Anchoring and Wind Strength?

Richard10002

Richard10002

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At what level of wind/waves do you need to be sure your anchor is dug in?

I am finding that at as little as 9 or 10 knots of wind, the boat is pressured by the wind, and I'm sure we would drag if we werent dug in.

By 15 knots or so, she yaws about and stretches the chain quite substantially, although I'm not sure if it becomes straight all the way to the anchor.

All of this in a sheltered anchorage with very little in the way of waves or swell.

At 13 knots, gusting 17 knots, with biger waves/swell, (1.5m?),I watched other boats dragging past me at 4am on morning, whilst we held fast.

I only ask as the top end of a Force 3 sounds quite light to be worried about the anchor, particularly for some people on a "lunch stop".
 
I would say you should always be sure you have deployed enough chain on an appropriate size and pattern of anchor for any conditions that might prevail. With the right tackle and the right technique you should be OK in quite severe conditions; we have anchored quite securely in wind gusting to 55 knots on a number of occasions and on many occasions in steady 30knots, gusting 40. That's usually with two ploughs of 1lb per foot of boat length and appropriate chain. We used 90' or 6:1 whichever is longer, typical anchorage depth is 15 -20' and sand. For more moderate conditions we used one anchor, but same scope applies. We always make sure the hook is dug in.
 
I would suggest that unless you have stopped for dinner/other reason of short duration that you always make sure your anchor is dug in . I always lay out the chain and then increase reverse power to really test if my anchor will hold . I dont really take into account that wind may strenghen although I always lay out more chain than needed probably .i f the wind does increase I will always let out more chain if cirumstances allow and can be confident that because I have tested my anchor on intial deployment It will hold .I have observed a number of fellow yachties who seem reluctant to pull on the anchor using engine power to any great extent .This is false security IMHO .Give it a good steady pull in reverse and be confident you will stay put should the wind/tide etc increase .
 
'At what level of wind/waves do you need to be sure your anchor is dug in? '
All wind and tide conditions require the same amount of care
and attention.
There is a lot to be said about 3 to 1 for chain and 5 to 1 for chain n warp , but if to shallow 6 -9ft there is not enough scope so more on the sea floor the better if you are not going to foul other boats.
 
Well, there's a lot of difference of opinion on this forum about what type of anchor is best. You've given an example of yours holding when others were dragging; seems like a good recommendation for it.
 
Can you expand on your comment that about 15kts "she yaws about", pls ?

To me this indicates that there's a lot of windage to one side of the attachment point of the anchor chain to the boat, which causes the boat to move to one side and then the other. Would adding a small riding sail aft of the underwater pivot point help reduce the yaw ?
 
We use an old dingy jib, from a boat jumble, run up the back stay to prevent such yawing - works a treat. We sheet it to the coach roof hand rail.
 
Having been almost clueless in terms of anchoring in May of this year, our summer trip experiences, and reading here, has brought me on leaps and bounds, so I wasnt really asking what I need to do to anchor securely, although that is how it must have read - digging in and plenty of rode, of the right type, seems to answer that question.

Methinks I wasnt clear enough with the question, which should probably have been put more as an observation.

I guess I was really commenting that I have been quite surprised at the tension in the anchor chain at what seem to be fairly light wind strengths e.g. top end of a F3. Given that some people will drop the hook for lunch, without digging it in, I thought it worth a comment.

My comment was due to a recent thread on the mobo forum where Tug Wilson was asking for advice on anchoring as "he hadnt got a clue".

Lots of advice was given, including setting/digging in, and one poster responded:

"What are we trying to do here? anchor for lunch, or make sure it doesnt drag in a F8" (or something like that).

Given our experiences, it would seem that we are actually making sure we dont drag at the top end of a F3 and higher.

In fact, I'd better get over there and make the point - which is where it should have been in the first place.

On our Plough - it sets well in the right kind of sand and mud. It will not penetrate weed or grass, even if it's fairly short. I'm not sure about penetrating hard sand, or its' holding in soft sand. On the whole, I dont have complete confidence in it, but if I've reversed on it to about 2000 revs, and snorkelled over it, and seen it dug in, I'm happy.

Cheers

Richard
 
I think all anchors are compromised in their design to cope with the varied ground conditions, such as you have mentioned. There's no truly polyvalent one. (Gasp, shock, horror!)

Would it be worth identifying your most likely anchoring conditions, and rigging the main bower anchor to be the type which copes best with, say, sand/mud, or weed / rock, and then have a second one for other ground conditions.

FWIW I have a CQR rigged ready to drop from the windlass, a Danforth on the second chain, and a fisherman made fast to the pulpit at one side. But then I also wear belt, braces, and a piece of bailer twine to keep my trousers up... /forums/images/graemlins/grin.gif
 
[ QUOTE ]
Can you expand on your comment that about 15kts "she yaws about", pls ?

To me this indicates that there's a lot of windage to one side of the attachment point of the anchor chain to the boat, which causes the boat to move to one side and then the other. Would adding a small riding sail aft of the underwater pivot point help reduce the yaw ?

[/ QUOTE ]

As always, our bow pays off with the wind and, funnily enough, I got the storm sail out this afternoon to see if I could do something with it on the backstay - but then I found the portable generator, so messed about with that for a short time, and ended up achieving SWEET FA <g> We'll see what tomorrow brings.......
 
