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Chain anchor rode length

8K views 20 replies 11 participants last post by  Craig Smith  
#1 ·
We are within a year of begining our circumnavgation. Most of the systems on our old Ericson 35 have been rebuilt/replaced, the latest being the addition of a Maxwell windlass. The next step is the purchase of 5/16 hi-test anchor chain. The question: HOW MUCH?? Our anchoring ground will vary from leaving Southern California, to the standard stops on an around the world trip of ten years (the wildest current guess). From what I've been able to read and gather, anchoring in up to 80' may be inevitable. A half keg of chain is 270' (what I have now, just some oddball size that doesn't seem to match anything else manufactured in the world). Along with 250' of octabraid on the main, I'm hoping that will be sufficient. The old chain will be used for the stern anchor (at least the 200' that is still not too corroded). Any advice from those that have been?
 
#5 ·
Check our Earl Hinz's book The Complete Book of Anchoring and Mooring. It's the most complete book on the subject that I know of and will answer your questions. The only area where I had to find other info was my anchoring cleats (I don't use a windlass). I found that I needed to look at the bolts holding it down and thier shear streingth compared to the load. It turns out that SS bolts are a lot weaker in shear than you might think. I ended up putting in more/larger bolts with a big backing plate.
 
#6 ·
You will likely have to ride out some weather at anchor at some point and there really is no substitute for all chain at that point with a good snubber. When it gets really bad, the chafe resistance of the chain becomes crucial because even a good snubber can fail. I would think that you would want the ability to anchor on all chain with good scope in all reasonable depths(up to 50'). So a half keg with some additional heavy rope rode would be my choice, the additional rode for when it is super deep.

As far as putting 200' of chain on your stern anchor, that will make it very hard to use. It sounds like the chain won't fit your windlass and that would me re-leading it forwards anyways. Much more than 50' or so and it will become unmanageable. If you have the choice, storing this closer to the centerline of the boat would good. Up to a reasonable point, weight on a boat isn't too bad but the issue is having it in the ends because your inertia will increase which will put the boat out of phase with the waves. In extreme cases, poorly loaded boats pitch wildly. Since you have already been carrying the weight of the primary anchor and chain forwards and haven't had problems, I wouldn't worry about it but it is a considering when packing.
 
#7 · (Edited)
I'm butting in here , not being one of those who has done it all, but.....

The occasions when you will anchor in 80+' are going to be rare.

Most times I would have thought 150' of chain would be ample with the rope for when you need to get all the chain on the bottom. Even 150' is not light weight living up front. What's the Ericsons anchor locker layout ?

If you then find the occasion to need an extra 100' of chain why not keep that separate from the other, stowed way down low and only brought out when needed. Yes it's a bore when you have to do it but keeping the weight down in the ends, is important.

I've never heard of anyone using chain (other than the first few metres) for a stern anchor. Maybe I'm wrong but I cannot see the need for it.

We currently carry 120' of chain and have found that sufficient for all our needs but have never anchored in deeper that 60'. Then I put all 120' on the bottom plus rope. We are 34' steel. displacement 5.4t (12,000 lbs).
 
#9 ·
I'm not entirely sure how to interpret "the standard stops on an around the world trip of ten years", as ten years is more than enough time to make some considerable detours from the 'usual milk run'. That said, deep water is probably unavoidable as a lot of it is in your way across the Pacific.

Chain length required depends almost entirely on this, so discount any thoughts of catenary, helping the anchor, and other misconceptions.

On Kiwi Roa, the two main anchor rodes are 100 and 50 meters chain respectively, plus 50 and 100 meters respectively of 8-plait polyester. "From those that have been", this is more than adequate.

The main reason I am responding is to suggest you reconsider your choice of 5/16" hi-test. We would go with 1/4" high tensile G70, which saves about 35 lb per 100' of length and is still stronger. (Well actually out of the US and given an international cruising area we would be going with metric sizing but that's beside the point). There is no need to carry the extra weight of medium-lower tensile grades.
 
