Chain Versus Rope Scope ?

[JoeFish]

Originally Posted by Bash

That's crap. Ship rodes and yacht rodes are chain for the same practical reasons.

That's also physics.

I'll simply quote a study that's far more authoritative:

"This way of doing things has been reinforced over thousands of years, mostly with relatively large vessels, and has built a strong tradition. Ships from all eras have used very heavy chain, and relatively small and ineffective anchors. This for the most part works well. Unfortunately, the relevant factors do not scale down evenly to smaller boats such as today’s cruising and pleasure yachts. In fact, the best way to anchor a toy boat in the garden pond is with a relatively large toy anchor and a rode consisting entirely of an elastic line. Between this extreme and that of large ships, a compromise needs to be found.

Recognizing that a small boat is not a ship is the first step. While ships have massive inertia and waves/swells do not normally bother them, a yacht or motor-boat is subject to comparatively violent surge, and winds which are very high on a relative basis. As such the forces are relatively higher, and on the other hand small boats can carry anchors which are, for the size of boat, quite large. If a 10 m yacht carries a 15 kg anchor, this anchor scaled to fit a large container ship would simply be too massive to be practical.

It is then important to critically examine the mathematics of the catenary curve of a boat’s chain to investigate its true usefulness to a small boat. As the above “old way of thinking” is commonly adhered to, it is a widespread myth that all boats should carry as much chain as possible – and the heavier the better.

In fact, we shall see that catenary rarely offers much benefit which is truly worthwhile, and any unnecessary extra weight of the chain is often far better invested in other elements of the anchoring system."

Assuming that your vessel at 1/1000th the mass of a container ship is subject to similar relative environmental forces is simply absurd. Maybe in a mill pond on a windless day, but not in conditions we are talking about. The relative forces in play for small boats is radically different than it is for large vessels and the strategy needs to adapt accordingly.

Not to mention it would be impractical to moor a 220,000 ton container ship with nylon braided rode.

Physics is physics, but different factors come into prominence at different scales when environmental factors are the constant.

[JoeFish]

Originally Posted by wolfenzee

At present I carry 300' of chain (also 250' of rode w/25' of chain) ...scope I use depends on the bottom, weather and anchor, useually I use a 22 lb. Bruce primary anchor, but also have a 20 lb CQR and 45 lb Forfjord (and 15 lb northill I run off the stern when anchored in a river as a seconond anchor).

That's at least 502 lbs if the bruce is on the roller (assuming 3/8 chain). All that weight concentrated in the bow of your boat, assuming the rest of the rode is either weightless or stowed elsewhere along with all those other anchors).

Imagine what that does to your pitching moment in 10' seas. No thanks. Not even in my 20,000 lb boat. Downwind in big waves I want all the buoyancy forward I can get and I'm not going to schlep 400+ lbs of anchor chain every time it threatens to blow a little.

With a heavier anchor stowed properly amidships, 25-60 feet of chain stowed low, 12 feet aft of the bow, and a couple hundred feet of brait I've got a bullet proof anchoring system I can deploy in seconds and I'm not destroying the performance or sea keeping capabilities of my yacht.

It's worth thinking about.

[wolfenzee]

Originally Posted by JoeFish

That's at least 502 lbs if the bruce is on the roller (assuming 3/8 chain). All that weight concentrated in the bow of your boat, assuming the rest of the rode is either weightless or stowed elsewhere along with all those other anchors).

Imagine what that does to your pitching moment in 10' seas. No thanks. Not even in my 20,000 lb boat. Downwind in big waves I want all the buoyancy forward I can get and I'm not going to schlep 400+ lbs of anchor chain every time it threatens to blow a little.

With a heavier anchor stowed properly amidships, 25-60 feet of chain stowed low, 12 feet aft of the bow, and a couple hundred feet of brait I've got a bullet proof anchoring system I can deploy in seconds and I'm not destroying the performance or sea keeping capabilities of my yacht.

