How much chain

[DocMolarboater]

That’s my philosophy too. Existing chain is “questionable” and Rocna recommends 3/8”. My only real question is how much?
I’ll put on a new gypsie if necessary.

I do use Nylon 3 strand bridle for “shock absorption”.

 

[rslifkin]

Rocna, like other anchor manufacturers seems to want to size chain to the anchor. In my mind, that's pointless. Chain should be sized to the load the boat will put on it. If the anchor is oversized and set in a really good bottom, it'll hold more than the working load of the chain, but that's fine, as if the chain is sized well, the boat will never pull hard enough to hurt the chain.


My 73lb Vulcan should be paired with 3/8" G43 chain according to Rocna. But I'm happily using it with 5/16" G43 as in no universe will my boat (38 feet plus bolt-ons and a bit over 27k lbs) pull hard enough to exceed the working load of the 5/16" chain in anything less than a full hurricane.

 

[DocMolarboater]

My 73lb Vulcan should be paired with 3/8" G43 chain according to Rocna. But I'm happily using it with 5/16" G43 as in no universe will my boat (38 feet plus bolt-ons and a bit over 27k lbs) pull hard enough to exceed the working load of the 5/16" chain in anything less than a full hurricane.

I don’t know how to calculate the pull of a 51,000 Lb boat vs WLL of chain.

It’s very confusing. I can look up what a WLL is for a given size and type of chain but to me it’s just a number that I have no reference for.

What do you base your decision on regarding not reaching WLL of chain? I’m eager to learn more.

 

[rslifkin]

I don’t know how to calculate the pull of a 51,000 Lb boat vs WLL of chain.

It’s very confusing. I can look up what a WLL is for a given size and type of chain but to me it’s just a number that I have no reference for.

What do you base your decision on regarding not reaching WLL of chain? I’m eager to learn more.

I used a few sources of data where people have measured anchor rode loading. One source I remember was: Forces


Based on the numbers at that link, a 40 foot powerboat will approach the 3900 lb WLL of 5/16" G43 chain if angled 30* off the wind. Straight into the wind, it's just under 1650 lbs of pull. Assuming the boat sails around a bit at anchor but has a good snubber to absorb shock loads, the peak load is probably somewhere between the 2 values. Add in the effect of wind gradient (the wind pushing on the lower part of the hull will be somewhat less strong) and the force gets reduced even a little further. Any sea state will add to the force.



A heavier boat may have higher peak loads from sailing around, so in 60 kts I wouldn't be surprised if the peaks were in the 2500 - 3000 lb range for your boat.


Depending on what conditions you want to size for, 3/8" G43 chain isn't overkill, but it's also likely more than necessary. Another option would be to go for 5/16" G70 chain if it'll fit your windlass and chainwheel combo (the links are slightly longer than 5/16" G43, so it may not fit). 5/16" G70 gives a WLL of 4230, so a bit higher than the 3900 lbs of 5/16" G43. Still a good bit lower than the 5400 lb WLL of 3/8" G43 though. Some of the small difference from G43 to G70 is due to how the WLL is calculated. For most grades of chain, it's 1/4 of the breaking strength, but for some reason, G43 WLL is typically calculated at 1/3 breaking strength.


Edit: Dug up another source: https://www.practical-sailor.com/sails-rigging-deckgear/the-load-on-your-rode

Based on the tested data in there from Robert Smith, if we assume a 50% addition for a high windage powerboat, that puts the load at 2250 lbs for a 42 foot boat in 60 kts. That further points to needing to be in hurricane territory before worrying about the strength of 5/16" G43 chain on a 40-ish foot boat.

 

[TBill36]

Don't forget to consider that your gound tackle is also your last resort in an emergency situation. Lose engines or tangled props in unprotected waters and you are going to want the largest ground tackle you can carry.

 

[DocMolarboater]

I used a few sources of data where people have measured anchor rode loading. One source I remember was: Forces


Based on the numbers at that link, a 40 foot powerboat will approach the 3900 lb WLL of 5/16" G43 chain if angled 30* off the wind. Straight into the wind, it's just under 1650 lbs of pull. Assuming the boat sails around a bit at anchor but has a good snubber to absorb shock loads, the peak load is probably somewhere between the 2 values. Add in the effect of wind gradient (the wind pushing on the lower part of the hull will be somewhat less strong) and the force gets reduced even a little further. Any sea state will add to the force.



A heavier boat may have higher peak loads from sailing around, so in 60 kts I wouldn't be surprised if the peaks were in the 2500 - 3000 lb range for your boat.


