Cruising Anchor Chain Length

[Sandydog]

Seems to me the weight of chain in the water having any significant advantage of holding power of the anchor is insignificant. Of course in coral and rock, yes because of chafe.

[Minggat]

[QUOTE=roverhi;2991144]Always used a 30' 5/8" three strand nylon snubber.

The problem with rope rode is abrasion where it passes through chocks on the boat. Stretch under a heavy load will pull the line past the chafing gear leaving the line unprotected. From experience it is no fun trying to add chafing gear to a line where it passes through a chock in 40k winds. QUOTE]

Glad to hear this mentioned.

All of this goes around and around with so many good points going both ways on line vs chain. In the end, that's the one point that weighs most heavily with me.

All chain has served me well.

On a mooring off of Maui once when I got caught in a Kona wind episode. My bridle to the mooring became the weak point, so no chain to my boat. Had there been chain, it would have been a different set of problems.

My 2 each 3 strand nylon got reduced to only 2 strands of one bridle , as the other had snapped. Before it snapped, the 2 bridles had twisted around each other and abraided down to leave me just the 2 out of 6.

Fired up the engine, ran forward to cut the remaining bridle and got over to the lee of Lanai. Spent the bumpy night there on all chain. A snubber up to the task would have been very nice.

[s/v Jedi]

So many anchoring posts (I’ve done hundreds here) and still so many that didn’t get it right. Here it is once more:

1. Determine the biggest anchor that fits on your roller, then try one that is one size up from there. This is where putting money in makes more sense than a more expensive insurance policy.

2. Get a strong, vertical windlass with enough room underneath for a high, narrow chain locker. If that needs to go further aft to get enough height, go further aft. Mine is 14’ aft of the bow.

3. Between windlass and roller, create a strong point and mount a chain stopper like the one from Maxwell.

4. Get at least G4 chain. If you can’t fit 400’ / 120m of that in the chain locker then go down one size and up to G7 grade. Get the shackle to match that grade, they do exist, or order the chain with enlarged end links at both ends (so that you can turn it over end for end to extend lifespan.

5. Get 400’ / 120m of chain, no rope at all. What I tie to the inboard end is small diameter, floating polypropylene rope to function as a marker in case the whole sjebeng goes overboard... intentionally or not.

6. Get a spare anchor, same size as the primary. Consider the Mantus that can be disassembled for easy storage. You will use this when the primary anchor is lost, or in very rare cases like cat 4-5 hurricanes without even mangroves around to hide in. If you already have a Mantus then this is the excuse to buy the new model

7. Get a second (kedge) anchor. Consider a light weight Fortress that is easier to handle with the dinghy. This will be used when anchoring on waters with tidal flow and little room, like rivers, or as a stern anchor on the beach when there is no palm tree, or when hiding in mangroves etc.

8. Get a second rode, consisting of 20’ of chain, spliced to 300’ of nylon. This will normally be used with the second anchor, unless the primary rode is lost.

9. Search this forum for the Jedi 99% anchoring rule

[Paul L]

Well Jedi those are some pretty non-flexible, didatic rules. Pretty good for a world cruiser, a little overkill for cruising the ICW.
Also not sure of you upping the ante to 120m of chain. Most US long distance cruisers go with 300 feet. Then when you switch to metric you you round to 100m = 328feet.
We use a 100m of 10mm G4 chain.

[noelex 77]

Originally Posted by kev_rm

Show me a picture. I don't think this is even remotely accurate.

A picture beats 1000 words. I have lots of photos . I have already posted a photo of the chain leading to a Rocna (see post #12). This was with an all chain rode (not chain and rope combination) in 25 knots. 5m @ 4:1.

Here is another example:
This was also an all chain rode, rather than chain and rope.
This was an Ultra anchor in 6m of water @3.5:1. The wind was 25 knots with gusts to 30.





Another example. This was also in 25 knots of wind. In this case there is not only the chain, but a Rocna anchor that is acting as a kellet and adding to the chain weight. Nevertheless the total weight of chain and anchor is lifted off the bottom.