#15 ·
On Kiwi Roa, the two main anchor rodes are 100 and 50 meters chain respectively, plus 50 and 100 meters respectively of 8-plait polyester. "From those that have been", this is more than adequate.
Craig,
Are you saying that when you laid a stern anchor you had up to 50 metres of chain on it ? I honestly didn't think that one needed more than a short length of chain (of course plus line) out the back. Interesting.
Regards
 
#10 ·
Many thanks for the great feedback. I'm really appreciating the comments on the stern anchor chain length, as that will not be in use very often (when you have it sitting at the dockbox, it's hard to let it go...). The primary is easy to justify. The reason for the 5/16" is the windlass just installed is set up for it. I like the idea of keeping the weight more midships... will work for the stern anchor and associated rode. I'll ck out the Complete Book of Anchoring. Thanks for the tip. Our "milk run" plan includes plenty of time for messing about and hopefully never having to get in a hurry to be at any place at any time other than weather and current considerations. I've been told if you can anchor in Southern California you can anchor anywhere, but being old and grey and a bit cautious...
Craig, your Rocna anchor is next on the list when the rode is bought, so I do appreciate your real world experience. Given a choice between a SS plow and a SS danforth copy (because I inherited both with the boat), which would you take as a stern/backup anchor?
 
#11 ·
Neither, without more info, on account of the risks of poor quality stainless steel. As to the type, a Danforth is more useful as a stern anchor. They're no good as primaries but if they're not subjected to veering loads they represent efficient and easy-to-stow holding power. Sell them both to a marina sailor who likes shiny things, and get a genuine high tensile Danforth or Fortress, or, preferably, something like an alloy Spade.

As to the chain, investigate the cost of swapping the windlass gypsy, the weight savings will be worth it.
 
#12 ·
First, I wouldn't go with that much chain. Chain adds too much weight forward and will increase the boat's tendency to hobby-horse and to bury the bow. At most you will probably want 100' or 150' of chain. More than that really isn't all that useful for several reason IMHO.

A) It adds a lot of weight forward.

B) The primary advantage of chain over nylon is chafe resistance, and in deeper anchorages, coral, one of the primary causes of chafe, won't exist.

C) A combination rode generally offers better anchoring performance than all chain.

Second, I wouldn't go with either a danforth or plow anchor as a primary. While a Danforth or Fortress makes a great stern anchor, they're not ideal for a primary anchor, since they don't deal well with reversing winds/current situations, and in a circumnavigation, you'll probably find yourself in a lot of anchorages that suffer from one or the other.

A next generation anchor, like the Rocna or Manson Supreme will have more surface area than an older plow design and set better and reset better than a Danforth or fluke-type anchor. They are also far less likely to jam, which a Danforth can do and that can prevent it from resetting.

Third, I also wouldn't recommend a stainless steel anchor as a primary for several reasons:

1) Stainless steel is much weaker than steel is for the weight unless you're dealing with very expensive, special purpose alloys of stainless steel

2) Stainless steel suffers from crevice corrosion and after enough can fail with little or no warning—whereas galvanized anchors will generally give you a lot of warning and a long time to remedy the situation

3) Stainless steel anchors are far more expensive than galvanized steel anchors and you can often buy several excellent galvanized steel anchors for the price of a single mediocre stainless steel anchor.
 
#13 ·
I had not considered that in 'extra deep' anchorages coral (and therefor chafe) may not be the issue it is in more normal situations. The comments on stainless steels are appreciated. I'm leaning toward the danforth for the stern & Rocna on primary. If I put 'only' 270' chain on the main with a 250' 8braid It sounds like this will be sufficient. I still question the stern, only because I have chain already and have a place low midship to store it. An extra 200# ballast won't hurt, although it is not instantly available for use. I've sailed the boat for 5 years now with the weight in the bow, and it behaves well, maybe due to the long overhangs inherant in a 40+ year old design. Many thanks for the insightful comments from all.
 
#16 ·
TDW no that is a secondary bow rode, the third rode which would be used for a stern anchor is 30 m chain + 100 m 8-plait rode shackled. Fourth rode is 15 m chain, plus a selection of 100 m rodes, and other bits and pieces. It's all the same size matched to both windlasses' gypsies.

We very very rarely use a second anchor, including the stern anchor. We simply don't find it necessary. This Rocna, which replaced the old stern pick, has been here since leaving New Zealand several years ago, and despite all that time spent in Chile, Patagonia, and Antarctica, it's still unused :)

Image
 
#17 ·
TDW no that is a secondary bow rode, the third rode which would be used for a stern anchor is 30 m chain + 100 m 8-plait rode shackled. Fourth rode is 15 m chain, plus a selection of 100 m rodes, and other bits and pieces. It's all the same size matched to both windlasses' gypsies.

