Using 2 anchors.

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Sybarite

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As a follow on to the recent anchoring post.

When you expect to have bad weather, the usual wisdom is to put out two anchors in a V setting. Assuming there is a fair bit of chain on both, how do you go about dealing with two anchors with one windlass in gale or near gale conditions?

I have never had to do it in anger but, if I had to, I would probably use the two anchors in tandem.

John
 
Well, I've at various times tried all of these.

The "fork moor": two anchors set at an angle of 30 - 60 degrees to each other can be handy when space is limited, but does give some extra hassle. The logistics aren't too difficult however: when recovering, let out scope on one anchor (normally the main bower) and recover the other; once that's stowed, deal with the other in the normal fashion.

I've used tandem anchoring (in the conventional sense) with my previous boat and it worked OK, but I never tried to recover in very blowy conditions. I currently occasionally use a form of tandem anchoring in difficult bottom conditions (weed / rocks) when I shackle a small "Rockfish" grapnel and a few m of chain to the crown of the Delta. It seems to work, but I've not used it in extremis. Recovering is easy as the Rockfish is tiny.

The worst weather I've anchored in to date (F9, veering 270 degrees) was survived using the main bower only (16kg Delta). I could have put another couple of m of chain out, but didn't (not quite sure why). Getting it back aboard afterwards was not easy. (Story here: 2/7/05 - 4/7/05 http://www.yotblog.com/DaveS/785/)
 
I haven't tried tandem anchors, but I have put out and retrieved 2 in 30kn. I have a bower on all chain, and a secondary with 10m chain and 60m rope. What I did was to lay out and set the bower and all the chain first, then motored up to about 20m to the side of that anchor and dropped the secondary. I fell back and set that one before coming tight on the bower, then let out the rest.

Laying is the easy part - it's the retrieving that is harder! Because I use snubbing lines anyway, the chain or rope is tied off to deck cleats and not left on the gypsy, so you can motor forwards and winch in one of the anchors (I did the secondary first because I didn't want the nylon rode getting under the boat).

When the first is all stowed, then transfer the bower to the windlass and away you go as usual. It would be a b****y sight easier if you don't have to do it on your own, and have a good powered windlass! It took me about 40mins in that wind, with a 4-6' swell, but a lot of that time was spent scuttling back and forward from the cockpit to motor forward to put slack in the rodes.
 
IMHO Tandem anchoring is the only way to do this safely.
We lay the first anchor, allow it to set, that is attached to the crown of second anchor, with a poly line between the two and 30 feet chain. Then lay out main chain.
When it comes to retrieving them you can use the poly line on the windlass to make things a whole lot easier...........
we have 45lb CQR, followed by 65lb CQR.
Need lots of room to swing but sets as solid as a rock.

Theres a good description of how to do it in the RCC Chile pilot guide........
 
In Male (Maldives) recently we had to use 3 anchors due to local boat anchoring techniques. Used main anchor with 50M chain then two anchores at approx 30 deg with 10M chain then 30-40M nylon. Depth 7M
To retrieve, main anchor first, extend one anchor rode then motor to the second anchor, retrieve, then same with third. held us steady as a rock in 50Kn+. Aphrodite 42 ketch tends to wander a bit. Main anchor, Bugel 25Kg, seconday anchor Bugel 27Kg, third anchor 18Kg Danforth. Tony
 
I use two anchors in a forked moor very often, I find it very secure whilst reducing yawing. The only times I've tried tandom anchoring I've got into a tangle and have been embarrassed by the excessive swinging room required. The former problem is probably operator error and the second occurs because anchorages fill up when bad weather threatens and swinging room is at a premium. In fact your anchoring system should be such that in all but the most extreme conditions a single anchor will do the job. The second anchor is to give you two shots at getting a good set and to limit yawing and swing room.
Setting and retrieving is not problematical with a good windlass; without one it can be very hard work.
All the above in my opinion, of course.
 
Many thanks Craig and to the others too.

Up until now I have always handled anchorng by hand; 31' boat under 4 tons. The next boat will be long keel and nearly twice the weight. I was therefore interested in the actual manipulation of two chains on one gypsy. It is set up so that the bow roller is offfset to port and the gypsy is lined up with it. This means that the rope windlass is on the wrong side - even farther to port to handle a line to starboard of the forestay.

My understanding now is with the right anchor one would require exceptional circumstances to have to use a second and, if so, it's more reliable in tandem than in V provided the attachment is carefully studied. The rode between the two also needs to longer than the water depth so than you do not have to raise two anchors at once.

Thanks again.

John
 
Using an angel weight to augment anchor

My favoured alternative is to send down an angel weight. I have a 4" length of 6" iron bar with an eye welded to it. It is heavy, but just manouverable with care (about 15kg). Thro' the eye I put a large bow shackle that fits over my anchor chain. I can then tie a warp to the shackle & lower the weight down the main anchor chain - having anchored in the normal way first of course!

What this does is put a very heavy weight on the sea floor behind the anchor. It produces a markedly deeper catenary so that the pull on the anchor is almost horizontal (equivalent of loads of extra chain). It also increases the total weight on the sea bed adding to simple drag resistance AND reduces the swinging area required in most circumstances (severe conditions will cause the angel to drag around, but the deeper catenary reduces total radius). Finally, the weight acts as an anti-snatch device taking the sting out of waves.

To recover, in most cases, you will be able to recover the weight by pulling on the rope tied to the shackle. If you have sat on it for several tides it may be tangled so that you need to recover both chain & rope together. I have found this very useful in severe conditions or where there is limited room to swing.
 
Re: Using an angel weight to augment anchor

Rocna put a simple supposition. If you simply increase the weight of the anchor by the weight of the kellet/angel you get vastly improved holding power.

It's a good point and I may have to revise my theory which was the same as yours.

John
 
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