Or this Delta in 25 knots 8m 4:1.



These examples show boats with an all chain rode rather than a chain rope combination, but the latter will only make things worse. The exact windspeed where all the chain will be lifted depends upon many factors such as the scope, the thickness of chain relative to the size of the boat, the windage and displacement of the boat etc etc, but with only 30m of chain available my estimate is that the chain will be lifted and that the catenary will be essentially lost at around 20-25 knots of wind. I think this is a reasonable ball park figure.

The only caveat I would add is that some sailors, especially those less experienced at anchoring, sometimes overestimate the force when judging wind-speeds they are experiencing. I am talking about a genuine 20-25 knots not 10 knots with occasional gust into the low 20s that is sometimes loosely referred to as “it was blowing 20-25 knots last night”.

[s/v Jedi]

Originally Posted by Paul L

Well Jedi those are some pretty non-flexible, didatic rules. Pretty good for a world cruiser, a little overkill for cruising the ICW.
Also not sure of you upping the ante to 120m of chain. Most US long distance cruisers go with 300 feet. Then when you switch to metric you you round to 100m = 328feet.
We use a 100m of 10mm G4 chain.

Yes, this a cruisers forum as in blue water. Also, the OP clearly indicated world cruising, so there’s no room for lake dwelling danforth options or little strings for rode

Cruisers who go for 300’ instead of 400’ do this mostly for two reasons: their chain locker can’t take more and/or for budget reasons. They often voice the 300’ is enough argument instead, because it sounds better

Yes, 300’ is enough, which is why the second rode Is 300’, but you will often use 200’ and when you have 400’, then you have an almost unused 200’ available when you turn the chain end for end, so you increase lifespan making up for higher initial cost, while always having another 100’ just in case. There are anchorages with more than 100’ depth, like Alexandria, where one must be able to anchor and 300’ is too skinny.

In your case, you have made your choice for 328’ of G4 10mm chain. But you now know that 400’ of G7 8mm chain is a better option so when the time comes to replace the chain, and a 8mm or 5/16” chain wheel is available, then you will remember this

[Michael Graham]

After nine years in the Med I'm about to replace our 12 yr old chain. I'm increasing from 80 m to 100 m as there have been a few occasions when 80 m has not been enough when anchoring stern on in gale force winds in a deep bay like Symi in Greece.

Similarly the extra length will come in useful in some of the very deep Turkish bays.

[Paul L]

Originally Posted by s/v Jedi

Yes, this a cruisers forum as in blue water. Also, the OP clearly indicated world cruising, so there’s no room for lake dwelling danforth options or little strings for rode

Cruisers who go for 300’ instead of 400’ do this mostly for two reasons: their chain locker can’t take more and/or for budget reasons. They often voice the 300’ is enough argument instead, because it sounds better

Yes, 300’ is enough, which is why the second rode Is 300’, but you will often use 200’ and when you have 400’, then you have an almost unused 200’ available when you turn the chain end for end, so you increase lifespan making up for higher initial cost, while always having another 100’ just in case. There are anchorages with more than 100’ depth, like Alexandria, where one must be able to anchor and 300’ is too skinny.

In your case, you have made your choice for 328’ of G4 10mm chain. But you now know that 400’ of G7 8mm chain is a better option so when the time comes to replace the chain, and a 8mm or 5/16” chain wheel is available, then you will remember this

I have a fair amount of experience anchoring deep across the South Pacific and other places. Night before last we anchored behind a reef in 80-90 feet. No surprise, we didn't drag😁

I do not like G70 chain. I had it before the current lot and the galvanizing shop refused to regalvanize it because it was G70. When you want to a get a chain regalvanized while cruising you do not have choices of different galvanizing shops.

So, no I don't now know that I should have bought g70 at 120m length. Geeze, its a cruising site with a huge range of cruising styles - some are even different than yours.

