swivel. These are laid out 180 degrees from each other, one toward the direction of the wind and one away from it. As a deep low approaches and we determine which way the wind is going to move - i.e. will the centre pass to the east or west of us? - we set our third anchor (a Fortress FX37) approximately 90 degrees to the line of the two anchors in the direction towards which the wind is going to swing. At the height of the storm we lie to this third anchor, which has more nylon anchor rode than chain and which absorbs the stress and pitching. Meanwhile, the other two anchors and swivel dampen the boat sailing from side to side.

I chose this technique of creating an Anchor Mooring using two anchors joined at a swivel because (1) we don't have enough horsepower in the main engine to move us around once the wind gets going; (2) we needed an anchoring technique that worked with the wide range of wind direction experienced with the close passing of an intense depression; and (3) an Anchor Mooring enabled us to use maximum weight of gear and catenary effect for the area required to swing in - a relatively small area compared to using tandem anchors. Whatever we do has to hold us until the wind abates.

How we create an anchor mooring
Before we start our anchoring routine, we set up the second anchor with its crown hanging outside the pulpit on a line so that we can release it easily. The chain is stacked so it will release from the bitter end (which is attached to a swivel) towards the anchor end - the reverse of what you normally do for anchoring. If this sounds confusing, read on.

To start with, we use three or four times the depth of water in chain on our main anchor, i.e. a scope of 4 to 1 to the swivel. Then we drop the main anchor down in the direction the wind is blowing at the time, with the chain and nylon rode attached to the swivel, and pull it in and set it with the motor. Then, after this first anchor is good and set, we pull the line back in to the end of the chain. A large (1/2") swivel is attached to the end of the chain, to which we attach the chain of the second anchor. Our second anchor has an amount of chain equal in length to the first anchor. We back down to leeward, paying out all the chain and rode.
Once the chain is stretched out, we release the second anchor from the bow. After it drops to the bottom, we pull ourselves back to the swivel in the centre, using the anchor rode attached to the swivel. (See Illustration A)

The next step of the operation is to turn the boat around, using the kick of the engine, and use the engine to pull in the second anchor to windward. (See Illustration B) Having done that, we go back to the swivel one more time, pull it to the surface (which is very hard work as we now have 300' of chain down, 150' in each direction). We attach a second backup nylon rode to the swivel for extra security.

At this point two nylon rodes lead from the swivel over the bow rollers to large cleats, with large reinforced one-metre length vinyl hoses over each rode as chafing gear. This may sound time consuming, but once we worked out the drill to put the anchors down, it took only 20 minutes to set the second anchor.

What was perfect about this setup was that, before a storm arrived, the boat could swing around in a number of directions as wind and tide changed, and the swivel allowed the boat to go around and around without getting fouled. (See Illustration C) Then we'd wait until we knew if the storm system was close and on which side it was going to pass. Once we determined if the wind was going to veer or back, we laid out a third anchor in the direction/quarter that the wind was going to shift. On that anchor (an FX37 Fortress), we used 250 feet of new nylon rode and 50 feet of chain so that it would have a lot of stretch and be easy to deploy from a dinghy.

Managing the anchors during the storm:
As storm approached, we lay to the first anchor. Then, as the wind came around and reached its peak intensity, we started laying on the third (FX37) anchor. During this time we kept tension on the rode so that we were chiefly pulling on the third anchor. The swivel and chains to anchors 1 & 2 lay almost directly underneath the boat on 50 feet of line with all the chain keeping the centre low. These two other anchors were mostly responsible for keeping the bow of boat still, and we experienced little shearing motion on the anchors. Finally, as wind came around to the westerly quarter, we started paying out both rodes until we were laying on the second and third anchor as if they were in v-formation.

Pulling up the anchor mooring:
To pull up our anchors, we lifted the swivel to the surface and attached a chain hook and safety line to the 2nd anchor chain. We undid the shackle holding it to the swivel (being careful not to drop the pin!) and then attached the shackle to a nylon rode. Now we could pull up each anchor separately. (See Illustrations D & E) The third anchor can be retrieved independently before or after retrieving the first two.