Depending on what conditions you want to size for, 3/8" G43 chain isn't overkill, but it's also likely more than necessary. Another option would be to go for 5/16" G70 chain if it'll fit your windlass and chainwheel combo (the links are slightly longer than 5/16" G43, so it may not fit). 5/16" G70 gives a WLL of 4230, so a bit higher than the 3900 lbs of 5/16" G43. Still a good bit lower than the 5400 lb WLL of 3/8" G43 though. Some of the small difference from G43 to G70 is due to how the WLL is calculated. For most grades of chain, it's 1/4 of the breaking strength, but for some reason, G43 WLL is typically calculated at 1/3 breaking strength.


Edit: Dug up another source: https://www.practical-sailor.com/sails-rigging-deckgear/the-load-on-your-rode

Based on the tested data in there from Robert Smith, if we assume a 50% addition for a high windage powerboat, that puts the load at 2250 lbs for a 42 foot boat in 60 kts. That further points to needing to be in hurricane territory before worrying about the strength of 5/16" G43 chain on a 40-ish foot boat.

This is an absolutely fantastic reply. Thank you very much for sharing your experience and knowledge.

 

[BobMc]

I'll have to take a beating on this, but I'm not a fan of all chain rode and don't like carrying the added weight.

The issue of weight is a non-starter. 300 pounds of chain on the bow is the equivalent of having a fair sized man and woman standing there. If that would be a problem on your boat, then there are other issues to consider!

 

[Nepidae]

We have a 43 Albin and builders certificate says 66K, but it's never been that in the slings.

Regardless, if your experiences on the Loop showed you that you would rarely anchor in deep, deep water then you probably don't need 300' of chain and you also don't need larger chain.

BTW, why are you replacing the chain? IF it is looks it might be less expensive to have the chain re-galvanized, replated.

We have 150' of 5/16 G4 chain backed by 250' 8plait line. We did our Loop over an 8yr period and never got to the 8plait.

I felt that IF we ever got past the chain, it wouldn't be that often so it would work.

NOW, that said how is your windlass set up? What size is the gypsy wheel and is it removeable and is there a replacement you can get for the different size chain. We have a LoFrans Tigress with a gypsy side and a drum side so if we ever got past the chain we could use the drum 1st to get back to the chain and then switch to the gypsy.

Any questions, PM me.

 

[rgano]

Changing chain size will usually mean changing chain wheel

AKA chain gypsy or wildcat.

 

[La Sirena]

300 feet of 5/16 sounds decent for your boat and cruising grounds. Why are you considering changing?

Peter

I'm with Peter. I think that chain size is appropriate for your boat. Selene does a nice job at designing and equipping boats with appropriate equipment. I would very carefully look into the anchor(s) though. And make sure you have an adequate snubber (bridle).

I have a Selene 57(~110,000 lbs) and I cruise from Maine to Bahamas. It has 2 anchors, each has 300 ft of 7/16" G4 chain. I rarely use more than 150'. The boat came with a Bruce and a Lewmar CQR (and a Danforth for a stern anchor). I replaced the CQR with a Sarca Excel and I'm very happy with it. I anchor out about 200+ days a year in varied locations.

When you look at damage at anchorages, it's never from a broken chain, it's always from an anchor dragging, or the rode wasn't fastened to the boat or anchor appropriately.

If you choose to go with 3/8" chain, you will definitely need to change your gypsy, and maybe need to add ballast in your stern. You should also contact the windlass manufacturer and make sure the windlass will lift that chain and anchor combination you choose. It may be too much weight for the windlass to lift.

By the way John and Gabi, you will love your Selene. They are great boats (biased opinion)! Hope to see you out on the water soon. Don't wait for everything to be fixed before you cast off. Only the important things.

 

[Mako]

When you look at damage at anchorages, it's never from a broken chain, it's always from an anchor dragging, or the rode wasn't fastened to the boat or anchor appropriately.

I’ve never read a single account on TF about someone’s chain breaking. Not even in a storm.

Considering that chain is generally sized with a 4:1 safety factor in SWL, I honestly believe that most people are ill-advised or suffering from fear tactics when it comes to chain sizing.

On my 50 ton vessel I had stretched links at the ends, so surely it could have broken in a severe loading situation, but that was easily mitigated by cutting a couple of feet off, not by increasing the size.

If OP has an extra hundred pounds capacity to play with, then increase the anchor weight to something so ridiculously large that even @NomadWillie would be in shock [emoji15]

 

[O C Diver]

I’ve never read a single account on TF about someone’s chain breaking. Not even in a storm.

