Anchor chain or chain, warp combination ?

[prv]

I wouldnt be too keen. In a strong breeze, the weight would rub and weaken the rope unless you can find a way of attaching it that I am not aware of.

I hadn't really thought about how to attach it, but the chances are it would be a small seizing around the warp with a bit of thin cord from my cockpit stash.

In any case provided you have sufficient scope of rope to allow the pull on the anchor to be at the angle it is designed to take, there is nothing much to be achieved by lengthening the scope unlike with chain.

Sure, but if it's drifting conditions then 5:1 is still quite a long leash in a busy Solent anchorage where everyone else is on chain and staying put.

Pete

 

[lw395]

Agree with you think you are maybe putting too much emphasis on the snubbing effect of the rode. The rode (chain or rope) has only two significant functions, providing the correct angle of attack onto the anchor and being strong enough not to break. Now we (except NormanS) know that the affects of the catenary dissappear in anything over modest winds the rode could even be wire if it was strong enough. The way to snub the anchor is to use a snubber.

Also cannot see the purpose of a chum that is not on the bottom.

I think that's only true in flat water.
If you add in the effect of a swell raising the bow of the boat even say a few inches every few seconds, then the dynamics of the weighted rode come into their own. Also the damping of the rode/weight moving through the water.
This matches with my observations in some circumstances.

 

[Storyline]

I think that's only true in flat water.
If you add in the effect of a swell raising the bow of the boat even say a few inches every few seconds, then the dynamics of the weighted rode come into their own. Also the damping of the rode/weight moving through the water.
This matches with my observations in some circumstances.

Understand what you are saying and suppose it is a bit like the theory of hanging buckets over the side to stop rolling in a swelly anchorage. It would be interesting to hear from those with bigger brains than me just how much the damping effect is increased by having a longer length of chain out. Assuming that there is enough wind to lift the whole length off the seabed then I would have thought that the longer the length the more the damping and the effect could be considerable. Quite how much this makes life on board more comfortable I do not know having always anchored on an all chain rode.

 

[charles_reed]

Modern thinking is that all chain doesn't make you any more secure, the catenary is all pulled out of it more easily than we imagine, and then its lack of stretch means that greater loads are applied to jerk the anchor out. Chain is no stronger than properly-sized rope (8mm G40 chain 40kN, 14mm octoplait nylon 47kN). It's very heavy, and usually stored in the worst possible place for extra weight.

The main benefit is that it's largely immune from chafe, and its drag on the bottom when not loaded means you move around less in light conditions.

Nevertheless, most of us tend to feel more secure with lots of heavy chain out. I know I do, and that's why when we bought Ariam I installed 60m of it together with a 20kg Spade anchor.

Sadly, this has proven to be a mistake. The bow of the boat is now seriously overweight, and doesn't rise properly to the seas. We also have a beard of weed where the water is above the antifoul when moored. So this winter I will be removing most of the chain, leaving only 15 or 20 metres, and replacing it with rope. The reason I'm keeping so little is so that I can still have the big anchor, which I think is more important than having lots of chain just to feel good in some indefinable way.

I think you'll be fine on rope, and if you don't have a windlass you may regret all-chain unless you only anchor in very shallow water. A decent anchor is the important part.

Pete

I concur entirely - I've just ditched 15m of chain and 40m of 25mm octoplait for 50m of 14mm octoplait. The bows of the boat have come up by 70mm, I can get to windward far more effectively and 8mm chain and 14mm octoplait fit the same gipsy and are easy to splice.
When I used to anchor with all chain rode, my boat used to drag about 1 in 5 occasions, using chain and up to 10m of textile on a chain hook I've had 4 drags in 5 years (that about 0.8%).
Mind I had the good fortune for the shank of the So'wester CQR copy shatter and be replaced with a genuine CQR (which has since worn out).
I found that all the "new age" anchors except Mantus recommended a much heavier anchor than the CQR.

 

[charles_reed]

Since I am converting to rope, as described above, having previously always used chain, what are people's thoughts on using a kellet to provide a little drag on the bottom and avoid drifting around too much in light conditions?

Pete

Think you're better off putting the weight in a larger anchor.

 

[charles_reed]

Well, as someone who goes to Scilly with a similar sized boat I can tell you that I used to have a genuine CQR on chain/warp and it was ok there. However, Scilly isn't noted for the quality of its holding ground and I did drag a bit there a couple of times despite having plenty of scope out. The way I got around that at the time was to use an anchor chum (mine is a big lump of lead with a shackle at the top) at the chain to warp splice and this seemed to make a large difference when a blow went through.
I now have a Spade anchor with chain/warp and it hasn't moved an inch every time I've used it. I'm not saying go and buy a Spade but I'm saying you might find one of the modern anchors a bit better there especially as they nearly all reset better than a CQR which can be a pain sometimes.
One of the nice things about having a decent anchor in Scilly is that you can avoid rolling like a pig in St Mary's harbour in bad weather with all the other yachts. Just go and find your own safe spot and you'll be much comfier.

