omega chain 2 anchor link

[simonfraser]

Hi

provided it all fits, i can use the black pin through the chain ?

and the red U through the anchor shaft to allow for sideways rotation ?

the small black pins 'just' push in, and locktite those, is that secure enough for anchoring ?

i'd rather not use a crosby lifting shackle as anything protruding is likely to catch on my bow gear at the worst possible moment

Tnx

 

[vyv_cox]

Loctite 242 works very well. No softening underwater, no loss of strength with time.

 

[Neeves]

The opening in the Omega link will almost definitely be too small for your anchor shank unless you are considering an oversized Omega link and an undersized anchor.

The common usage in the rode is to use the Omega with the chain, same size for which the link is specified, in the link and the cotter pin through the link. You then use the Omega as an enlarged link at the end of your chain. You are unlikely to find Omega links galvanised, they are commonly powder coated - so if you go this route buy 2 (they are cheap) use one until you find it too grotty then swap. You could then clean the first link, paint and see as a spare.

We used Omega links on the ends of our HT downsized chain.

The links are made for specific chain, so an 8mm link will accept a 8mm chain link but the slot will be too small for 10mm chain and the pin to big for a 6mm chain. The link in your picture is for 7/8mm chain and is a G80 quality. It should be supplied with hammer in retaining pins. The cotter pin has no retaining feature, other than the retaining pins and, depends on the supplier, tends to be a loose fit. I'd be a bit wary of relying on Loctite

It depends what you are trying to achieve but a hammerlock might be an alternative. We have used them and a number of members here use them instead of a shackle.



Hammerlocks and Omega links come in variety of sizes, 6mm and up and a variety of strengths, G70, 80. 100 and a few 120. Strength is not the issue - fitting is the issue.

This is an example of how we use Omega links. The anchor shank accepts a 3/8th" 2t WLL shackle and the chain is 6mm with a approx 1t WLL (slightly higher than the G30 8mm chain it replaced). There is no way the Omegas, that match and fit with the chain, is going to fit on the shank, which is Bis 80, and 15mm wide. The Boomerang I made and thinned the ends to accept 6mm Omegas and I also had to manicure the slots on the Omegas and gave the slots more meat to cater for the thinning of the slot end. I remove all the powder coating or paint on all my components and have them galvanised.

When I have HT chain galvanised I also ensure the connectors that will match for both strength and fit are galvanised at the same time, the same process, and each rode is supplied complete (excluding the anchor) with spares.



Good Luck

Jonathan

 

[simonfraser]

Tnx Jonathan

The omega gap is indeed too small, just checked on the boat

Have ordered 0.75T Crosby bow shackle, biggest that will fit my chain, matches the SWL of the chain

I’ll loctite 648 the shackle and probably cut the ear of the pin off

S

 

[Martin_J]

If you're careful with the drill, you can still seize them with a monel wire, even with most of the lug cut off..

 

[Martin_J]

Although it might cost you a 1mm drill bit if you're not careful!

 

[Neeves]

An alternative to the little hole, which is a devil to drill with a tiny drill bit and tough HT steel is to cut the pin off flush, but DO NOT CUT OFF THE SHOULDER, and then notch it for a big flat screw driver. In stead of a screw drive a big bit, appropriately sized, bit of HT steel that you convert to a screwdriver. Then use Loctite. If you do drill - do it at home where you can put the shackle into a big vice or the into a vice in a decent bench drill (or buy a set of small drill bits as you are sure to break 1 or 5 or them.

Simon - realise that if your shackles locks up in the anchor slot then the tension on the shackle will be at an angle. If tensioned at 90 degrees the WLL of the shackle is reduced by 50% (and at 45 degrees 25%). I have tested this - its right. I also have a failed shackle that looks to have been side loaded where the pin simply pulled out of the eye as the bow opened. Shackles locking sideways in the slot does happen, not often, but in one case - at least too often.

Ideally you want to use a Crosby 209A shackle - its the one where the 3/8th" shackle has a WLL of 2t but the range does not go down in size, the smallest being the 3/8th" Crosby® 209A Alloy Screw Pin Anchor Shackles | Crosby®

If you know anyone in the US then Peerless make smaller shackles to the same quality as Crosby's 209a in Peerless' "G80 Peerlink" range. But Peerless don't seem to have 'export' in their vocabulary - so they need to be bought there and posted. At the smaller sizes its a real faff getting everything to match such that the lowest SWL is that of the chain and everything else should be better/stronger.

If you can put the Omega onto the end of your rode and then use a bigger, stronger, shackle that still fits the anchor and the omega accepts the pin (which will be too big for the chain) and the bow of the shackle is through the shank slot. If you use an Omega commonly the little pins corrode solid into the little holes and to disassemble you need to drill out the pins and then hammer the clevis pin out with a punch. I bought a set of punches for just this task and when I 'made' rodes I supplied punches with the rode (along with Omegas links + spares, boomerangs etc)

Or use a hammerlock, again you would need a set of punches (any tool shop, they are not particularly expensive - they come, usually, as a set).