Considering that chain is generally sized with a 4:1 safety factor in SWL, I honestly believe that most people are ill-advised or suffering from fear tactics when it comes to chain sizing.

One of the advantages of heavier chain is a more gentle ride in lesser winds. It generally takes around 30 knots to straighten my chain out if I'm not anchoring for high winds. As a result, if the chain isn't completely off the seabed when I reach the end of the swing arc, it's a gentle stop not a jerk.

Ted

 

[rslifkin]

One of the advantages of heavier chain is a more gentle ride in lesser winds. It generally takes around 30 knots to straighten my chain out if I'm not anchoring for high winds. As a result, if the chain isn't completely off the seabed when I reach the end of the swing arc, it's a gentle stop not a jerk.

Ted

Sufficient stretch from a snubber will also smooth things out for much less weight. The heavier chain is somewhat of a nice to have, but in my mind, only if you already have a huge anchor and the bigger and heavier chain won't compromise the amount of chain you can carry (or make the boat too bow heavy).

 

[O C Diver]

Sufficient stretch from a snubber will also smooth things out for much less weight. The heavier chain is somewhat of a nice to have, but in my mind, only if you already have a huge anchor and the bigger and heavier chain won't compromise the amount of chain you can carry (or make the boat too bow heavy).

I carry almost 550' of 3/8" G43 chain on 2 rodes. It weighs 775 pounds. The same length and type of chain in 5/16" is 605 pounds. 170 pound difference is meaningless on a 45' 45,000 pound boat. The 60 gallon water tank on the other side of the collision bulkhead from the chain, carries 500 pounds of water.

Already have a 73 pound Rocna.

Ted

 

[rslifkin]

I carry almost 550' of 3/8" G43 chain on 2 rodes. It weighs 775 pounds. The same length and type of chain in 5/16" is 605 pounds. 170 pound difference is meaningless on a 45' 45,000 pound boat. The 60 gallon water tank on the other side of the collision bulkhead from the chain, carries 500 pounds of water.

Already have a 73 pound Rocna.

Ted

The weight difference is a bit bigger for the numbers I've seen. 5/16" G43 is 1.03 lb/ft according to Acco, so 550 feet would be 570 lbs. 3/8" G43 lists at 1.49 lb/ft, so 550 feet is 820 lbs. That's a 250 lb difference, which is not insignificant on a lot of boats. On some boats the issue isn't weight, but the size of the locker and that the larger chain may fill the locker too close to the top and not feed in nicely from the windlass. Or it just may not fit, forcing a reduced amount of chain to be carried.

Boats with a lot of rake to the stem (like mine) will be more sensitive to chain weight, as they're likely to carry more of (or all of) their chain weight forward of the waterline (which produces a larger effect on trim). In my case, the entire chain locker is forward of the waterline and there's not a particularly good solution to that (the bulkhead that ends the chain locker is pretty much where the waterline ends). Volume below the waterline and how other heavy stuff is distributed also have a big effect on how much weight can reasonably be carried that far forward.

As the boat gets heavier and the waterline gets longer, chain weight rapidly becomes a smaller concern. On my boat (38' LOD, 33.5' LWL, a bit over 27k lbs loaded) it carries weight well enough up forward, but by the time I drop my current 73 lb anchor and 90 feet (~93 lbs) of chain off the bow there's a detectable change in trim. Adding more chain is in the plans regardless, but I'll have to move some other equipment (such as the house batteries) to make up for it (fortunately some stuff can easily be moved a few feet aft to put it closer to the boat's longitudinal center of gravity).

 

[twistedtree]

I'm not sure anyone asked if your existing 5/16 chain is G4, or BBB? G4 is stronger.


Personally I'd keep the same chain size, assuming it's G4) to avoid having to change the chain wheel. As others have pointed out 5/16" is fine for your application. And I would stick with 300' as well. You won't need that much along most of the east coast, but it's better to have it and not need it vs the other way around. Plus the extra length will let you cut off the most worn 20' or so in the future and not end up short-chained.


The weight issue, I think is way over blown. It's just not that big a difference.

 

[Benthic2]

If I had all chain I would keep a pair of bolt cutters in my anchor locker.

If you are already own some cordless tools, you can probably get a cordless one. I know Milwaukee, Dewalt and Ryobi all have cordless bolt cutters, so I asume the other brands do as well. Although, since you wouldn't be cutting your chain unless things were critical, maybe a manual one is better ? I guess it depends on the strength of your weakest crew member.

 

[O C Diver]

If I had all chain I would keep a pair of bolt cutters in my anchor locker.