[ QUOTE ]
I think all anchors are compromised in their design to cope with the varied ground conditions, such as you have mentioned. There's no truly polyvalent one. (Gasp, shock, horror!)

Would it be worth identifying your most likely anchoring conditions, and rigging the main bower anchor to be the type which copes best with, say, sand/mud, or weed / rock, and then have a second one for other ground conditions.

FWIW I have a CQR rigged ready to drop from the windlass, a Danforth on the second chain, and a fisherman made fast to the pulpit at one side. But then I also wear belt, braces, and a piece of bailer twine to keep my trousers up... /forums/images/graemlins/grin.gif

[/ QUOTE ]

I've already decided that I'm going to buy a Rocna or a Spade when we get to Malta, (mostly based on Morgan Clouds' web site.

That should cover most situations, other than rock or thick kelp, where a fisherman may come into it's own.
 
[ QUOTE ]
We use an old dingy jib, from a boat jumble, run up the back stay to prevent such yawing - works a treat. We sheet it to the coach roof hand rail.

[/ QUOTE ]

Brilliant idea - I'll look out for one!
 
Last year I got aground in Newtown Creek and tried to kedge us off using a Danforth with a 45 metre rope and about 5 metres of chain. The Danforth was very impressive and didn't shift even though I bent the windlass handle trying to get free.

ps despite holding so well the Danforth was quite easy to break out with a vertical pull when the time came.
 
Js48...

Are you using those two plows on one rode? Or on two at 45degrees?

I have been thinkin bout using our fortess clone with maybe 2/3 meters of chain and if we are expecting a bit of a blow runing that in front of and attatched to our main CQR;; ie in series....verus running out a second rode.

How do you get on with that, I have heard of other people doing it but not much comment, strikes me as a potentially good solution. I would have thought that 2 anchors in series on 50 meters chain would pretty much holdanyting at 6:1.
 
Richard - we always dig the anchor in using reverse. The windage on a 44 is considerable and in the short time we've had her we've already learned to increase our scope ratio to at least 6:1

Simon
 
Hello Simon, and a belated welcome to the M44 club!

As soon as I read your post and profile my gut told me you must have bought Richards' Hana, (but had to do a bit of searching, cause she's now called Marmalade - after a '70's kids TV character? a cat?).

Lo and behold,

http://www.ybw.com/forums/showflat.php/Cat/0/Number/1526009/page/0/fpart/2/vc/1

a whole thread I missed whilst swanning around the volcanoes of Italy and Sicilys' Aeolian Islands, (anchoring like there was no tomorrow!).

Well done with the purchase - It seems like every time I've had a problem, or a purchase to make, Richard had already bought and suggested where/what to get, or he had already experienced and resolved the problem. With that, and Nicks comments having seen Hana, i'm sure you will have relatively trouble free and enjoyable sailing.

I tend to use 4:1 quite successfully, increasing to 5:1 or 6:1 if I get a bit nervous. maximum wind to date, (at anchor), has been about 17kts with 1.5m wave/swell, so not really a big deal, but big enough to cause other boats to drag - I'm not certain it was a problem with their anchors, more the inclination of many skippers to drop the hook and chain and think that's all you have to do.

Whenever I swim to look at our anchor, I usually have a look at any nearby. Constantly amazed at how many are just sitting on the bottom, or even dragging through weed, (saw this on a charter bavaria which had about 1.5 x the depth of chain out, and the anchor towing a clump of weed along the bottom).

Any queries about the boat, ask away - I think we all take great delight in being able to help, and I'm sure what goes around comes around.

Richard
 
[ QUOTE ]
At what level of wind/waves do you need to be sure your anchor is dug in?

I am finding that at as little as 9 or 10 knots of wind, the boat is pressured by the wind, and I'm sure we would drag if we werent dug in.

[/ QUOTE ]I think you've answered your own question, other than the obvious imperative that the anchor should be set regardless. Relying on dead-weight is what you do when you have a one tonne mooring block on the other end of the chain, not a temporary anchor. If it cannot be set for whatever reason, one is not anchored - one is engaged in a form of drifting.

As you have found, the forces do not have to be high for the anchor to be given all the work.

As you may have also deduced, looking at other boats' set-ups is just as good a way of working out what not to do, as often as not.

[ QUOTE ]
I think all anchors are compromised in their design to cope with the varied ground conditions, such as you have mentioned. There's no truly polyvalent one. (Gasp, shock, horror!)

[/ QUOTE ]May I point out that unless you have extensive experience with every single type of anchor in the world, this statement is completely unfounded. From your mention of your CQR, Danforth, and Fishermans, I might comment that any experiences with these is likely to lead you to such a belief - but that this knowledge of anchors so outdated in no way applies to others.
 
I'm guessing that your craft has a relatively high bow section and it's the windage on that that causes the yawing. We have the same trouble on Rival Spirit and we have found a couple of solutions.

One is to use a pair of anchors in a V formation this is particularly good in a blow, say 30 knots+.

The other is to run a line from the anchor rode, say about 5-8m from the stem and bring it back to a cleat at midships one side or the other and tighten up a bit. This causes the boat to sit at one angle or another to the wind and stops the yawing, this is a good solution in lighter winds.
 
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