Nylon vs Polyester

[craigsmith]

Minggat any "advice to go all chain" you hear from others is probably a bit off - such a decision is highly specific to a boat and its crew. There is no universal rule, no performance advantage to all chain. It's just convenience for the most part.

Kiwi Roa has 100 m of 12 mm chain, plus rather long lengths of polyester tail. This length of chain has precisely nothing to do with shock absorption or anchor performance.

I could elaborate but I guess you're off-topic.

[Rick]

Even with a nylone/chain rode always use a snubber which is sacrificial in addition to allowing more stretch. The key to snubber longevity is to use double-braid polyester from the vessel's attachment point to outboard of the last fairlead and then use nylon for the rest of the snubber. I used to wear out several snubbers until getting smart in the use of Dacron-polyester to prevent chafe at the boat.

You can always attach a backup snubber in case the first fails. When a snubber fails in a heavy surge and wind it sounds like a rifle shot down below. You can hear it everywhere.

I have made many dives when visibility permitted on my boat and other boats at anchor in heavy sea and wind conditions. When the wind is heavy all boats sail at anchor at least somewhat. The chain drags over the bottom in an included angle due to the sailing. IF the chain lifts out (from the effects of wind and waves) of being buried on the bottom up to the attachment at the anchor the boat is in immenent danger of dragging and one needs more chain or a sentinel weight. Once the chain leaves the bottom at the minimum effects of wind then it is good to have nylon from there up. I now use double braid polyester from the end of the chain for at least 20 feet thence convert to nylon. I never use nylon double braid because it is too expensive, does not stretch as well as 3-strand or brait, and is a bitch to splice compared to polyester.

Use a Prussic hitch to attach the nylon part of the snubber to the rode, even at the chain. It is much more reliable than a chain hook or other device.

[Minggat]

Good input. Thanks.

[barnakiel]

Originally Posted by Unicorn Dreams

I think you will find that the chain and swivels etc. are the weak points in strength, 3/8" cgain is only 5400 lb. working load, swivels and shackles about the same.

There was a YM test on that:

- swivels went first,
- then the shackles,
- then the chains.

We do not use swivels. One weak link is good enough. ;-)

b.

[craigsmith]

Originally Posted by Rick

IF the chain lifts out (from the effects of wind and waves) of being buried on the bottom up to the attachment at the anchor the boat is in immenent danger of dragging and one needs more chain or a sentinel weight.

Oh nonsense.

Originally Posted by barnakiel

There was a YM test on that:

- swivels went first,
- then the shackles,
- then the chains.

We do not use swivels. One weak link is good enough. ;-)

Also nonsense. Be specific.

[cfarrar]

IF the chain lifts out (from the effects of wind and waves) of being buried on the bottom up to the attachment at the anchor the boat is in immenent danger of dragging.

By this logic you should anchor with lots of really heavy chain and leave the anchor at home! No, you need to assume that the anchor rode will be lifted off the seafloor and nearly bar taught. Therefore, it's scope that largely determines the anchor's performance, whether using chain, nylon, or poly.

[Minggat]

Originally Posted by craigsmith

........ no performance advantage to all chain. It's just convenience for the most part.

Craigsmith,

If you want to label other opinions here as "nonsense", then bear in mind that your own words may not be so carefully chosen. Could cost you some credibility.

Perhaps I depicted myself as a newbie when I took someone elses advice on anchoring 1,500 miles from my old cruising grounds. However I depicted myself, it is not a good idea to try and promote your own ideas by belittleing the opinions of others.... IMHO....

[craigsmith]

I don't know what your problem with your quoted text is. If you don't want the advice then feel free to ignore it. For my part, if people make public statements as if they're facts, that are clearly wrong on any objective basis, I am going to say so for the benefit of anyone who's interested.

[Minggat]

Originally Posted by cfarrar

No, you need to assume that the anchor rode will be lifted off the seafloor and nearly bar taught. Therefore, it's scope that largely determines the anchor's performance, whether using chain, nylon, or poly.

Well put. I got the same meaning from Ricks posts. Using the word scope give things a different clarity.

But with chain (weight), as long as it IS (mostly) on the bottom, the pull will increase the effectiveness of the scope. Don't know if that comes out right, but looks good to me.

I can see this going into a bunch of people saying the same thing using different words and not knowing how much they agree.

Having said that, I have to say that I agree. Best to assume that the anchor rode will be lifted off of the bottom.

[Minggat]

Originally Posted by craigsmith

..... If you don't want the advice then feel free to ignore it.

.... I am going to say so for the benefit of anyone who's interested.

Feel free to ignore this.

"Your statement is unclear when you consider..." vs "nonesense".

Do you wanna step on toes, or convince someone of your position?

Let's talk about Nylon/Poly line. I am quilty of starting the drift. Sorry folks.

[downunder]

in that the drift has been about anchoring I would say good drift

[craigsmith]

Originally Posted by Minggat

Feel free to ignore this.

"Your statement is unclear when you consider..." vs "nonesense".

Do you wanna step on toes, or convince someone of your position?

I want to get to the facts. The statement was not "unclear", it was utterly wrong and misleading.
I have no interest in either stepping on toes or appeasing feelings. It doesn't enter into the debate. You should perhaps rather feel a little insulted when someone tells you with a straight face than 2 and 2 is 5, not when somebody corrects them with I admit a little abruptness.

[CarinaPDX]

Since we are a little off topic here, let me take the opportunity to recommend a web page which is an interesting analysis of anchoring forces and anchor rodes. It has been awhile since I read it but IIRC the result is a recommendation of a mixed rode. In a sense all good rodes are mixtures of chain and rope, whether it is all chain and a snubber or 30ft of chain and the rest rope - we are basically discussing the ratio...

Site: http://alain.fraysse.free.fr/sail/rode/rode.htm

[Rick]

I was not clear about the chain lifting off of the bottom. My point is that when ALL of the rode lifts off of the bottom right up to the anchor attachment point then any further pull will endeavor to lever the anchor out. I have watched this on several different boats when diving and observing under heavy conditions.

With at least a few feet of chain still in contact with the bottom if the boat sails significantly then the anchor stock may work back and forth over the angle included by the chain moving over or through the bottom. The anchor may not pull out yet, again, if ALL of the chain lifts up you are in potential trouble.

What is often neglected in all of anchoring discussions is the effect of the boat sailing along with the up/down action caused by the waves. This is why static load test results should be taken with a grain of sea-salt.

[downunder]

Rick,

my observations are similar.