Jonathan

 

[simonfraser]

tnx J

'Simon - realise that if your shackles locks up in the anchor slot then the tension on the shackle will be at an angle. If tensioned at 90 degrees the WLL of the shackle is reduced by 50% (and at 45 degrees 25%). I have tested this - its right. I also have a failed shackle that looks to have been side loaded where the pin simply pulled out of the eye as the bow opened. Shackles locking sideways in the slot does happen, not often, but in one case - at least too often. '

yes, that started all of this, setup at the mo is like this




the SS shackle is from S3i SWL 900 kg, you can see there is 'little' sideways play

i have added a 2T Crosby bow shackle to the order, that will sit through the Knox shaft with the 0.75T Crosby bow shackle through the chain

planning to put washers, if needed, on the pin of the 0,75 to keep the chain central, but not on the pin of the 2T
that make sense ?

apreciate it might still 'lock up' but i have to be realistic with the weather and holding ground conditions
east coast UK, mainly mud and some sand, chances of anchor getting stuck at 90' is low
i def leisure motor and park overnight in benign conditions, so the whole setup is over engineered, as it should be

S

 

[Neeves]

Simon - what size and quality G30, 40 - 70?, chain are you using?

Jonathan

 

[boomerangben]

tnx J

'Simon - realise that if your shackles locks up in the anchor slot then the tension on the shackle will be at an angle. If tensioned at 90 degrees the WLL of the shackle is reduced by 50% (and at 45 degrees 25%). I have tested this - its right. I also have a failed shackle that looks to have been side loaded where the pin simply pulled out of the eye as the bow opened. Shackles locking sideways in the slot does happen, not often, but in one case - at least too often. '

yes, that started all of this, setup at the mo is like this

View attachment 175179


the SS shackle is from S3i SWL 900 kg, you can see there is 'little' sideways play

i have added a 2T Crosby bow shackle to the order, that will sit through the Knox shaft with the 0.75T Crosby bow shackle through the chain

planning to put washers, if needed, on the pin of the 0,75 to keep the chain central, but not on the pin of the 2T
that make sense ?

apreciate it might still 'lock up' but i have to be realistic with the weather and holding ground conditions
east coast UK, mainly mud and some sand, chances of anchor getting stuck at 90' is low
i def leisure motor and park overnight in benign conditions, so the whole setup is over engineered, as it should be

S

You are wise to want to change that arrangement. If my maths is right, once you offset the boat by a distance of 2x the water depth (for a 5:1 rode) the cross load through the pin is equal to the tension in the rode. So in other words, the force trying to splay the cheeks of the shackle is equal to the pull in the rode. If the shackle is the other way round, there should be no load trying to spread the shackle cheeks.
This is why as Neeves points out cross loading a shackle is dangerous if not sufficiently over sized.

In an ideal world, shackles should not be side loaded and in the lifting world, they go to great lengths to design out the possibility of this happening as well as having banksmen to make sure all the jewellery is properly aligned before the load goes on.

I’ve never used a hammerlock for anchoring and only ever seen them used to connect chain to master links and hooks, all of which have a circular cross section at point of contact. A hammerlock in an anchor stock doesn’t look right to me and runs the risk of potentially high side loading. Hammerlocks are not designed for that although anchoring loads in all but survival conditions are so low it doesn’t seem to matter.

So the goal has to be to use a bow shackle through the the anchor shank with the pin through the last link in the chain. Omega link if required but the less bits of jewellery, the less there is to go wrong. If you can manage against a shackle getting bound in the shank, then you don’t need a shackle to be any stronger than perhaps 20% of the chain WLL. I am trying to imagine how a shackle becomes bound in the shank. This would either happen when there is limited clearance (so don’t make the shackle too big) or the shackle starts to rotated in the shank (the pin and cheeks get bound in the slot). In the latter case I would imagine that removing the end of the shackle pin might even increase the chance of binding. I can’t help feeling that a bolt type shackle would maybe prevent binding because there is less chance of it rotating through the slot in the shank. However my practical experience here is very limited

Edit to say my numbers are based on using a 3/4te Crosby Bow shackle in a Fortress FX7 shank. I have 6mm chain so in fact would only use a 0.5te shackle. Hopefully I will be able to pop into the local shackle shop tomorrow and get a couple of each size to experiment with!

Edit again

Regarding binding. Perhaps the real cause of binding is the slot in the shank. The slot is only required to get a bow shackle properly installed, there after at least half of it is redundant until you come to need remove the shackle. Perhaps some form of filler is needed to help stop binding

 

[simonfraser]

Simon - what size and quality G30, 40 - 70?, chain are you using?

Jonathan

full 8mm came with the boat, now 7m of 8mm and a lot of nylon, don't know re Gx

i had full 6mm with a slightly larger / heavier boat - that was from a UK supplier 5 yrs ago

 

[simonfraser]

'bolt type shackle' protrudes more, especially on the split pin side
that is going to catch on my bow gear

 

[boomerangben]

'bolt type shackle' protrudes more, especially on the split pin side
that is going to catch on my bow gear

Perhaps then the 2te shackle with an Omega link rather than the 0.75te shackle to connect to the chain? The Crosby 6mm Omega link (they call it a coupler) should fit.
Edit. Ooopps missed the fact it’s 8mm chain not 6mm. Still should work with an 8mm link

 

[boomerangben]

'bolt type shackle' protrudes more, especially on the split pin side
that is going to catch on my bow gear

And the 2te screw pin is wider than the 3/4te bolt type so if you can get a 2te screw pin over the roller, could a 3/4te bolt type not fit?