It's worth thinking about.

In a 10' sea the boat goes through the wave with the spray pushed off to the side. Actually the bow on my boat has a lot of flair(see below), the purpose of this extra bouyancy is to keep the cockpit dry...this has a tendancy to make the boat a bit "saucy"...this is counteracted by the wieght of the chain, balnce diffrance is counteracted with a heavier engine. She still sits at her deasign waterline perfectly level (bulkheads are bubble plumb). Spare anchors are lashed to the boom gallows.

[wolfenzee]

If your boat is the "Sparkman & Stephens, Design 1068 Nevins Yawl" Sparkman & Stephens: Design 1068 - Nevins Yawl or something close (as your specs seem to suggest) I can see why you stow your anchor and ground tackle as you do...but we have different boats.

[JoeFish]

Originally Posted by wolfenzee

If your boat is the "Sparkman & Stephens, Design 1068 Nevins Yawl" Sparkman & Stephens: Design 1068 - Nevins Yawl or something close (as your specs seem to suggest) I can see why you stow your anchor and ground tackle as you do...but we have different boats.

Yes, that's it, but pitching moment is pitching moment. What makes you "see why I stow the anchor and rode where I do?" The performance speaks for itself on any boat when you centralize mass.

Bringing that mass more central is not going to do anything other than improve your boat's sailing performance so long as you maintain proper trim.

[Strait Shooter]

Great discussion!
Thanks everyone!

Would an all chain rode with a long nylon bridle not be ideal? Barring of course the weight distribution issue which is really more about boat design and getting the weight low and back.

[JoeFish]

Originally Posted by Strait Shooter

Great discussion!
Thanks everyone!

Would an all chain rode with a long nylon bridle not be ideal? Barring of course the weight distribution issue which is really more about boat design and getting the weight low and back.

Did you read the article? If not, I'll paraphrase the author (designer of the Rocna anchor):

It is then important to critically examine the mathematics of the catenary curve of a boat’s chain to investigate its true usefulness to a small boat. As the above “old way of thinking” is commonly adhered to, it is a widespread myth that all boats should carry as much chain as possible – and the heavier the better.

In fact, we shall see that catenary rarely offers much benefit which is truly worthwhile, and any unnecessary extra weight of the chain is often far better invested in other elements of the anchoring system...

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....

Sufficient length is required to get any measurable shock absorption from brait type rode.

The quote above is selective and I'd encourage you to read the article and evaluate your requirements based on a number of the factors mentioned therein. If you're n Patagonia your needs will be different than the Bahamas. There is no single right answer, only general rules (as in life).

As mentioned, I favor brait with a short length of chain (25-60 ft) and adjust depending on conditions and depth.

A means of sampling the bottom is also a good addition to your anchoring kit.

[Strait Shooter]

I did read the article. It's o.k. with you if I question or disagree isn't it? I don't usually blindly follow anyone or anything.

So explain to me why you feel a chain rode with a long nylon bridle is bad. You didn't do that, you sound like you're kinda blindly following a specific article.

I'm just asking a question.

[Strait Shooter]

So if you have an all nylon rode, maybe some chain on the end and it parts because of chafe or whatever in nasty conditions, you wouldn't like to have a chain attaching your boat to the bottom?

What's so wrong with having the best of both worlds?

[Strait Shooter]

Just because he's the "designer of the Rocna anchor" (fan fair and rose petals) doesn't mean he's the all knowing answer guy does it?

I work with lots of engineers and designers and am not as easily impressed perhaps.

A physicist? I use heavy chain, cable and rope to move big heavy things on a daily basis, not on paper. If I put you a 1,000 feet in the air on your 20,000 lb boat and started bouncing you up and down I bet you'd think a little differently as to what you think you need.

[JoeFish]

One reason is I got the same advice from Olin Stephens when I asked him years ago and I trusted his expertise.