How to create an anchor mooring if you have one piece of chain:
If you have one piece of chain 200 to 300 feet long, the best solution is to cut it. You can then use a chain joining link sized for your chain to rejoin the chain afterwards. The joining link should have the same dimension as your chain links so it will work in your windlass wild cat and be as strong as the shackles at either end. The alternative, according books and articles I have seen, is to use a shackle to attach the swivel in the centre of your long length of chain. But nobody explains how you can possibly do this except by using the smallest of shackles, small enough to get through the hole in the chain link but probably not strong enough to survive storm force winds.
You may try a large shackle around the whole chain but you still have to seize the shackle in place so it cannot travel up or down the chain. If you decide to use one piece of chain for an Anchor Mooring, you must have a trip line to one anchor to be able to pull the anchors up. Two separate pieces of chain for the Anchor Mooring work best.

What we used on fellowship:

First anchor - 35# CQR with 150 feet of 5/16 (9 mm) high-test chain, 200 feet of 5/8" nylon rode.

Second anchor - 35# Brittany anchor with 150 feet of 5/16 (9 mm) chain.

Third anchor - Fortress FX 37 (19# Danforth-type) with 50 feet of 5/16 (9 mm) chain and250 feet of 5/8" nylon rode. Light weight and easy to set with dinghy.

Fourth Anchor on stand-by and on deck - a D2000 or 20# Deepset Danforth with 75 feet of 8 mm chain and 250 feet of 1/2" nylon rode.

Fifth Anchor - 12H Danforth with 45 feet of 1/4" chain and 250 feet of 1/2 inch nylon rode.
(You never know when your neighbour might need to borrow one!)

Swivel - 1/2 inch size swivel. Remember to use the round forged end to attach the two anchor chains to as they will be pulling at right angles to the swivel and use the D-shaped end for the nylon rode as/so it will pull in line with the swivel.

Shackles - High tensile proof-tested galvanized steel shackles with appropriate Safe Working Loads (SWL).
1/2" - pin diameter 15.9 mm. SWL 2000 Kg. - for 5/8 rode to swivel.
3/8" - pin diameter 11 mm. SWL 1000 Kg. - for 5/16 or 10 mm chain.
5/16" - pin diameter 7.9 mm. SWL 750 Kg. - for 1/4 or 8 mm chain.
Anchoring for storm conditions:

Single Anchoring 
When anchoring for storm conditions with a single anchor, you need to use a larger anchor - at least one or two sizes larger than recommended. One recommendation is to have 50% chain and 50% rode or, if you are using all chain, multiple spring lines and good chain hooks. One disadvantage with this technique is the weight and stowage of a special storm anchor, used only in storm conditions. Any anchor over 45 lbs. is hard to manage on deck. In addition, you need quite a bit of swinging room. Thirdly, a single anchor is subject to a lot of stress from the boat sailing back and forth on the rode. Finally, an anchor two sizes larger may warrant an increase in your chain size which entails all the problems of windlass compatibility and storage.
Two anchors in a V-formation Here, the anchors are set from 45 degrees to 60 degrees apart, using the main anchor in conjunction with a second anchor. It is relatively fast to deploy and reduces sailing on the anchor. This second anchor should be on 50% chain and 50% nylon rode which is easy to stow and deploy. You do need to have a bow roller capable of handling two rodes. The effectiveness of the v-formation diminishes as the winds shift, putting the stress onto one anchor. This anchoring technique is the most common one for storm anchoring but is not a desirable choice if the wind decides to shift right around the clock - as when an intense depression passes close to your location.

Tandem Anchoring 
Using tandem anchors, two in a row, is a very reasonable option because you increase your total holding power and weight while using your regular anchors and chain. Its disadvantage is that setting and recovering anchors can be complicated, depending on how you attach the them together. Tandem anchoring does not dampen sailing on the anchor and is not the best for radical wind shifts of 180 degrees, as happens with the passage of a cyclone directly overhead.

