Which size and type of chain?

[No Ice]

Can you all help?
I have a Grand Banks 42 loaded it weighs approx 50,000 lbs max.
Im buying a new 40 KG anchor a Rocna but i dont want to get involved in a deep debate on anchor types! I dont like causing trouble

i have 320ft of 10mm galvanised chain but suspect that it will be a bit light for the new anchor.
My anchor locker can hold more but not to much.

All input gratefully received.

Brian

No Ice

[RainDog]

Rocna recommends 11mm G40 or 8mm G70 for your anchor: Chain (Rocna Knowledge Base)

[rocksculpter]

I'd say it depends a lot on the windlass gypsy. What do you have? BBB or high test are different. It would be costly to change out, if you can get one.

Not much difference in 10mm, 3/8 or 11 mm.

[sailorboy1]

You don't really hear of chains breaking. If the chain you have was good enough before it is good enough now. The only thing anchor size and chain size really have together is whether you will need 2 different size shackles to connect them due to thickness (my anchor is too big for the chain so I have 2 shackles to connect).


PS- I think you anchor is too small!

[Cheechako]

Sounds like a lot of weight and windage for 10mm chain. But something is going to be the weak link. using a nylon snubber will reduce the shock loading. You might want to have a soft backup rode like 3/4" or larger. You'll probably be OK 95% of the time with that chain if it's BBB or G4.

[No Ice]

Originally Posted by RainDog

Rocna recommends 11mm G40 or 8mm G70 for your anchor: Chain (Rocna Knowledge Base)

Thanks RainDog, a lot of good reading, i will learn a lot from this. Maybe i can keep 10mm chin size but use G70 chain so i will have enough space in the chain locker.

[No Ice]

My windlass is a Tiger 1200 and i dont know the quality of chain i have only that its galvanised and 10mm

[No Ice]

Sailorboy. why do you say the Rocna 40 KG is to light for my boat, when you look at Rocnas sizing chart i think Im going over the top. My old anchor is a Bruce 30KG and the anchor my boat was supplied with was a 45lbs CQR, now that was to small.
Does anyone else think my anchor size at 40KG is to light for a Grand Banks 42 weighing 50,000 lbs fully loaded? putting a 55KG anchor on may be to large an anchor to fit in the space available.

[sailorboy1]

Originally Posted by No Ice

Sailorboy. why do you say the Rocna 40 KG is to light for my boat, when you look at Rocnas sizing chart i think Im going over the top. My old anchor is a Bruce 30KG and the anchor my boat was supplied with was a 45lbs CQR, now that was to small.
Does anyone else think my anchor size at 40KG is to light for a Grand Banks 42 weighing 50,000 lbs fully loaded? putting a 55KG anchor on may be to large an anchor to fit in the space available.

I just do. I have a a 30kg new generation anchor on my 20,000 lb boat.

But if you have been OK with the 30KG Bruce the 40KG Rocna should be just fine. Just as if your boat hasn't broken your chain with the smaller anchor it most likely isn't going to with new one.


If the above is true and you can only fit the 40KG anchor, that's what I would get.

[noelex 77]

Chain rarely breaks, but 10mm G3, or G4 is on the light side for your sized boat. I would certainly regularly inspect it for corrosion and also elongation.

10mm G7 chain gives you quite a bit more reserve. It is difficult to get, but it will fit your gypsy (providing you get the same type of 10mm chain) and you will have no added weight. This would be my preferred option for your situation.

The alternative is 12mm G4 chain. This has considerable extra weight (and volume which will reduce your windlass drop distance) and you will need a new gypsy. With your boat the weight in the bow will not have a big impact, but check the windlass will cope with the load.

10mm G4 chain is about 2.2 kg/m with a working load of 1250kg
10mm G7 chain is about 2.2 kg/m with a working load of 2200kg
12mm G4 chain is about 3.8 kg/m with a working load of 2120kg

So 12 mm chain will add about 150kg (330lb)

[JonJo]

American, or Imperial, BBB, G3, G43 and G7 chain are all different sized links, G7 is 'similar; to G43 but still different. European chain is metric of 2 specifications ISO and Din (they are only different in link size in the 10mm sizing).

There are 2 anchor chain suppliers in America, their link sizes do vary, again check. 1st China, Defender and West Marine are all obvious sources but any lifting gear distributor will know more about chain (and how to get it) than any chandler.

If you change chain type, say from BBB to G43, but stick to the same size it is very possible the new chain will not fit the gypsy that was compatible with the old chain. Check first, get a 1m length of the new chain and try it or take your gypsy when you buy the new chain. Its going to be expensive if you get it wrong.

Some, many, suppliers of Chinese chain are excellent (Peerless and CMP market Chinese chain) - just buy it from a reputable supplier. Some suppliers of Chinese chain are supplying rubbish. If the supplier is selling something 'unbranded' its for fencing not anchoring.