Another reason is I have used this technique in locations ranging from the Sea of Cortez to the Bahamas, Bermuda to Maine, Greece to Sweden, the Pacific Northwest and I have yet to have any problem. I've ridden out tropical storms with 8:1 using only 60 feet of chain and never dragged my anchor.

However it's worth noting that I own 5 different anchors and I usually have two on the boat most suited to the area I'm sailing in.

Typically I have a Bruce and a Danforth style (Fortress) for almost all areas. I have a small yachtsman I use as a lunch hook, and a larger one I rarely use (it may be the original anchor on the boat). Both collapse and I've used them with success.

I also have a CQR but I have not used it in ages. I plan to sell it and replace it with a Rocna at some point in the future as I'm inrtigued by the design. It could replace the Bruce, but we'll have to see.

The Bruce and the Fortress are larger than suggested (66 and 47 lbs.)

As others advised me, I put the weight into the anchor, not the rode.

The point of rode elasticity is to reduce peak loading on the anchor which may rip it from the bottom and to reduce loading on your deck hardware. It's a very different objective than you have when lifting things.

[Strait Shooter]

Originally Posted by JoeFish

One reason is I got the same advice from Olin Stephens when I asked him years ago and I trusted his expertise.

Another reason is I have used this technique in locations ranging from the Sea of Cortez to the Bahamas, Bermuda to Maine, Greece to Sweden, the Pacific Northwest and I have yet to have any problem. I've ridden out tropical storms with 8:1 using only 60 feet of chain and never dragged my anchor.

However it's worth noting that I own 5 different anchors and I usually have two on the boat most suited to the area I'm sailing in.

Typically I have a Bruce and a Danforth style (Fortress) for almost all areas. I have a small yachtsman I use as a lunch hook, and a lager one I rarely use (it may be the original anchor on the boat). Both collapse and I've used them with success many times.

I also have a CQR but I have not used it in ages. I plan to sell it and replace it with a Rocna at some point in the future as I'm inrtigued by the design.

The Bruce and the Fortress are larger than suggested (66 and 47 lbs.)

As others advised me, I put the weight into the anchor, not the rode.

And again, my question is, why not both?

[JoeFish]

1) simplicity
2) necessity

I see good reason for #1.

I do not see where #2 has greater importance than #1 when there is no evidence #2 will outperform #1. If you can produce a series of real world tests where both provide better performance than the simpler solution then you will have your answer.

Smarter people than I gave me this advice years ago. I listened to them and I have yet to have reason to doubt their advice. Until I have a reason to suspect their advice is flawed or see evidence that some other strategy yields better performance I can't see any reason to adopt new tactics.

[JoeFish]

I should add that no one has given any evidence beyond the subjective that all chain rode is in any way superior. In fact, there's plenty of data out there to contradict that assertion given proper set of the anchor (a poorly set anchor might be one case where all chain is superior, but that also has yet to be proven).

While there's plenty of historical precedent with larger craft and all chain rode, it's been pretty convincingly proven that smaller vessels have different dynamic requirements for their anchoring systems.

If there is a study that shows any more conclusively that all chain is better and offsets the obvious weight and stowage problems then I'm more than willing to consider it, but I don't see anything out there that meets any kind of reasonable evidentiary requirement at the moment.

[sailorboy1]

I have an over-sized anchor and 340' of chain (with some rope to attached it to the boat), and 30' rope snubber. The weight of the anchor and all that chain to my boat isn't worth worrying about! If you have older sea-saw designs maybe you have to consider things different.

You can spin any story anyway you want. But you never are going to convince me that an over sized anchor, all chain rope, and good snubber setup is not the best way to go!


I've read these threads for years. And I've read other articles by "experts" being quoted here on the thread where they made the "don't use all chain" option. But in those articles they still normally recommend 3 times the boat length in chain, which for most anchorages in effect becomes all chain.

PS - just how long a snubber do you have to have before the all chain "downside" is gone.