[s/v Jedi]

Originally Posted by Paul L

I have a fair amount of experience anchoring deep across the South Pacific and other places. Night before last we anchored behind a reef in 80-90 feet. No surprise, we didn't drag😁

I do not like G70 chain. I had it before the current lot and the galvanizing shop refused to regalvanize it because it was G70. When you want to a get a chain regalvanized while cruising you do not have choices of different galvanizing shops.

So, no I don't now know that I should have bought g70 at 120m length. Geeze, its a cruising site with a huge range of cruising styles - some are even different than yours.

Listen, my recommendations are rarely the most economical options. In the case of G7 chain, those galvanize shops had a point because regalvanizing G7 does not guarantee load specs are retained. It is a chain that is better replaced after the factory galvanize wears off and rust is winning. This is where having mostly unused 200’ in the locker gives it that extra life when turning end for end.

I agree that 100m chain is all you need to anchor at 25m depth. But at 35-40m you run out of options and those anchorages do exist for world cruisers.

On cruising styles: I know I come over too forcefully or even arrogant for others. This is mostly due to cultural differences (Dutch, blunt, direct, no beating around bushes), add to that a life of sailing where I have seen and experienced it all. I can ensure you that I’m not trying to insult you or joke around or anything. It’s just that I don’t accept compromise on primary systems aboard blue water cruisers which is what we talk about. The OP has not made the choice yet and asks this forum. I do not give him options that will probably work out okay... I will recommend the option that will enforce success even when things turn bad, shops, help is non existent, named storms upon us etc. Please don’t take that as an attack on your setup which does not (almost but just short) meet my recommendation. You don’t need to defend your setup but also not insist that it is the right choice for somebody about to do the investment. I present a gold standard and let him make a compromise himself if he needs to.

If you could fit 400’ of G43 10mm chain in your locker, would you tell the OP that 300’ is still the better option?

There are more options; I have been experimenting with a G7 chain splice link and like it enough to keep using it. But I won’t recommend it as long as OP may find room for 400’ even when that requires tricks like putting the first 100’ in the bilge, then up and into the chain locker for the other 300’. The reason is that the link can jump off the gypsy and cause trouble.

Another approach would be to say something like 300’ minimum, 400’ is better. The things that I know of places where 300’ doesn’t really work, while I have never heard of a place where 400’ doesn’t work

[Paul L]

Jedi,
I forgot the cultural differences. We are currently cruisng with a Dutch couple and she is constantly stopping to grab her words and say Oh, that's just the Dutch direct way.

In my English it sounds like you are telling everyone what tbey have to have and anything less is undeniably wrong�� Clearly with your explanation I understand it is more a Dutchism.

I don't buy having a 400ft chain and end for ending gets you longer life. I end for end my 300 ft chain and also get a longer life before needing to regalvanize. We most tupically have 125ft out. If you wait too long to do end for end, then the switched end that now never gets used just turns into a rusting hulk.

[Auspicious]

Late to the party.

Originally Posted by myocean

noelex 77, this is very interesting to read. Have there been tests carried out on that topic?
From my point of view situations where you need holding in very poor substrates are as common as situations with strong wind. So, a long chain is quite helpful in many cases.

There have certainly been tests. Noelex 77's pictures are a pretty clear demonstration.



Anchor tests in general are pretty useless for what sailors want to use them for. Not enough trials to be statistically significant and no meaningful measurement of environmental conditions (e.g. sheer strength of the substrate).


Essentially anchor tests are compilations of anecdotes and opinion. There is no science there.



There are some analyses that are first rate, such as the one by Alain Fraysse (Tuning an Anchor Rode). The engineering math is pretty straightforward and there is nothing magic about it. You can take it to the bank. I've used the same equations to calculate catenary and tow body depth for side scan sonar.



I'll also point out that discussions of scope in this thread in a couple of places reflect the all to common mistake of considering scope as a function of water depth. It is not. It is a function of water depth plus the height of the bow roller above the water. If you put out 50m of rode in 8m of water with a bow roller 2m above the water your scope is 5:1, not 6.25:1.

