8mm Anchor chain?

Sail on the Scottish West coast and our previous boat was similar to the o/p (31') and we carried 50m of 3/8" chain. In these cruising grounds it is easy to find sheltered anchorages with depths of 5m or less so we found we always had enough scope. Have to bear in mind though that as Jonathan points out you have to add the distance from the bow roller so if in say 5m under the keel at high water the actual depth to the anchor is 5 + 2 + 1.5 (in our case) so we regularly lay 40m. In 20 years we rode out many gales and one storm and were lucky enough to never drag. Storyline is a bit bigger at 36' and now we carry 70m of 3/8" but of that 20m is led aft and lives amidships . Very rarely deploy it but when we have done it has been very nice to have it available. If I knew then what I know now I would have gone for 8mm.
 
J Neeves said:
Because coral has an insatiable appetite for nylon! Rocky anchorages might be a bit less forgiving maybe 2 nights of safety vs one night for nylon in coral - but unless you only anchor in mud or sand (which many do) then never use an all nylon rode. It has nothing to with weight, or catenary - its all about abrasion. But even sandy anchorages have old concrete mooring blocks etc etc - its a compromise - be aware of the risks and you then can make your own informed decisions.

On the last but one Vendee Globe one of the competitors anchored at Auckland Island part of but way south of S Island NZ, its around 30 degrees south, for repairs. He used a Fortress FX 55 the rode was eaten through overnight - he then deployed his second FX 55. When he left he simply cut the rode (difficult to retrieve an anchor single handed in an Open 60).
Jonathan
Jonathan
Click to expand...



I am collating all the answers into an average. How much chain do you think the OP should carry in Scotland?
 
Then I can exclusively reveal two things:

1) I have too much time on my hands.

2) The average length of chain suggested is: 48 mts

The OP suggested, in post 18, that he was considering 40. So, as they say in the antipodes, happy days.
 
Ravi said:
I have a 30 ft. boat with 40m of chain and 20m of warp.

My friend has a 35' catamaran.
He had NO chain - just 60m warp. I spent years moaning to him about the terrible risk he was taking and hectoring him with the anchoring theory that we are all so aware of.
His response was that he had been sailing for 30 years and had never had an anchor drag. He is a very intrepid sailor who sails (and anchors) in the most unlikely places, so it was hard to argue with him.
A few years ago, just to shut me up, he put a couple of metres of chain on the anchor, (keeping the 60m of warp). Thankfully, we have had no dragging anchors, or I am sure he would have blamed the chain!
I am a disciple of the RYA and pile out my chain, as per RYA recommendations.

But, on his yacht, I have seen, for myself, that an all-warp scope can do the job, even in a ripping current in Jersey.

Maybe he is just lucky or maybe the importance of chain is overstated. Who knows?
Click to expand...

On my trimeringue I have 5m of chain and 50m of warp with a Fortress or Knox hanging off the end.
Never dragged.
After a blow it's getting the sodding thing out that can be a problem, especially the Fortress.
 
noelex said:
This is our Fortress holding us on temporary basis @ 4;1 in 5m of water on an all rope rode.

The anchor has set reasonably despite the absence of chain and reasonably modest scope. Look at the angle of the rode.

imagejpg1_zps599bbb30.jpg
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Aha! not all textile - do I not perceive 15 links of m10 chain?
 
charles_reed said:
Aha! not all textile - do I not perceive 15 links of m10 chain?
Click to expand...

No, that is just my lousy splicing.
It takes skill to make the splicing so lumpy that it looks like chain :)

I would normally recommend at least some chain. Chafe is always a real worry.

As others have said, catenary disappears just when you need better holding so rope rode holds almost as well, but the initial setting of the anchor (before you apply too much force) does benefit from a little catenary. As well, many of the modern anchors (NOT the Fortress) need to "fall over" to adopt the correct setting position. The weight of the chain helps make them less stable upright, especially when you only have a short scope with some vertical force keeping the shank sticking up.

Despite the above comments, anchors will still perform without any chain. This is particularly important with the Fortress that can be easily swum out with the aid of a small fender. Less, or no chain obviously makes this easier and as the photo shows the Fortress will usually set and hold without chain should the need arise.
 
Last edited:
Jonathan,

Thank you, thats is very informative explanation about your particular anchor and the way is sets, but, quite how, from your photograph with the rode at 30deg. it can bury itself further, and I am not disbelieving you when you say it does, just looks to me, and this is just my thoughts on it, like it is just as likely to come out at that angle than to bury deeper, taking the least line of resistance.
I use a CQR, they are either loved or loathed I know, but mine has served me amazingly well in many different bottom conditions, and is usually reluctant to be retrieved, only time I had to dive on it was on a rocky bottom. last spot in an anchorage, had wedged tight between two rocks, a large (Italian) fishing boat tugged it out for me using some heavy cable they had on board.
The videos of a CQR (developed I believe by the RN during or just after the war) shows is lays on its side, and as the chain pulls it it flips over and begins to dig in, with a good catenary buries the shaft also and some chain to, even when the chain is at an angle it stays buried. My technique is to drop the anchor plus 2 x depth before I begin to reverse with chain running until I have 4 x depth out, then stop the chain but continue slowly in reverse letting the anchor stop me, give it a few more revs to make sure. If calm thats it, if not give it another 1 x depth, check marks for 15/20 mins to further ensure all is well. Last job to fit my snubber.
I am in Greece, those there will know that many of the charters are those out for the first time, after their several failed attempts I have offered to be the bowman, using the technique described got them set in good order, and enjoyed the beer afterwards.
 
CQR anchor was invented by Geoffrey Ingram Taylor in or before 1933. YM published an article about its development in that year. Although Taylor was a renowned mathematician and a keen yachtsman the anchor was developed for flying boats, his practical research carried out in the Thames estuary.
 
Sarnia said:
Thank you, thats is very informative explanation about your particular anchor and the way is sets, but, quite how, from your photograph with the rode at 30deg. it can bury itself further, and I am not disbelieving you when you say it does, just looks to me, and this is just my thoughts on it, like it is just as likely to come out at that angle than to bury deeper, taking the least line of resistance.
Click to expand...

The shorter the scope and the higher the angle of pull from rode the less likely the anchor is to bury, which is why the holding does down.

However, it is quite amazing how a good anchor can still bury despite the angle of pull of the rode.

Here is some video I took of my Mantus anchor setting at 3:1 in 4.4,m (14 feet). The quality is not great after the youtube processing, but if you look closely you can see the high angle of the chain.


 
vyv_cox said:
CQR anchor was invented by Geoffrey Ingram Taylor in or before 1933. YM published an article about its development in that year. Although Taylor was a renowned mathematician and a keen yachtsman the anchor was developed for flying boats, his practical research carried out in the Thames estuary.
Click to expand...

Thank you for the correction and further interesting facts about the CQR origins.
 
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