Linking chain - different gauges/lengths

[Roach1948]

I have three different short lenghts of chain that I want to amalgamate into one useful length. They all are of different gauges but as I dont have a windlass and I lift manually that is no problem. I planning on linking the chain heaviest to lightest (heaviest from the anchor of course). My question is how to make reliable linkages. I was planning on taking to the local ironmonger and having him make some links and then getting the whole length regalvanised - any other ideas?

 

[Mirelle]

Frankly, that's probably the best idea. Proper chain joining shackles have not been made in yot sizes for many years, now.

 

[chrisross]

I would think that it would be quite expensive to do what you propose although it seems to be a sensible technical solution. I would really be interested to know what the total cost would be like compared with purchasing the equivalen length of new chain.

 

[Roach1948]

Yes, I was thinking of the costs too - I will let you know. I think I can do it on a budget though. Being Suffolk there is a ironmonger I know on a local farm and galvanising I dont think is that expensive if you send a large batch off.

 

[DeeGee]

[ QUOTE ]
Frankly, that's probably the best idea. Proper chain joining shackles have not been made in yot sizes for many years, now.

[/ QUOTE ]Umm? Chain links are freely available, and the quoted strength is greater than the equivalent normal chain link. I suppose it depends on what you call 'proper' /forums/images/graemlins/tongue.gif

 

[Anonymous]

Depends really on whether things but look and be 'just so' or whether functionality is the only real issue. If you are only looking for functionality for a boat of your size, you should find that you can (with care) source shackles that are as strong as the weakest chain you are using, and as strong as whatever strong point you are attaching it to. But, most galvanised shackles are really cheap **appy junk - I only buy stainless now but you can get good rated galvanised shackles from Plastimo which you can order specially from your chandler. I would go for decent stainless shackles even on galvanised chain and you have the benefit of being able to unlink the section when you want to as they won't rust solid.

 

[DeeGee]

I was advised not to mix ss and galvanised? These chain links are spec'd to be stronger than the chain links themselves. However, in this case, where the composite chain is not going round a windlass, I suggest using links the same size as the bigger chain. /forums/images/graemlins/smile.gif

 

[Anonymous]

Not mixing ss and galvanised is an accepted wisdom but looking around at all the ss anchor swivels and shackles used by liveaboards and people who anchor for many months per year, there really does not seem to be a problem in practice. I used not to mix but now I am fed up with galvanised - though I will stay with galvanised chain as ss is far to expensive for me.

I have had a couple of ss shackles on my chain for around four months this summer, constantly immersed over that time, and there is no visible degradation. Is there invisible degradation? I don't know.

Aside from the electrolytic issue there is the question about brittleness; ss is more brittle than steel, I believe, so brittle fracture is a possibility. But these things are spec'd way over the strength of the bits on the boat that they are attached to so it probably all becomes academic!

 

[GMac]

Just get someone who knows how to weld properly and cut a link then weld it to the next section. Easy peasy as long as the welder knows thier stuff.

 

[Ships_Cat]

Is no problem with ss shackles in galv anchor chains. Your advisors are probably confused with continually immersed applications such as for moorings.

For those wanting good quality galv shackles then the best source in my experience is from companies that specialise in lifting gear where from one can buy tested shackles (cheaply) - or from GMac but he may be a bit far away for most /forums/images/graemlins/smile.gif.

John

 

[Anonymous]

The galvanised shackles I have been getting in southern Spain over the last 18 months have been terrible. Utterly pointless. They start rusting in days even when just exposed to the sea air! The tiniest nick makes them rust big time which proves that the plating is thin to the point of non-existence as the whole point of galvanised metal is the ability to cope with quite large nicks.

 

[Ships_Cat]

Same here if they are bought from chandlers, etc most just cheap Chinese or similar jobbies and galv goes very, very quickly.

For the tested lifting ones here the galv is ok. But, even so I actually use some untested ss bow shackles I came across - not sure of the actual quality but they are much more heavily constructed in the bow than normal ss or tested galv bow shackles (our anchors are made so that the bow goes through the shank, pin through the chain and pin sized as close fit through the chain link).

John

 

[cliff]

[ QUOTE ]
Aside from the electrolytic issue there is the question about brittleness; ss is more brittle than steel, I believe, so brittle fracture is a possibility.

[/ QUOTE ]Sorry to inform you but you belief is not quite correct - metallurgically speaking.
--------------------

"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[GMac]

95% of all shackles come out of asia now. Most Hi-loads as well. Not the genuine Green Pin though.
Quality control is something they have issues with.
A very large amout of Asian 'hot dip galvanising' is really 'washed zinc plateing' i.e they zinc plate and put it in some stuff so it looks Hot Dipped. Zinc plating is not as good as real HDG.

If you knew the actual WLL on most commercial (the everyday ones everywhere) shackles you would pooh yourself.

We use them but also get some out of Italy specifically not galvanised which we do here. Damn nice but cost only a little more than the shi*ters.

Keep hunting the lowest price and all that will happen is more EU, US and so manufacturers have no choice but to source from Asia. Most big brand names do now anyway. Sad but a fact of the 'global village' we must now live in. Obviously low prices are usually attached to low quality.

