Chain Versus Rope Scope ?

[klem]

Many of the comments on this thread are related to chafe which was not the original question in the thread. I don't think that anyone on here will argue about this and I would hope that all of us would want as chafe resistant an option as possible. Unfortunately, there are compromises to be made and in many parts of the world, an acceptable compromise is a nylon rode instead of chain and a good snubber.

For the people that still don't agree that with reasonable scope chain will not increase holding power over line, I propose that we should do a scientific test to prove it. If anyone has a force cell, a videocamera, and an anchor that will set reliably with ~1000 lbs of holding power (something like a manson supreme 15) in the greater Boston area, I can provide everything else to do the test. I have a truck that has a secure point ~9' off the ground where we could attach a ~60' rode. We could do the test with all chain, a combination rode and all line and do several trials of each. Anyone have the equipment and want to help me out?

[Sailmonkey]

I have a chain/rode for use when docktied and anchoring a few weekends a year. For full time cruising I have the 250' chain with 250' rode.
I will freely admit the boat is happier without all the weight in the bow, but having been in several anchorage where there is no wind, clear water and lots of "rock" clusters on the bottom I am glad to have the chafe resistant chain laying on the bottom rather than the nylon. I have tried both and for full time cruising, chain wins hands down(with appropriate stoppers, snubber and backup snubber, and appropriate windlass). For weekends or even cruising a known area of soft mud bottoms, the nylon or other synthetic argument wins.
Data be dammed, this is a personal choice many people face. I know I am happier when I can see the chain wrapped around a rock rather than nylon.

[wolfenzee]

The answer to chain vs rode is not one is good and the other is bad...either one done properly is good, chain works best with nylon bridle and rode works best with about 25' of chain an a wieght rideing part way down the rode (called a "sentinal")...I have seen alot of boats on the beach after a good blow that had the recomned size anchor, tied directly to rode.
Properly done both are good and except for the chalfe issue ( and neglagence of other boaters) I would trust my boat/life to either.

[Sailmonkey]

But also as Klem says, the chain will not increase the holding power of the anchor.....it will as a function of it's weight act as an anchor until it pulls on the anchor with the appropriate wind.
There is actually a benefit of nylon setting the anchor more completely over time as the pull is almost always on the anchor rather than on the pile of chain on the seabed.

[wolfenzee]

Originally Posted by Sailmonkey

But also as Klem says, the chain will not increase the holding power of the anchor.....it will as a function of it's weight act as an anchor until it pulls on the anchor with the appropriate wind.
There is actually a benefit of nylon setting the anchor more completely over time as the pull is almost always on the anchor rather than on the pile of chain on the seabed.

The function of the chain is to pull at an angle closer to parellel to the bottom.

[conachair]

Originally Posted by JoeFish

The article is about catenary, not anchor choice. You don't need any degree to work that out, just basic reading comprehension.

His conclusions are, and remain agnostic when it comes to anchor choice. The only assumption was that the anchor itself was set properly and sized appropriately.

Actually Joe, I think they do have a bit of a point. Peter's article is pretty simplistic and barely even mentions the dynamic effects which happen in the real world.

Much more interesting stuff here - Rode - Dynamic Behavior Though the end result is the same. Lots force the catenery is off the bottom.

So assuming Alain knows what he is talking about, all chain is bad, big loads in the gusts, but put in 10m of nylon and the loads decrease dramatically. And which figures are relevant to not having your boat drag? Instinctively tension & angle of the rode above the sea bed. Complicated stuff.
And thats before even venturing into the physiological side of things

[downunder]

Originally Posted by JoeFish

Well, perhaps I am from the school of cruisers who both race and cruise and sail more than I sit in an anchorage.

I do however anchor about 60-70 times a year, just not for weeks or months on end. That's probably where a difference in anchoring philosophies can be justified.

Because I'd rather sail than sit in an anchorage I'd prefer my boat sail well. Perhaps it's simply a matter of asking yourself where the compromise lies for you as a sailor.

So the best advise in the real world that you give a newby heading to the carrabiean or pacific would be.

Slightly oversized, new generation, all chain rode.


For racing and with the experience you have in your area then you will be OK

For whidespread cruising I prefer and suggest all chain.

[conachair]

And another thing!!

These threads always go on so long because so many people have a deep belief that there is an answer!

[psneeld]

Originally Posted by conachair

And another thing!!

These threads always go on so long because so many people have a deep belief that there is an answer!

Yeah...but those that have the pin that says "been there, done that" have the luxury and sitting back and make fun of the OBVIUOS armchair seamen...

[Sailmonkey]

Originally Posted by wolfenzee

The function of the chain is to pull at an angle closer to parellel to the bottom.

Only until such a point that the caternary disappears.,....and it always will at some point depending on wind strength. Although for most purposes it'll always be there.

[JoeFish]

Originally Posted by Sailmonkey

Only until such a point that the caternary disappears.,....and it always will at some point depending on wind strength. Although for most purposes it'll always be there.

You'd be surprised how fast it goes away. The Boston test should make that very clear to those paying attention.

[RabidRabbit]

So just what is the disagreement here again? Some people who use chain refuse to beleive that its weight does nothing to hold boat in a big blow. And the rope guys tend to carry smallish anchors? Can I sum it up by saying even the largest chain (1/2") needs a huge anchor just like the rope folks, cause once the wind is 35-40 kts the chain is stretched, and might as well be rope. (except for anti chafe). All the talk of recommended anchors, who's recommendation are we talkin about!!! Use a big,big anchor if you wanna sleep. Not what some mag or anchor manufacturer says. It should be so big, that non cruiseing sailors think your nuts.