Earl Hinz in his book on anchoring recommends that tandem anchors be set "four fluke lengths" or about five feet apart. I disagree. If they are set too close together, the anchors could become fouled or entangled. However, if they are set too far apart, they take up too much space. The distance between the anchors should be about one to two times the water depth - this minimizes the chance of the anchors fouling on the way down (or up).

There are two approaches to Tandem Anchoring.

The first involves shackling a length of chain to the head of your main anchor and attaching a second anchor. The length of chain is open to debate as some sailors use only a few meters of chain with the thought that the first (main) anchor ploughs clear the bottom so the second (tandem) anchor can get well into the bottom. This may be a good idea in very weedy bottoms.
For storm anchoring I prefer to have a greater distance between the two anchors. This prevents the anchors from becoming tangled with each other and/or the rode while deploying them. If you use a length of chain equal to (or a bit longer than) the depth of water you are anchored in then, when you anchor, the tandem anchor will touch the bottom and enable you to back down and stretch out the chain before the main (1st) anchor reaches the bottom. This should ensure that both anchors are not tangled in the rode and that each has an opportunity to dig into the bottom. It would be reasonable to expect that the length of chain between the two anchors would not be subjected to the same snatch loads as the chain closer to the boat so you could use a small size for this length. If you make the length between the anchors too long, you may have problems with other boats fouling your anchor.

A second approach to Tandem Anchoring is to shackle your tandem (2nd) anchor after your main anchor using a short piece of chain (1-3 meters). This method means you can shackle and unshackle this 2nd anchor relatively easily. The drawbacks are: 1. How do you effectively attach the shackle to the chain? and 2. How do you ensure that the 2nd anchor won't entangle the rode? Additionally, only a burying-type of anchor such as a CQR or BRUCE could be used as a tandem (2nd) anchor because a Danforth-type would surely catch on the rode as it drags back and forth over the tandem anchor.

Anchoring tips

Safe Depth If you have your pick of the anchorage, choose deeper water rather than less to gain maximum catenary effect from your anchoring gear. Also, areas that have less water have the disadvantage of being more attractive to other boats and hence became more crowded. Other boats dragging are often your biggest worry.

Swinging Room Many hurricane holes are crowded when there is a cyclone. Try to use an anchoring technique that will keep your swinging room at a minimum.

To avoid fouling by other boats coming to anchor after us, we marked our anchor with a light line and a small buoy attached to a dinghy anchor. We preferred to use separate marker in the area of our anchor (rather than a line attached directly to the anchor) in case someone fouled the marker and accidentally pulled up the anchor!

Strip It cannot be stressed enough: To increase the holding power of your anchor, the easy and cheapest thing to do is reduce the boat's windage. Strip as much as you can off the deck. Lee (or weather) cloths around the cockpit should be easy to remove (i.e. not laced with 1/2 mile of cord!). Ours are designed with a top flap that wraps around the life line with quick-release twist lock fasteners. Light line holds the bottom corners.

The main sail should come off in extreme storm conditions such as those experienced during a tropical cyclone. Under those severe conditions, sailing off the anchor and out to sea is not the final option to facing a storm at anchor. You must hang on, no matter what. Take the mainsail off and rest the boom on deck.
Roller furling should be removed anytime a blow is expected at anchor. Saying that, I know few people will. However, a jib unfurled in high winds is highly dangerous, noisy, and costly. It can cause the rig to fall down, the anchor to drag or, at the very least, the sail to shred.

Nylon Rode The nylon rode we use for the third anchor (that we set and relied on at the height of cyclone Drena) was a brand-new never-used piece of line. The other rodes were relatively new, too. New line has additional stretch and it provides more shock absorption than old. New line will also be more resistant to chafe than old.

