Carry on Anchoring' ...Does Size Really Matter ?

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Carry on Anchoring\' ...Does Size Really Matter ?

Everone knows how you use the chain is far more important than the size of anchor? /forums/images/graemlins/grin.gif

Or is it ?

I think my CQR type anchor may be too big for my little yacht and would prefer a smaller (but equally effective) one.

I have heard there are charts to consult?

What benefits (If any) are there to having a 'bigger' anchor over and above the requirements for your boat?

Any Ideas?
Thanks
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Have you considered replacing it with a new generation anchor? Like say a Rocna - or, say, a Spade?

/forums/images/graemlins/tongue.gif /forums/images/graemlins/tongue.gif /forums/images/graemlins/tongue.gif

(runs)
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Did you think of that all by yourself ... /forums/images/graemlins/grin.gif
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

[ QUOTE ]
Everone knows how you use the chain is far more important than the size of anchor? /forums/images/graemlins/grin.gif



[/ QUOTE ]

As Billy Connolly would say:

Getafe out of here!!!
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Do not ye titter! (or words to the effect) ...tis an honest injun sailing question! /forums/images/graemlins/tongue.gif
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

[ QUOTE ]
Did you think of that all by yourself ... /forums/images/graemlins/grin.gif

[/ QUOTE ]
Yes, but it took me a few minutes /forums/images/graemlins/frown.gif
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

OK I'll bite

If it aint broke dont fix it. Why would you prefer a smaller one? What makes you think it is too big for your boat?

I'm reasonably sure that bigger will hold better.

e.g. the recommended Rocna for my boat is 25kg, but if I were a round the world anchoring cruiser, then 33kg is recommended. If bigger wasnt better, that wouldnt be the case.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Agreed, but, in this instance ...Tis Broke!

Shackle on anchor too big for roller so have to lift anchor up and over, now I am fairly strong but this is not something I should ask crew nor really want to do myself when solo sailing.



Therefore I will either saw (as seized) the shackle off and replace with smaller/different one or, when pondering this checked out size of other anchors on yachts, mine is larger than other yachts (for example my 24.5 ft vs 38 ft) which appear to have have smaller or same size anchors.

Hence my questions
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

MMM! I see the problem - that would be a ballsache and a half!!!

How heavy is your anchor - my CQR is 45lb on a 14 tonne Moody 44.

What size chain - mine is 10mm

Have you looked at a Kong connector - very streamlined

Had to angle grind my previous connector off.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Yes this is a problem on all CQR's but the solution is simple - replace the dirty greate bow shackle that is standard with an allen key type in stainless the are stronger and less bulky so will then go through the roller without snagging. Also much cheaper than a new anchor.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Yes obviously the first step is to replace the shackle with one that will work with the bow roller. Now if the anchor is too big you will know cos it is too heavy to lift/retrieve. In other words the biggest you can manage is best.

It seems to me that in fact the anchor is more important than the chain.
The role of the chain is to ensure by its weight that the pull on the anchor is as close to horizontal as possible. But the anchor is there to grip the bottom. Note an anchor is retrieved by lifting so that the pull becomes vertical or near to it and the anchor releases. So to work it must be pulled horizontally.

A chain which is heavy enough will achieve this horizontal pull. Many of us in fact use only a section of chain before attaching a rope.
Hopefully the section of chain is heavy enough to provide the near horizontal pull providing that the rope is long enough.
Obviously the longer the rope, the further away the boat is the smaller the angle to the bottom so closer to horizontal the straight line is without relying on the weight of the chain. If you have weight then the chain falls in a curve more horizontal at the bottom and more vertical at the top than the straight line between your boat and the anchor.

So general rule of thumb is a chain 3 times as long as depth of water while a rope with some chain 5 times as long as the depth of water.

So while it is hard to quantify the chain if it has adequate weight considering the tug of the boat and length of chain/rope will not affect the holding power. Only the anchor can do that.


So back to the original question it is a matter of balance. A tiny anchor with long V heavy chain won't necessarily hold while a huge anchor with no or little light chain won't hold very well either. Enough weight of chain however will enable the anchor to work at its best.

So if you can, the best trick is to dive down and observe your anchor doing its thing. If it has adequate weight of chain/ long enough rope/chain then the first metre or so of chain from the anchor will remain on the bottom or even buried despite the pitching of the boat and the wind/ tide drag. An anchor too small will remain horizontal and will be seen to be dragged along under the sand under full load.

All as I see it olewill
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

I would say that if the ground is difficult, a bigger version of any type of anchor would have a better chance of holding than a small one of the same make. So always choose the heaviest one you can manage.

A better chance of a good nights sleep.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Put it this way - what is the gain by downsizing, or splashing out a lot of dosh on an alufoil anchor?

Thought not.

Size does matter, when having a really good anchor matters.

The big unknown is; when will that need arise? Now that's a question no one can answer...

PWG
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Sorry Will, have to dissagree to some extent. yes the weight of the chain provides a horizontal pull, but the heavy chain also contributes to what is called the canterary (sp?) efect, where by when the boat is taken by a gust, it has to move a lot of chain before the snatching force is applied to then anchor, and thus it is much reduced. With all or mostly rope, the thing pulls tight instantly exerting a much higher peak load on the anchor, and it is after all the peak load that will dislodge the anchor.

Having said that you do need something about the right size in terms of an anchor, you wouldn't catch HMS Illustrous with a 20kg Rokna evn it it was on the end of a lot of chain...
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

It's useful to read Alain Fraysee's Site to understand the dynamics of anchor rodes. You'll note that, at anchor pull-out forces, the catenary has disappeared. So the most effective way of damping peak loads is by using a good length of springy nylon rope in addition to any chain.

One way of doing this is to extend the length of your snubber - I use up to 20m of snubber, gives me 2m of elasticity.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

If it's the shackel that's the problem (as it was with my boat- b****y thing always got jammed in the bow roller) then a stainless anchor connector / swivel is the best option. Was the best A$35 ever spent. Comes through cleanly every time. There are several sizes available and come in single or double swivel.
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

------- So always choose the heaviest one you can manage. -----

Unfortunately, it doesn't work like that. How come Fortress come out very well in most tests, when they are always the lightest? And how does a 50 lb fisherman compare with a 25 lb Delta? Probably not very well, dependent upon the bottom.

This is a complex subject, best answered by another anchor test and a long thread on this forum /forums/images/graemlins/wink.gif
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

[ QUOTE ]
A chain which is heavy enough will achieve this horizontal pull.

[/ QUOTE ] That would have to be an enormously heavy chain. See my post above.

The 'horizontalness' of the pull (at anchor snatching loads) is mainly a feature of the scope you've let out; the effect of weight on the rode angle at the anchor at that sort of tension is small.

Most anchors can dig in and hold if their shank is not more than 10 degrees elevated from the bottom. That's equivalent to a 6:1 ratio between [amount of rode out] and [water depth + height of fairlead] . Some anchors need more scope, others less.

You can (and should) test your set-up to see what scope you need with your anchor to dig it in, and then to hold with full astern. Of course, you've probably already done that . . .
 
Re: Carry on Anchoring\' ...Does Size Really Matter ?

Big weight might be best but no good if it does your back in manoevering it on the roller. Thus I changed from a 15kg Bruce to 9 kg aluminium Spade. Much easier to handle. Retailer advised caution using aluminium as main anchor because shaft has been known to bend. Thus I took manufacturer's advice and use 10 m snubber. After attaching that I lower plenty of chain on to sea bed to give catenery effect and reduced yawing. No dragging this season in Turkey/Greece
 
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