We very very rarely use a second anchor, including the stern anchor. We simply don't find it necessary. This Rocna, which replaced the old stern pick, has been here since leaving New Zealand several years ago, and despite all that time spent in Chile, Patagonia, and Antarctica, it's still unused :)
Craig,

I'm beginning to fear you might have an anchor fetish..... or is it just that you into a bit of BDSM ? All this talk of chains and shackles.....:)

Cheers

TD
 
#18 ·
Ericson 35

This thread caught our eye not because of the anchoring theme, but because we have a 1976 Ericson 35. We carry a 45 pound CQR with about 70 feet of chain and intend to increase that amount plus a 22 pound delta lunch hook with the same amount of chain. That's done well in Gulf waters (Keys, Mississippi Sound, intracoastal waterways, Georgia, Carolina). Off topic: we'd be interested to follow your adventures once they start. We just hauled out for 6 months worth of projects and hope to begin some similar adventures soon enough. We've only had our Ericson 2 years, but will be happy to share any tidbits you might find helpful, either through the forum or private messages. Best of luck!!
 
#19 ·
If 60 feet is as deep as you might be expected to anchor, a scope of 3 to 1 is 180 feet of chain out. 3 to 1 is really no good if there is any kind of serious weather or big seas are hitting your anchorage. 60 feet deep at 6 to 1 is 360 feet of chain. If you are anchored in a bad storm there is a real danger of chafe on rope. You will feel a lot better with chain at the chafe points, or at what will be the chafe points if your anchor bridle lets go. If you are going cruising plan for riding out some major storms on your anchor, and accept the burden of the extra weight of an abundance of chain. I don't think you need much chain for your stern anchor.
 
#20 ·
On the other hand, contrary to my own views, Don Dodds' book "Modern Seamanship, a Comprehensive, Ready Reference Guide" makes a good argument, starting at page 171, for using mostly nylon rode, with only half the boat's length or so of chain. Dodd argues that the elasticity of nylon is more important than the abrasion resistance of chain, using only enough chain to deal with coral, rocks and to give some weight around the anchor.

He argues, correctly, that in enough wind or big enough waves the chain may lose its catenary and get straightened out. Since it has no give, tremendous momentary and damaging shock loads may result.

He deals with nylon abrasion at the bow by suggesting putting plastic hose around the line where it goes through chocks or at cleats, and, though he doesn't say so, going back up to the bow several or more times a day and night to replace the chafing gear. Hopefully, without hurting yourself.

Maybe there isn't a best answer, maybe it is a personal choice about which advantages and drawbacks each person choses.

Can somebody comment on whether, as your boat length and weight increases, the weight of the chain you are carrying becomes less important? My guess is that 300 feet of chain in a 30 boat is more of a problem than the same amount in a 45 boat, even with thicker chain for the bigger boat.

As an aside, I found the Dodds book online at Google books and read his section on anchoring there. Very cool.

Ian
 
#21 ·
Yes it becomes less important on larger boats, obviously the length required cannot scale down with a smaller LOA, which is why using high tensile grades to attain the require strength for less weight is a good idea.

Don Dodd is 100% correct with regard to an anchor rode in normal circumstances. Heavy chain is entirely pointless with regard to "helping the anchor", and a shock absorber is important. However, on a world cruise, depending on the destinations, "...the elasticity of nylon is more important than the abrasion resistance of chain, using only enough chain to deal with coral, rocks..." will give you lengths similar to those discussed above. Deep water anchorages with high coral heads in the Pacific or steep rocky cliff-side drop-offs in Antarctica require a lot of length to avoid rope ending up on something sharp. On the other hand if you are day sailing in Maine, Don's advice is exactly pertinent.

If you have those "all destinations" chain lengths, then you end up using a 100% chain rode (chain never leaves the gypsy) by default in the majority of anchorages. That then mandates the use of a snubber, nylon or otherwise, as a shock absorber; always on smaller boats, and sometimes on larger ones. A more minor factor is also the convenience of the chain not leaving the gypsy, again more of an issue on a larger boat, and the extra layer of security that brings (should the nylon chafe or otherwise fail).