Choosing the most fail - safe anchor chain

[PanPan]

Originally Posted by DoubleWhisky

Looking at Your chain I'm already jealous of Your BOAT ! ! !

No boat yet. Figured I'd get into sailing from the ground up.

[IdoraKeeper]

No snubber = wear and tear on the dog on your windlass and the gypsy. I have awakened to find the snubber stretched 2 meters after an active night of the chain bounding and yanking. Just sayin.

[DoubleWhisky]

Putting the snubber discussion aside (as it is not real matter of this thread) I think that determining what anchor chain material offers the most security (best compromise of resistance to static and dynamic loads) can be really useful.
Chain made of such a material can give us most security for given weight, or the opportunity to use the lightest chain for desired level of security.
May be it is completely wrong thinking, I'm not an engineer...
Still I hope for disscussion of it by knowledgeable members of the CF, like Andrew Troup, estarzinger, JonJo, Pauls, Dale Hedtke and many others with deep experience regarding the real world applications of different kinds of steel.

[Adventurebound]

I don't know if it has ever been mentioned, but in my research rust is one of the biggest factors in deciding chain weight. You want lots of "meat" that can rust away before the chain is useless-after about 5 yrs heavy use.

[Nicholson58]

We have 320 feet of 7/16 G3 on the primary and 400 feet of 1" secondary. All total, I estimate about 1 ton of chain, anchors, windlass on the bow. It would be nice to run the chain aft & place a hawse pipe in front of the mast with central chain locker. I don't think the admiral would appreciate losing part of the guest cabin.

[Scott Berg]

A few comments...

In 50 years of sailing I've never seen a chain break;
Shackle, yes
Swivel, too often
Windlass clutch do to poor snubber, check
Chain, not yet. We have 276' of 7/16 primary and 80' secondary to 250' of 3/4" 8 plait
110# Real Bruce
Sleep well ;-)

[Dockhead]

Originally Posted by Nicholson58

We have 320 feet of 7/16 G3 on the primary and 400 feet of 1" secondary. All total, I estimate about 1 ton of chain, anchors, windlass on the bow. It would be nice to run the chain aft & place a hawse pipe in front of the mast with central chain locker. I don't think the admiral would appreciate losing part of the guest cabin.

400' of 1" secondary? Surely that's a typo. 400' of 1" chain weighs about 2 tons.

If I were you, I would ditch the second chain rode (whatever size it is). I thought my situation was bad with 400kg of ground tackle in the bow, but one ton? That's crazy. Rope is the right thing for secondary rode, IMHO.

[kentobin]

Catenary & Scope In Anchor Rode: Anchor Systems For Small Boats

Among the conclusions of this article:
"The catenary from the chain is often assumed to be a good shock absorber, in addition to lowering the angle of pull on the anchor, as it takes some time to straighten. However, this is a fallacy, as this quasi “spring” disappears in bad conditions when it is most needed. A proper shock absorber is a nylon snubber or similar."

[Nicholson58]

Originally Posted by Dockhead

400' of 1" secondary? Surely that's a typo. 400' of 1" chain weighs about 2 tons.

If I were you, I would ditch the second chain rode (whatever size it is). I thought my situation was bad with 400kg of ground tackle in the bow, but one ton? That's crazy. Rope is the right thing for secondary rode, IMHO.

400 feet of 1" secondary is 3-strand - note the photo.

[sparrowhawk1]

Originally Posted by Nicholson58

400 feet of 1" secondary is 3-strand - note the photo.

It looks like you have 5 links of heavy chain in between the anchor and your standard chain just curious what's the purpose of that?

[Cheechako]

As you indicate, often any of 2 or 3 choices will work just fine. The matter is mostly up to what your windlass can use and how much storage you have.
I have often wondered about chain quality... so... modern quality standards pretty much all require above a 99% no defect rate. Let's think about that.... how long is 100 links of chain? Maybe 12Ft? So a supplier with a 99%+ no defect rate still could have a one defective link in every 12ft.! 99.5%? what is that.. a defect in 24 ft of chain? I know... not a direct analogy, but ...hmmm....you get the picture...

[DoubleWhisky]

Originally Posted by Cheechako

As you indicate, often any of 2 or 3 choices will work just fine. The matter is mostly up to what your windlass can use and how much storage you have.
I have often wondered about chain quality... so... modern quality standards pretty much all require above a 99% no defect rate. Let's think about that.... how long is 100 links of chain? Maybe 12Ft? So a supplier with a 99%+ no defect rate still could have a one defective link in every 12ft.! 99.5%? what is that.. a defect in 24 ft of chain? I know... not a direct analogy, but ...hmmm....you get the picture...

The same thing occured to me... I have some 320 feet of anchor chain. 2500 links? 3000?
With this we need really defectless product. Happily making chain is not a rocket science, so we were on the safe side for a long time. But now, with tendency to push up the envelope and going for lighter and lighter chains it is not bad to know, what material offer the biggest safety margin all around (including the possibility of welding breakage).
I really hoped for a deep in disscussion involving people with real technical (engineering) background and/or interest. But starting such a disscussion without gus like, for example, Andrew Troup and JonJo contributing, with their deep involvement and detective attitude, will be really difficult. It is a pity they both are absent from a forum for some three or four days now...
Anyway, let's hope for some real engineering input here...

[Cheechako]

Originally Posted by kentobin

Catenary & Scope In Anchor Rode: Anchor Systems For Small Boats

Among the conclusions of this article:
"The catenary from the chain is often assumed to be a good shock absorber, in addition to lowering the angle of pull on the anchor, as it takes some time to straighten. However, this is a fallacy, as this quasi “spring” disappears in bad conditions when it is most needed. A proper shock absorber is a nylon snubber or similar."

Seas are the issue more so than wind (sure they can be related, but not all the time)
I have snorkeled my 42 cat anchor in 35 steady knots of wind. The chain still had catenary. We were very protected with virtually no fetch so maybe 6" chop at most!
OTOH, I have been in 20+ knots of wind with waves coming in the anchorage of 2-4 ft. The chain kept snubbing up hard and bar tight as I tried to get the anchor in to get the heck out of there!

Thinking out loud here... I guess if my boat could use say.. 5/16 hi test or 3/8 BBB, I would want the one that was the toughest and had the best elasticity, over one that was theoretically slightly stronger ... negating the weight factor of course. The BBB might rust less too, what the effect of slight rusting on one link is I don't know.

[Blue Crab]

DW, was there something about chain that was left out of this discussion: http://www.cruisersforum.com/forums/...ain+elasticity ?

[DoubleWhisky]

Originally Posted by Blue Crab

DW, was there something about chain that was left out of this discussion: http://www.cruisersforum.com/forums/...ain+elasticity ?

I think so.
The BiB 2 thred led to the "near conclusion" that high tensile steel give the chain possibility to accomodate much greater static load, but at the price of greater probability of catastrophical failure under dynamic load, especially repeatitive dynamic loads.

This thread I opened to look for answer not to the question, how make a lighter chain possible, but to look for answer to the question what material offer best compromise regarding both static and dynamic loads.

By the way - I wrote the "near conclusion" as at the peak moment of the discussion two main participants somehow disappeared from the thread (now I think from board at all, leaving the topic unfinished. Before opening the new thread I contacted Andrew Troup via PM, and it was also his opinion that separating this two similar but not identical topics will help to have a clear picture... But he is missing for some days, as well as Jonathan...