Stretched-out, nylon chain snubbers may be fine in a 20 knot blow, but are a poor choice in higher winds.
Chain Hooks Chain Hooks are used to attach a snubber line to the chain. The best hardware is a proper proof-tested steel chain hook built to fit your chain-size. Don't rely on inadequate but sexy stainless carabine hooks. They look good, but are designed for lesser loads.

Windage is your enemy in a storm so keep your dinghy off the deck. The best way to deal with the dinghy is to half-sink it with water or with filled jerry jugs and tie astern. Small inflatables can be flattened and stowed. The force of the wind is incredible so remember to tie the dinghy to stout cleats. Friends who weathered super typhoon Paka recounted the tale of a dinghy turning into a kite and flying away with the lifeline stanchion it was tied to and part of the deck attached, leaving a gaping hole in the deck!

Use only high tensile, proof-tested (the ones stamped with SWL) galvanised steel shackles. Shackles are weaker than the chain - which is weaker than the nylon line - so use only the best. Do not use stainless steel shackles. They look nice and shiny and cost so much but chances are you'll tend to use them long after they are worn out. Galvanised shackles get rusty to remind you to replace them every two years!

All large cleats should be thru-bolted with large backing plates even if you are not in storm conditions. It is best to have two separate cleats on the foredeck to use for storm anchoring.
Winches are strongly thru-bolted but in storm conditions when a line is wrapped around the winch, it is still held in check only by the small paws in the winch. For this reason it is best to use only thru-bolted cleats in extreme loading conditions.

Chafe Guard
I used one meter lengths of reinforced walled-vinyl tubing. These could be slipped over the anchor rode and tied in place with a small line. The tube was large enough that I could feed the line out through the tube. A second layer of fire hose (or vinyl hose) slipped over the first hose gives the best protection against chafe.
Barometers A barometer is the best indicator of wind strength. See box on page 47 YW November 96.
Anchor Lights Use an anchor light. When the wind rises in the black of the night, it is nice to know your neighbours know where you are. It's even nicer if you know where they are!

Chain Weight (AKA Anchor Sentinel, Angel or Chum) 
A chain weight is a good idea as it effectively dampens the strain on the anchor by producing a catenary effect. In desperation, a cruiser attached a bucket of rocks to his chain as a make-shift anchor buddy!
To deploy, the weight should be lowered down the anchor rode until it is a few feet from the seabed. To be effective in very strong winds, though, the weight has to be very heavy (more than 30 pounds).
The End of the Chain The bitter end of the chain should be examined before facing a storm at anchor. Splice a nylon line directly onto the bitter end of the chain with enough line so that the chain end can be pulled out of the hawser hole, onto the deck, and the end of the nylon rope fixed to a strong eye inside the anchor locker. This will permit you to cut the chain free in an emergency without getting into the chain locker. The shock load will be tremendous if the winch fails and lets the chain run out so keep the line in new condition and ensure the eye fixed in the anchor locker is very strong. Many yachts are lost due to the anchor chains simply pulling free from the boat. Rope anchor rodes should have their bitter ends tied around the mast and ready to run free.

The anchor end of the chain should be looked at closely, too. The last link on the chain (where the shackle attaches) is often subjected to a lot of wear. It may be best to snip the last link off and start anew.

Be Prepared Before facing a storm at anchor you should prepare yourself and your boat as much as time will allow. Spare anchors and line need to be brought up on deck ready for deploying. Top up with fuel and water, and don't forget outboard gas. After the storm, supplies may not be readily available ashore. Review food stores and have supplies handy. Get all boat gear stowed as if for sea and secure hatches and dorades. High wind may blow twigs and leaves onto the boat, plugging the cockpit drains so make sure they are screened off. If you expect winds in excess of 70 knots, have a dive mask available so you can go on deck to check lines. Research the effect of coastal storm surge and flooding for the area you are in and be prepared.

If your boat is not equipped with a minimum three good anchors and plenty of rode, then head to the nearest marina at the first warning of storm force winds. With good anchoring gear and a solid plan for anchoring, though, you'll be Set For a Blow.
© Sally Andrew April 2005

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