All Chain Rode . . . Overkill ?

[colemj]

Originally Posted by Bash

Rule of thumb: the larger the boat, the less likely it will be to use nylon. When did you last see a ship anchor on nylon?

My guess is that somewhere around 13 meters LOA the combined rodes disappear, at least among cruisers. On my boat (14 meters) I still use nylon on the stern anchor, but wouldn't dream of it for the primary.

Racers and racer/cruisers are a whole 'nother matter.

I agree with all of that, but the reasons have nothing to do with increasing the holding power of the anchor during a blow and more to do with the convenience of all chain and the ability to carry the weight, store and handle it.

I think combined rodes disappear almost entirely around 10 meters for boats out cruising, solely for convenience sake. And I think if boats smaller than that had the room, handling and carrying capacity, they would be on all chain also - again for convenience, not for holding power.

Mark

[craigsmith]

He's right: our boats all lie on a spectrum between a toy boat and a large ship. The best way to anchor the former is with a relatively large anchor and a piece of elastic... the best way to anchor the latter is with a relatively small anchor and heavy chain (large ships are also forced into using smallish anchors that also must be symmetrical types, for the ability to handle and stow them. They don't have to handle significant dynamic motion so for the most part it's okay [although the anchored ship running its engines in slow ahead during a blow might disagree]). The thing is, most of the tradition that has survived the 20th century that is mindlessly rehashed over and over again wherever you turn originated from the larger end of that scale, where it does apply, but becomes more and more incorrect the smaller you go.

In the photos above Kiwi Roa is on 100% chain with no snubber, as stated it was not required. When it is required the camera lens won't stay clear long enough to get a shot . She carries 100 m of chain - the length is required by some of her intended destinations, deep coral anchorages in the Pacific or deep rocky mountainsides in Antarctica, etc, plus it's just convenient for it to hardly ever leave the windlass, and she's a big heavy displacement boat that can afford to carry the weight. Plus 50 m polyester to complete the main rode if/when more than 100 m is needed. A snubber is added a very small percentage of the time. This percentage would increase if the boat size was reduced until it becomes near mandatory in the majority of conditions around maybe 8 m.

But even for our larger heavier yachts, heavy chain does very little for the anchor. You don't carry chain for performance of the anchor by way of catenary. The likes of Steve Dashew - big anchor, light high tensile chain (even on an 84' boat) have it figured out.

[Factor]

For what its worth I have often struggled with the concept of kellets, heavy chain etc and thought centuries of truisms must be based on - well - truth. I started to research everything I could find and was struck over the last few years by two clear schools.

the - kellets and heavy chain and traditional anchor school invariably have no empirical data for me to examine. The obverse invariably has at least some empirical data.

There is a message in there about dispassionate assessment of evidence.

Doesnt mean I accept what people say - but some items of the rocna philosophy are blindingly obvious - like if you are going to carry around a kellet - why not carry that weight around in the anchor?

Irrespective of the anchor at the end of the system, the other items Craig talks about appear to have some merit and are worthy of more reflection.

So what have I got - its a plough (brand name) with 50 metres of chain. Its crap and I dont like it but I am still trying to work out the answer.

[Doug Wood]

Primary for 25 years has been a 44 lb. Bruce and 300' of 5/16 HT chain. Somehow I don't like the weight in my bow but my main preference is to keep my boat floating and safely anchored so I can sleep well at night.
I'm no physicist, but 35 years of actually anchoring a monohull sailboat in the Atlantic, Carribean ad Great Lakes have clearly illustrated to me that the more horizontal to the bottom I can keep the pull on the shank of my anchor, the better and longer it will hold and not break out. Given the fact that chain is heavier than rope, regardless of the amount of scope, the pull has remained more horizontal, longer with the heavier of the two materials.

[s/v Beth]

You will notice that a few of the posts were removed. No matter what the topic, we need to be polite to one another...

[sck5]

I have a Caliber 33 and a Rocna 20. I use 5/16 hi test and have 125 ft. of chain and then 100 ft of nylon. Sure, it would be better to have all chain but then there is a hell of a lot of weight up front. Besides, if I have, say 175 ft. out, then the nylon part isnt going to be on the bottom. There are also limitations on what the windlass can lift. The anchor itself is 44 pounds and with the chain, shackles, etc. I am looking at close to 200 lbs. So far, this has worked for me. I also have another 50 ft. of chain I can put on if conditions warrant but so far they never have.