If you are already own some cordless tools, you can probably get a cordless one. I know Milwaukee, Dewalt and Ryobi all have cordless bolt cutters, so I asume the other brands do as well. Although, since you wouldn't be cutting your chain unless things were critical, maybe a manual one is better ? I guess it depends on the strength of your weakest crew member.

A Dremel tool with a 1.5" fiber cutting wheel will cut through 3/8" chain in link in about 15 seconds. 2 cuts is well under a minute. They make cordless models if you don't want to plug an extension cord into the inverter.

Ted

 

[Hippocampus]

View ground tackle as a major safety device. Think limits are how much weight can the windlass pick up. If you’re anchored in 30’ of water then the weight is 30’ of chain plus the weight of the anchor. Unless you change the windlass that’s your limit on a perfect day with the chain up and down. Unfortunately days aren’t perfect. Even if you’re careful using the engine not the windlass to move the boat if there’s a good chop the windlass sees more force. Same if the anchor is well buried or hung up. We don’t try to retrieve then but rather use the engine. Still the windlass is seeing more resistance than just chain weight. So windlass capability is the first determinant.
Second is desired length. Any weight in the bows negatively affects gyradius. Just like any weight in the stern. All boats rise better and faster with a better gyradius. Sail/power or boat /ships it doesn’t matter. Some sailboats (Boreal for one) move the chain locker well aft so its not even in the bow. Less weight up there is desirable. But this is more of a concern for “A” boats not “B” as B boats are less likely to see large seas.
Like you mostly anchor in 10-20’ now. In those settings even as little as 100’ would give close to 10 to 1 as you need some to hit the water and for snubbers. However on several occasions have used all the chain available. Once when a crew broke their arm and conditions required two people to run the boat and I felt he needed immediate attention. I dropped all the chain and drifted until it hooked up.
Second when there was weather coming in and all anchorages with reasonable range were (assumed) to be full. All we checked were full so picked a place protected but deep.
Third when an unoccupied boat looked like it was going to hit us. Wind had shifted and he had dragged. Fortunately he reset. He missed us as we were able to let out enough rode. Owner came back the next day and retrieved his chain and anchor and left with no harm done. Can offer other occasions but you get the idea.
So think for most of us too much is better than too little. You just never know when it’s needed. I’m struck how in Europe boats are spec’d with much less than I’m used to seeing here. Maybe their depths are less or bottoms are better. Don’t know. Do see boats that only use marinas and have ridiculous ground tackle.
But for US east coast think ~250’ is a reasonable length . In the Caribbean had 250’ and often wished I had at least 300’ as the centers of the bays are deep. Would prefer G4 from a NA or European manufacturer as galvi from some Chinese companies is subpar. Would look at scuttlebutt on the manufacturer as an important determinant.

BTW I’m a big fan of all chain. But that’s drift I wish to avoid. Thanks

 

[guy with a boat]

If I had all chain I would keep a pair of bolt cutters in my anchor locker.

If you are already own some cordless tools, you can probably get a cordless one. I know Milwaukee, Dewalt and Ryobi all have cordless bolt cutters, so I asume the other brands do as well. Although, since you wouldn't be cutting your chain unless things were critical, maybe a manual one is better ? I guess it depends on the strength of your weakest crew member.

Best practice with all chain is to secure it to the boat attachment point with a section of line long enough the be accessible up on deck. If necessary to leave your ground tackle behind, cut that line and attach a fender with more line to your chain. Then hopefully return later and retreive it all and you can preserve the full length of chain.

 

[mdresdner]

Storage capacity

Hello everyone.
We are purchasing a Selene 40 (51,000 pounds )and are planning to replace the anchor chain. Currently it has 300 feet of 5/16th. We are planning to replace that with 3/8th HT.
My question is how many feet of chain do I really need to buy?
We enjoy being out on anchor and did so many times with our previous boat. It was 44 Sundeck Motor yacht with only 125 feet of chain. We completed the loop with that boat and only once were not equipped to anchor.
We will be spending the bulk of our travels on the east coast NJ to Florida plus Bahamas.
Do we need to replace the existing 300 feet of 5/16th with 300 feet 3/8. ?

Thank you.
Probably many more questions ahead !
Gabi and John.

I’m not sure the amount of anchor chain you need, but you should consider whether your chain locker can accommodate the larger size 3/8 chain at the amount that you choose to select.

 

[SteveK]

Doc Molar is out shopping for chain Last Activity: 10-15-2023 04:21 PM

 

[PierreR]

Better check your specs on your boat. I think your boat is closer to 41,000 lb and 5/16" is plenty.