[JoeFish]

Originally Posted by RabidRabbit

So just what is the disagreement here again? Some people who use chain refuse to beleive that its weight does nothing to hold boat in a big blow. And the rope guys tend to carry smallish anchors? Can I sum it up by saying even the largest chain (1/2") needs a huge anchor just like the rope folks, cause once the wind is 35-40 kts the chain is stretched, and might as well be rope. (except for anti chafe). All the talk of recommended anchors, who's recommendation are we talkin about!!! Use a big,big anchor if you wanna sleep. Not what some mag or anchor manufacturer says. It should be so big, that non cruiseing sailors think your nuts.

Ha! That's it!

Actually us mixed rode guys (at least me) have anchors that are larger than most would advise. My Bruce is 20# heaver than the marketing materials call for and it's not a problem getting it up so I don't mind the added weight in the cockpit locker under way.

I think the argument here is that some of us prefer mixed rode over all chain and there are those out there that think we're going to drag into them because of it.

Strangely in over 100,000 miles of sailing, a few ocean crossings and countless nights at anchor I've never been the one to drag across a harbor (touch wood), and I've seen plenty of boats anchored with all chain rodes and inadequate anchors on the beach in the Caribbean. Go figure.

Bottom line, use a properly sized quality anchor. That's rule #1.

[Jim Cate]

G'Day all,

I swore that I would never get involved with an anchoring thread again, but I'm weak in my resolve...

Seems that we mostly agree that:

1. In extreme conditions one can remove the catenary from both chain and composite rodes,

2. That excessive weight in the bow has bad effects on sailing performance, but in different degrees for different boat designs.

3. That some means of reducing shock loading to anchor and deck hardware is necessary.

4. That for a given total weight, adding weight to the anchor increases ultimate holding power more than adding weight to the rode, and that some anchor designs hold better than others.

5. That many anchorages do not allow the use of large (7-10:1) scope ratios due to crowding or other size limitations.

6. That many anchorages have bottom features that can abrade or cut rope rodes, and that they may be unavoidable in practice.

Possibly I have missed some points of agreement, but these will do for now.

I add some personal observations, garnered from 25 years of continual cruising with ~90% of that time spent at anchor (as opposed to on moorings or in marinas).

1. I have personal knowledge of 4 boats whose rope rode parted due to chafe, and this parting lead to the loss of 2 of them. In one case the chafe was due to the nylon becoming wrapped around the boat's own keel in a wind against tide situation.

2. I have personal knowledge of 2 boats whose chain parted, resulting in the loss of the boats. One of these involved chain purchased second-hand from a Mexican fisherman who had condemned the chain due to excessive rust (WTF?). The other was a 72 foot ferro brigantine that was anchored on 1/2 inch chain with no snubber... during cyclone Lisa at Raoul Island in the Kermadecs.

3. In the cruising grounds that we have enjoyed (Pacific Ocean, Tasman, Southern Ocean) the all-chain rodes far, far outnumber the composite rodes once one gets away from day-sailor radius of yachting centers. Thus, the populations that lead to the above losses were heavily skewed towards chain.

4. That in less than extreme conditions, having chain lying on the bottom does reduce the magnitude of sailing about one's anchor.

5. That having an excessively stretchy rode or snubber causes "slingshotting" forward in lulls in the wind, allowing the boat to fall off beam-to-wind in the next puff.

6. That some hull designs bear the additional weight forwards better than others. For instance, boats with long overhangs and lots of rocker in the hull profile pitch more than ones with short or no overhangs and flatter hull profiles, and suffer greater detriments from added weight in the ends. As it happens, we made just such a design change between Insatiable I, an older IOR one-tonner and Insatiable II, a more modern hull shape with a dinghy-like profile and virtually no overhangs. The difference in pitching is remarkable... and both boats carry lots of 10 mm chain all the way forwards.

From all the above, I draw the following conclusions:

1. The security of all-chain coupled with snubbers of appropriate elasticity and length is better than a composite rode of equal strength. The ultimate holding power is essentially equal if similar anchors are used.

2. That all-chain rode is better adapted to the realities of modern cruising which entails crowded anchorages.

3. That for me the decrement in theoretical performance at sea is well offset by the advantages that chain offers. For others, whose boats may not bear the weight as well, the offset may not exist.

Finally, to answer the query about what gear is appropriate for South Pacific anchoring with a 35 foot boat: Insatiable I was 36' and about 10 tonnes heavy ship weight. We used a 44 lb Bruce on 275 feet of10 mm chain. We had a long 16mm nylon rode spliced to its end, but in 17 years and 86,000 miles (Mexico and South Pacific) we never needed the extra length. I hope that this data will help your decisions.

Cheers,

Jim

[RabidRabbit]

I've only been out 2 years and heres what I did/spent for anchor system on my ODay 32 Now we all know this is not a fancy or even ok sailing boat. It's a dog.
Maxwell vertical winch $2000
200' 3/8 chain 385 lbs $800
Batteries and tinned 0/0 cable $1000
55# plow, 44# claw $400
25# CQR, 25# DAnforth -came with boat
So I carry 500lbs on the bow and it works great. I sleep very well and its high on my list to get a 65lbs spade of some sort. I dont care for peter smith much and would rather buy from someone who ripped off his R&D.