[sailorboy1]

anchor threads alway become a "I'm right and you are wrong" battle like there really is a "right" answer that must be followed

in the end it doesn't matter what you use as, long as it holds and you can sleep knowing what you have

Me, I have all chain mainly due to the convenience of not having to deal with the rope/chain transition. I have 300' because that's all that fits well (still need to be rearranging in the locker while bringing up) and mostly rarely use more than 120'. My boat doesn't care rat's a butt about the weight. It has never dragged once set and only failed to set 3 times.

It's only a anchoring system, it isn't rocket science.

[Auspicious]

Originally Posted by sailorboy1

It's only a anchoring system, it isn't rocket science.

Rocket science is simple. The point end goes first and the fire comes out the back.

[jmh2002]

Steve Dashew has written multiple good articles on topic of Anchors, Chain, & Anchoring, even if some are in relation to bigger vessels, all of the points are still relevant.


https://setsail.com/anchoring-system-logic/

https://setsail.com/anchoring-system-logic-2/

https://setsail.com/anchoring-system...true-approach/

https://setsail.com/forepeak-anchoring-system/

https://setsail.com/lee-shore-why-yo...oring-systems/

https://setsail.com/anchor-snubber-lines/

https://setsail.com/chain-stacking/

https://setsail.com/handling-anchor-chain/

https://setsail.com/bigger-is-better-with-anchors/

https://setsail.com/how-big-should-your-anchor-be/

https://setsail.com/anchoring-in-heavy-weed-and-kelp/

https://setsail.com/anchor-system-rants/



You can also download his books here, for free:

https://setsail.com/free-books/

[daletournier]

Originally Posted by s/v Jedi

Listen, my recommendations are rarely the most economical options. In the case of G7 chain, those galvanize shops had a point because regalvanizing G7 does not guarantee load specs are retained. It is a chain that is better replaced after the factory galvanize wears off and rust is winning. This is where having mostly unused 200’ in the locker gives it that extra life when turning end for end.

I agree that 100m chain is all you need to anchor at 25m depth. But at 35-40m you run out of options and those anchorages do exist for world cruisers.

On cruising styles: I know I come over too forcefully or even arrogant for others. This is mostly due to cultural differences (Dutch, blunt, direct, no beating around bushes), add to that a life of sailing where I have seen and experienced it all. I can ensure you that I’m not trying to insult you or joke around or anything. It’s just that I don’t accept compromise on primary systems aboard blue water cruisers which is what we talk about. The OP has not made the choice yet and asks this forum. I do not give him options that will probably work out okay... I will recommend the option that will enforce success even when things turn bad, shops, help is non existent, named storms upon us etc. Please don’t take that as an attack on your setup which does not (almost but just short) meet my recommendation. You don’t need to defend your setup but also not insist that it is the right choice for somebody about to do the investment. I present a gold standard and let him make a compromise himself if he needs to.

If you could fit 400’ of G43 10mm chain in your locker, would you tell the OP that 300’ is still the better option?

There are more options; I have been experimenting with a G7 chain splice link and like it enough to keep using it. But I won’t recommend it as long as OP may find room for 400’ even when that requires tricks like putting the first 100’ in the bilge, then up and into the chain locker for the other 300’. The reason is that the link can jump off the gypsy and cause trouble.

Another approach would be to say something like 300’ minimum, 400’ is better. The things that I know of places where 300’ doesn’t really work, while I have never heard of a place where 400’ doesn’t work

Hi Jedi, your approach is very solid, yet it is just your opinion. You aren't the only one that has cruised a long time or anchored deep.

Shock horror, I've gone from 120m down to 80m. My experience in places like raja ampat Indonesia (amongst others) etc where you often have to anchor deep is that less scope is actually required. 3:1 is generally fine when anchoring in 20-25m.

In regards to anchoring in 30m+, I wont, I will move on, 30m+ is crazy deep, it's a problem if you are fouled ,its a problem for many windlasses etc, yes I know your windless can handle it .

Yes, bigger, stronger and more is better BUT where does that stop?,do I buy a ship?

Many successfully go around the world with 100m of chain or less.