[Weyalan]

When we are racing we carry a 45 pound plough, with 40' of 3/8" chain and 165' of nylon rope (Note: Many other racers laugh at me for carrying a bigger anchor than the regulations require)

When we are cruising I carry a 45 pound plough with 165' of 5/16" chain and 35' of nylon rope. (Note: We are not, currently, anywhere near coral)

[SabreKai]

Originally Posted by svcambria

only to consider going with 275 feet of 5/16" - then you can shop for a half drum at the chain supply places rather than chandleries...

Michael

Thanks, And I just realized my math was wrong. My bow is about 3 feet out of the water, so 300/5 gives me 57 feet not 45. Doh! 275/5 gives me 52 feet so that works out just ducky. I'll go with the 275.

A good bit of shopping just provided me with a nice Lofrans Royal windlass, with the 5/16HT gypsy. Scored that for $650 from a fellow swallowing the anchor. So I'm a happy camper tonite, and having a tot to celebrate.

Sabre

[hummingway]

Nice score Sabre.

A few people commented on the need to snub or cleat .... I do both. I had an undersized shackle break on the snubber that came with the boat, with a nasty twang I'll tell you, so decided to always use both. The snubber I built is heavy and long and had a rubber shock absorber wrapped about twenty times in the middle of it and really makes the ride more comfortable. Once I've got enough chain out I snap on a shackle and cleat off, go back and test my holding then put the snubber on and reset the cleat line. A little extra work and a bunch of security.

[sam_uk]

reading this Forces lead me to the conclusion that there is nothing wrong with Nylon.

The bit of chain from your bow to the bed does nothing but drag your bow down.

Rode - Dynamic Behavior

[Dockhead]

Originally Posted by colemj

On both sides of this, I would say. To dismiss someone's argument because you don't agree with it is arrogance, if not hubris.

No one made the argument that, at lesser wind conditions, nylon has the same cantenary as chain. In these conditions, the anchor is holding the boat regardless of the type of rode or amount of cantenary induced in it.

When the wind picks up to a level most of us become concerned about, the chain and nylon WILL have the same cantenary effect on your anchor's holding power - none, they both will be straight. The pictures from two different posters showed this clearly without the need to don a mask and snorkel. At this point, you are relying solely on scope to present a proper pull angle to the anchor shank and any elasticity in your rode to absorb shock.

In conditions between no wind and OMG, the effect on the anchor from the cantenary of all chain rode will be matched by the elasticity of the nylon rode. The calculations for this are readily available and links to them have been presented in this thread. Of course, you are free to disagree with the math and physics using your own reasoning and data, and doing so will be very welcomed in these discussions.

I can think of many reasons why an all chain primary rode is preferable (it is what we use), as well as why a combination rode would be preferable (it is what we used to use in different cruising grounds). Each has its place in relevant situations and styles. None of those reasons have to do with keeping the anchor set in difficult weather.


Mark

Very well put.

I think that it has been pretty well proven that a chain rode, no matter how heavy, will not help you once conditions get tough. At a certain point the catenary disappears, and that is the point when you would most like to have it.

So a chain/nylon rode will have no disadvantage in terms of holding power and will have big advantages in terms of weight in your bow and elasticity. Since it's much lighter, you can carry more of it, too, giving you a chance for more scope.

Despite all of this, we use all-chain, like most cruisers. The main reason is chafe, which is a nightmare in a survival anchoring situation. Or maybe the main reason is laziness; you have to deal with the rope/chain transition when handling a rope/chain rode; you have to have a suitable capstan drum, etc. Rope/chain might really be better; we carry 100 meters of 12mm G40 chain, which weighs a good part of a ton.

[Dockhead]

Originally Posted by hummingway

Nice score Sabre.

A few people commented on the need to snub or cleat .... I do both. I had an undersized shackle break on the snubber that came with the boat, with a nasty twang I'll tell you, so decided to always use both. The snubber I built is heavy and long and had a rubber shock absorber wrapped about twenty times in the middle of it and really makes the ride more comfortable. Once I've got enough chain out I snap on a shackle and cleat off, go back and test my holding then put the snubber on and reset the cleat line. A little extra work and a bunch of security.

I do exactly the same. I tie my snubber off with a rolling hitch and I also belay the chain near the windlass with a short line and chain hook. Otherwise, what would happen if your snubber were to snap or rub through?

I was anchored last week in a bit of a blow after crossing the Channel from Cherbourg, and got concerned about chafe on the snubber running over the rail. I decided to rig the snubber through the second bow roller so it worked over the roller. I attached it to a dockline rigged between the two bow cleats. Wonder if any of you guys have tried this? Worked very well.