1/4"HT vs. 5/16" Proof Chain

[Bash]

...I can't help but note the connection that the person who sells anchors wants us to believe that it's all about the anchors and that it has nothing to do with the chains.

Go with the 5/16".

[Benny]

OK Anchora - when you can mathematically calculate all the variable forces that may be in effect at all the variable time frames that occur to a vessel and it's ground tackle at every variable moment in a storm and factor in the state of that ground tackle, the vessel itself and it's crew to withstand those forces, then undeniably prove your theories, you may only then be able to possit your asserertions however, until then, and I suggest that you will not personally be remaining alive even if you spent the rest of your life trying to do those calculations, will this group of very experienced sailors consider your findings.

Your math may hold true with brand new equipment, boat, unchanging wind direction and force and unchanging wave height, force and duration. When you encounter these conditions in any gale or storm anywhere in the world, please let us know.

[Ancora Latina]

Originally Posted by Benny

. this group of very experienced sailors...

OK Randy,

But I believe I’m by far more experienced than this « group of very experienced sailors » both by the number of years of sailing, by the number of years of racing, by the number of years full time living aboard, by the number of nights spent at anchor, by the worse anchoring conditions encountered in the South of Latin America, by the number of anchor studies.. Etc...

And I do not consider that it is enough to ask you to not personally be remaining alive!

As I tell my grand kids often "don't slag something until you've tried it". Is that a relevant statement here?? I suspect it maybe.

By experience, I perfectly know that “new theories” are seldom accepted by “conservative” people, but they are these ”new theories” which make “progress”...

Yes, I will not remaining alive on this thread, because I perfectly know that it is IMPOSSIBLE to change the mind of “very experienced conservative people”

Regards

João

[starfish62]

I love engineers. My dad, uncle, father-in-law and cousins are all engineers. The systems involved with sailing are best resolved intuitively, rather than rationally.

[Northeaster]

Anchor Latina - I feel that others do have the right to disagree with you. However, I appreciate that you do, have both the math skills, and real world experience to give an useful opinion on the subject - and I, for one, appreciate hearing your views. Other can certainly give their veiws as well.

I will NOT hold your views against you, and would look forward to your posts in the future.

I don't believe that you suggested anywhere that having an appropriate amount of weight (in both chain and anchor) was not needed - just that having excess weight was not the be all, and end all.

[Benny]

Ancora - my post was not a suggestion to not remain alive - and you would know that if you read it - but that neither you nor I would be alive after the amount of time required to mathematically calculate every possible variable in any storm anchoring situation. If you have all the experience you claim, you will also know that relying solely on mathematical data to make possible live saving decisions is folly and it is always better to overcompensate to allow for possible mathematical rule breakers. Like nature.

And I don't believe it is impossible to change minds - conservative or otherwise - with tried and true data not just theoretical math. That is the experience I am speaking of which I am sure you can relate to having gained so much sailing experience yourself. All of us have had gear fail or situations develop that were thought to be mathematically or technically improbable. I know that I would not want to leave the safety of my crew or self to a pure math formula when common sense experience dictates caution. Prudent room for error on the side of caution will always be preferrable. This may demand a small compromise but is worth it.

My advice is to go with the heavier chain and if buying it now - go with 5/16 HT which is better than 5/16 BBB.

[Hiracer]

Without any resort to mathematics, I would argue that Joao is absolutely correct in so far he points out that the shock-absorbing effects of chain catenary provide the least benefit (to the point of being non-existent) at precisely when you need it the most. Therefore, to rely on catenary and eschew the elasticity of rode is ill advised unless you can always guarantee that you don't need the shock absorption. Of course, if you know you don't need much elasticity in your anchoring system, the entire subject becomes pretty moot and chafe becomes your chief concern--which doesn't auger for big chain sizes.

In other words, catenary's effectiveness as a substitute for line elasticity is inversely proportionate to the degree that it is needed. In the worst case scenario, the chain goes bar tight at the height of the blow and bad things start to happen to cleats, shackles, and/or underwater substrate adhesion (anchor dragging or letting go). Bar tight chain instantly translates to skyrockting shock loads.

Therefore, the thoughtful sailor will use chain solely to counter abrasion and chafe, and not as a substitute for line elasticity.

So, I agree with Joao.

Now, having said that, I much prefer full chain over chain/nylon combinations precisely for the chafe protection. But I would advise going with the lightest chain (up to HT but not the more brittle alloys) that you can use safely for maximun load purposes, because all reasonable chain sizes provided perfectly adequate chafe protection.