Why anyone thinks G7 chain is difficult to buy needs to check. Gal G7 chain is 'easy' to buy all you need is money but as you would normally buy a 'smaller' sized G7 link to a G3 or G43 link the price differences do level a bit. As you would then need a new gypsy the overall investment rises. You can buy it freely from West Marine who seem to have stores in every city in America, well almost (gal G7 is made specially for them), its branded as ACCO, to imperial sizes and from Maggi in Italy to metric sizes. Maggi deliver into the Caribbean and have a distributor in NZ who also covers Oz (Chains Ropes and Anchors - or on this forum GMac.). Maggi is freely available in Europe, in the UK Jimmy Green. There are no reports of any issues with G7 chain except that it should not be re-galvanised.

Jonathan

[JonJo]

Do not be beguiled, or misled (even) into thinking HT or G43 chain is ever so much better than G3 or BBB chain. Its Working Load Limit is based on a 3:1 safety factor (possibly because historically it was a Transport Chain) whereas G3 chain WLL is based on a 4:1 safety factor. There is not one iota of evidence to suggest G43 is any safer than G3 chain and you would be better looking at the min Break Strength for a true comparison. You will find that some G43 suppliers only quote WLL - I wonder why.

Another factor to consider is that sizes are nominal and that 5/16th inch chain of one quality might actually be slightly thinner that a 5/16th inch of another quality. The thicker wire size will give a better performance 9and heavier chain). So it merits checking the actual size specification rather than relying on the nominal size.

It merits emphasis that G3 or BBB chain, which has been for sale for a long, long time, has minimal reconrd of failure - which raises the question why the need to buy HT chain - of the same size? If BBB or G3 is perfectly safe - do people have too much money?

jonathan

[HopCar]

"You will find that some G43 suppliers only quote WLL - I wonder why."
That's interesting. I checked the ACCO chain specs and you're right, they don't publish a breaking strength.

"There is not one iota of evidence to suggest G43 is any safer than G3 chain and you would be better looking at the min Break Strength for a true comparison."

I used your safe working load ratios for both G43 and G30 chain and according to your ratios, G43 is actually significantly stronger than G30.

Here is the math using 1/4" chain.

G30 WWL 1300 lbs X 4 = 5200 lbs Calculated Breaking Load
G43 WWL 2600 lbs X 3 = 7800 lbs Calculated Breaking Load


"It merits emphasis that G3 or BBB chain, which has been for sale for a long, long time, has minimal reconrd of failure - which raises the question why the need to buy HT chain - of the same size?"

You don't need to buy the same size, you can often buy a smaller size G43, have the same strength as a larger size G3 or BBB and save significant weight.

As an example, again using your ratio of 4:1 to calculate the breaking strength,
5/16 G3 has a breaking strength of 7600 lbs and it weighs about 112 pounds per 100 feet. BBB actually weighs a little more than G3 because of the shorter links.

1/4" G43 has a breaking strength 200 lbs more than 5/16 G3 and only weighs about 74 pounds per hundred feet. In fact you might even save a couple of bucks by buying G43 instead of the larger G30.

[JonJo]

Thanks Hopcar,

You simply illustrate that G43 is often quoted as being 'twice as good' as G3, or BBB - bacause vendors tend to quote WLL (and quietly ignore min breaking strength). The reality is - as you quote not quite so significant. In fact the difference is simply a reflection of the steel used min 300 MPa vs min 430 MPa.

Frankly it seems daft to reduce chain size from whatever you had for G3 (or BBB) so as to use a lighter G43 - if you want to use your existing windlass as the cost of the new gypsy would be 'extortionate' in terms of the weight saving.

Just out of interest, your 1/4 inch G43 with a approx 4t breaking strength - can you buy gal HT shackles to match and fit? Or do you need to have bigger links welded on?

If you start off with a new windlass and want to down grade chain size (and are thus not an ardent 'catenary' fan) then moving to G7 seems a much more significant option (matching shackles being an issue).

Jonathan

[noelex 77]

Originally Posted by JonJo

Why anyone thinks G7 chain is difficult to buy needs to check.

Well, there is theory and there is practice

The OP is in Italy that produces some great chain including the G7 Maggi metric chain sold at West Marine.
But unfortunately having ordered some from Maggi I can attest the wait for this G7 chain is about 3 months from ordering to delivery. I was warned of the same wait by person that recommended it. (On CF)

G7 is better with some larger links welded on the end which complicates the buying process, demanding that the length is custom made. (Depending what shackles/swivels you can get, or intend to use). G7 does have a significantly higher breaking strain, but unfortunately it's not as easy as getting someone to cut off a suitable length of G3 from their stock.

All this talk of imperial chain is complicating the OP's question. The OP did state 10mm chain. Not 3/8.

10mm chain used on boats with windlasses is invariably one of only two types. Often called Din and ISO (but be careful some manufacturers call them both DIN, but with different link sizes).

Both DIN and ISO are available in the different strengths. G3, G4, G5 and G7. The size of the links, or the required gypsy, does not change between different grades of strength/hardness

The OP can swap between G3 and G7 without any gypsy incompatibility.