As Ships Cat said, Stainless in an anchoring system is fine. In a permanent mooring it is not.. a very big NOT.

 

[Ships_Cat]

GMac - is there any difference between "Red Pin" and "Green Pin" (I think there may be a "Silver Pin" too, but maybe that is just another name for "commercial"?)?

John

 

[GMac]

Green Pin are made by Van Beest in Holland or Belgium (somewhere around there anyway) and the 'genuine' artical. Working load limit is marked on each shackle and has a 6:1 safety margin i.e a 11m pin has a WLL of 1500kg giving a break of 9000kg.

Red, Blue, Yellow, Silver and many other colours are all asian made knock offs. Generally due to the serious nature they are used for the knock offs do seem to be OK. Here you will see yellow pins with PWB (Aussie chain maker) on them = chinese made. Plasimo = chinese made (actually an awful lot of Plasimo gear is chinese made)

If your pushing limits I'd go Green Pin as they are all batch tested, have believable Test Certs and the factory is a Lloyds Approved one as well as BV, GL and many more. They are a class act.

Expect to pay around twice as much for a green pin than any other colour, still not that much though and worth it.

As a rule the word 'commercial' is attached to the everyday stuff. Like the bog standard galv shakcles in most chandleries (worldwide). 'Commercial' give them a better look when the marketers get in on the act. A bit like 'Australian Standard' is fast becoming a code word for Chinese made, in the Sth Pacific anyway. By the way we have chinese made Australian Standard chain and Australian made Australian Standard chain. They are about as similar as a Morrie Minor and a Shumachers F1 car.

 

[Ships_Cat]

Thanks for that GMac.

Just had a browse here on the boat and see I have some yellow pin ones - I think they came from C____kes so must be ok for lifting (rest green pin, from a ship providores).

John

 

[GMac]

That the place with 'roo' in the middle bit. No spelling mistake /forums/images/graemlins/smile.gif

 

[Anonymous]

While in the process of researching the question about the risk of brittle fracture with stainless, I came across this interesting discussion about stainless and corrosion. Like all things on the internet one has to be careful but it sounds OK to me....

From Article about corrosion of stainless steel

Stainless Steel
Because there are so many misconceptions about stainless steel (a misleading term in itself, though not as bad as ‘inox’) it’s probably worth momentarily delving into the technicalities. As well as iron and carbon, stainless steels include a number of alloying elements. Of these the most important is chromium (Cr.). If there is more than 12% in the alloy, a complete layer of chromium oxide surrounds the metal. This layer, the ‘passive’ film, is resistant to most things and will self-repair in the presence of oxygen. Chromium-only stainless steels tend to be brittle, so about half as much nickel (Ni) is added to create a more usable material. 304 stainless (or A2) is one of the more commonly available and includes 18% Cr and 10% Ni. If you have a stainless sink or exhaust pipe it’s likely to be 304 and, as anyone who’s ever tried cleaning a sink or pulpit will know, is somewhat prone to attack from the organic acids generated by food, fingerprints and other pollutants.

The chemical and food industries alleviate these problems by adding a dash of Molybdenum (Mo). Thus 316 stainless (or A4) typically comprises 17% Cr, 11% Ni, 2 % Mo and is widely used to store and transport some very aggressive substances. So, you might think that this is the perfect stuff to use as a fastener in or through wood, and from the sole perspective of chemical attack you’d be right. But we need to reconsider the environment in which the fastener is doing its job. Imagine a bolt, nail or screw fastening a plank to a frame underwater. The head, at or near the surface, will be oxygenated enough to maintain its passive film. The shank, buried deep in the structure, is likely to be starved of oxygen but will be surrounded by various acids and chlorides. In these circumstances, the passive film may break such that the stainless becomes ‘active’. This has two effects: firstly, look back at the galvanic series and you’ll see that the difference between active and passive electropotentials in 304, and to a lesser extent in 316, is enough to cause galvanic corrosion. Like brass, stainless can form its own galvanic couple. Secondly, without the oxide layer, the stainless will corrode about as fast as steel. The upshot is that stainless fasteners below the water-line - irrespective of the grade - may be no better than mild steel. Above the water-line (more oxygen and less electrolyte) such fastenings are fine, but unless you value the extra lustre of 316, there’s little point in paying for it.

While on the subject , I’d like to tackle the nonsense of shot-blasted stainless fittings which seek to ape the appearance of galvanised fittings. The ability of the passive film to self-repair is optimised if the surface of the stainless is highly polished. By forming millions of sharp peaks during shot-blasting, you significantly reduce this ability, which is why such fittings rust. If you want the appearance of galvanised fittings, try galvanised fittings.

 

[Anonymous]

The following is an excerpt from Brion Toss’s book “The Complete Rigger’s Apprentice – Tools and Techniques for Modern and Traditional Rigging” (International Marine; Camden, Maine 1998).

“Obviously it pays to invest in high-quality stainless and to make it plenty heavy, to delay the onset of fatigue. Bronze is nearly impervious to fatigue, which is why it is so often used in toggles, turn-buckles, tangs, and chainplates. Galvanized steel is likewise just about fatigue-proof, so if you can keep it from rusting, it will outlast stainless."