Interesting as I've found the CQR resets better than the Delta. The draw back with both those two is that just at the start of setting they always have a list - if you don't complete the setting process (I use about 80% of full power for 30" with an Autoprop) they are both very liable, with any shift in pull, to come free. It is very much easier, in the Med, to see your anchor.
The CQR does demand far more operator care than the "new-age" anchors and needs >4m to set, whereas the Mantus sets in 1m.
For my boat the recommended steel Spade was far too heavy (for trim, handling and price) and the aluminium one has a history of fizzing away in use. The recommended size Mantus was no heavier than CQR or Delta, far easier to handle than the former and (bought in the US) cheaper than either.
Anyone interested in fact about anchors will find this a very valuable resource http://www.cruisersforum.com/forums/f118/photos-of-anchors-setting-126073.html

 

[charles_reed]

I think that's only true in flat water.
If you add in the effect of a swell raising the bow of the boat even say a few inches every few seconds, then the dynamics of the weighted rode come into their own. Also the damping of the rode/weight moving through the water.
This matches with my observations in some circumstances.

If I may add to your point - my boat was a pig at anchor - in any seas/wind she'd sail around the anchor, every so often sailing up to it and giving the slack chain a good shake.
After looking at Alain Fraysse's work and some e-mails with Alain Poiraud, I started anchoring on chain with 3-10m of textile rode on a chain hook. By leaving a bight of chain between hook and boat - effectively a kellet, the chain never came out of the water until over 28knots windspeed, the boat stopped ranging around and my drags went from about 20% to <1%. As I anchor about 100 times a year this made for significantly better rest.
I'd certainly suggest people look here to recognise that all chain is undesirable in any heavy weather anchoring
http://alain.fraysse.free.fr/sail/rode/dynam/dynam.htm

In practice I find most discussions about anchoring excessively simplistic - it's a quite complex quadratic system which doesn't respond to particle investigation.

 

[Storyline]

.....
I'd certainly suggest people look here to recognise that all chain is undesirable in any heavy weather anchoring
http://alain.fraysse.free.fr/sail/rode/dynam/dynam.htm
.....

Surely that is only true if anchoring to an unsnubbed chain rode. If you use a well designed snubber then the ease of use of chain wins out in my opinion. It takes just a minute or two to recover say 25m of chain if we are slightly unhappy with a set whereas a rope rode would take considerably longer so it may be tempting to make do.

Do agree though that weight in the ends of any boat is not good so we have a system of lockers so that we can move the weight of a significant amount of chain aft away from the bow.

 

[lw395]

......

In practice I find most discussions about anchoring excessively simplistic - it's a quite complex quadratic system which doesn't respond to particle investigation.

Yes, I'd agree with that, I have forgotten a lot of my physics degree, and the maths required for it, but a lot of people do seem to leave out all the awkward factors.
I played around with spreadsheets, trying to get a handle on the influence of the waves on the anchored boat some years ago.
It vaguely reinforced my obervation that you don't need much in the way of waves to make the peak force on the boat much greater than the average.

My first boat came with a Danforth, 3m of rusty chain and a bundle of rope that floated. I added more chain and some weights to sink the rope, rght after our first 'rode around the keel' fiasco.

My first two boats were ex-racers, so the anchor(s) mostly spent its life abaft the mast. Even a sensible weight of anchor and chain up in the bow is very damaging to windward sailing in a chop.
Not having a windlass, arranging things so you only have to lift a modest length of chain is nice. And if the kellet is stowed before the chain comes off the seabed, better still.

 

[charles_reed]

Surely that is only true if anchoring to an unsnubbed chain rode. If you use a well designed snubber then the ease of use of chain wins out in my opinion. It takes just a minute or two to recover say 25m of chain if we are slightly unhappy with a set whereas a rope rode would take considerably longer so it may be tempting to make do.

Do agree though that weight in the ends of any boat is not good so we have a system of lockers so that we can move the weight of a significant amount of chain aft away from the bow.

On the contrary, I'll not go into the theory here but suggest you have a look at the site quoted.

 

[TonyMS]

There is also the question of how to join the rode to the chain.

I have, in the past, spliced my 18mm anchorplait to the 8mm chain. But it leaves a very "sloppy" splice - no doubt strong enough, but vulnerable to chafe. Ann then made a protective sleeve for it, but that meant we couldn't inspect it. So now I use an eye splice on the rode and shackle it with a s/s shackle to the chain. We don't have a windlass, so the only problem is easing the shackle past the fairlead.

BTW we have 29m of chain, allowing us to have only chain on the bottom in any reasonable depth. Works for us.