I fail to see any benefit from large chain sizes given that no matter how big you go it remains possible for nature to make that chain go bar tight. Given this truth, I always prefer nylon snubber (in my case 25' to 50') over chain catenary. It is a demonstrable fact of life that a long nylon snubber does not have the inverse proportionate shock absorbing characteristics that chain catenary does.

Further, a nylon snubber is cheap, easy to replace, and is light on the bow thus aiding sailing performance.

For those mathematically inclined, I would recommend Van Dorn's book, where he gets into how to compute chain/nyon combinations for specific depths and just general usage. He also summarizes in English, so you don't have to actually understand the math.
Oceanography and Seamanship by William G. Van Dorn

Van Dorn is a brilliant scientist a la Scripps, long-time sailor, and he also agrees with Joao.

[Hiracer]

P.S. Most modern designed sailboats swim or hunt at anchor in a blow. That motion is what will initiate the shock loads from a bar tight chain. Thus, the wind load needed for a bar tight chain may be less than what you think if you have a modern boat.

In any case, why adopt an anchoring system which to operate properly requires you to accurately predict the wind load night after night? I much prefer to gravitate to a bomb proof system, every night, regardless of my projection of wind load. That way I don't have to worry about my own fallibilty.

To say you will add additional elasticity on only those nights when chain catenary might be insufficient requires either (1) that you under all conditions remain a light sleeper or (2) always know what the weather will do. But line elasticity is a simple way of avoiding all that. It's easy, cheap, and always there no matter what.

You can't say that about chain catenary. Chain catenary is there basically when you need it the least.

[witzgall]

Interesting. The windlass I am considering, A Lewmar V1, will work with either 1/4 ht or 5/16 ht, depending on the Gypsy. A call to Lewmar confirmed that it will most likely jam with any other non HT chain, such as Proof Coil or BBB. We happen to have 100' of almost new 5/16 G3 chain. So I would need new chain. Since the bow compartment is very small, I don't think 200' of 5/16 anything would fit nicely in there, unless some were led through a pipe to the first compartment in the v-birth. I considered that , but I do not want the dampness or smell underneath the bunk if it can be at all avoided.

So I think that a 200' of 1/4 ht, the windlass, and perhaps a slightly larger or newer tech anchor, than the 35lb CQR, might be in order.

So now, do I put add another battery up in the bow, or go with my preference and just use the house bank, with a run of #2 cable to the windlass? The windlass is 700 watts.

Chris

[Ancora Latina]

Originally Posted by Hiracer

So, I agree with Joao.
Van Dorn is a brilliant scientist a la Scripps, long-time sailor, and he also agrees with Joao.

Thanks Hiracer...

João

[Hiracer]

Joao,

Thank Van Dorn. He's the one who educated just about everybody on subjects like this.

"According to Edmond L. Mandin, retired marine superintendent for American President Lines, Oceanography and Seamanship has a place in the master’s research library of every APL containership. “It is considered to be the primer for APL deck officers in the strategies of heavy weather seamanship.” This book is an outstanding resource for both the recreational sailor and those in the shipping business who would like to learn more about the behavior of the ocean and the response of the craft that ply it."
"Originally slanted toward cruising yachtsmen, the book has gained a solid reputation among commercial fishermen, charter boat operators, and shipping companies. It is a reference at maritime academies and is used as a textbook in colleges and secondary schools."
Oceanography and Seamanship

The second edition of the book is 1993. I can't find when the first edition came out, but I'm pretty sure it was pre-1979 Fastnet. Anybody know? I'm pretty sure Van Dorn is the godfather for most modern thinking on anchoring.

[Hiracer]

First edition 1974.
http://repositories.cdlib.org/cgi/vi...ntext=sio/arch

Page 17.

What an interesting man.

[thinwater]

Originally Posted by witzgall

Hi all;

I am been thinking abouut our ground tackle and systems. Currently there is no windlass onboard, just a big honkin' cleat. We have 100' of chain, which I think is 5/16 proof coil.

It should be secured with some sort of chain hook. The pictures are for a 2-leg bridle. A regular chain hook on a length of line will work as well - enough to snub the wave impacts.

A windlass is not, in general, designed to hold the load.

[thinwater]

11111

[Cheechako]

Just keep in mind in a shallow locker that as the chain comes in, it will stack in a pillar under the chain pipe. When the pillar reaches the chain pipe, the windlass will jam. To avoid this you will need one person to push the pillar over as it stacks up. It's absolutlely amazing how vertical and small diameter (?)the pillar can be.