Modifying Anchor Shackles

[noelex 77]

The standard D or Bow shackles used on anchors are quite wide and the head of the pin has a nasty habit of catching on some part of the bow roller fitting, or furling mechanism etc as the anchor is retrieved.

There are some special less bulky shackles, but they are hard to find.

There is a simple modification that can be done that involves drilling a small hole close to the body of the pin so the shackle can still be moused and then cutting off the head of the pin. I did one today and took some photos. Although it is very easy they say a photo is worth a 1000 words.

Instructions:
The Monel sizing wire I use is 0.8 mm in diameter so I drill a 2mm hole which allows for a couple of passes of the wire. Drill the hole as shown as far from the end as possible.
I then usually countersink the hole slightly which helps protect the sizing wire by recessing it slightly.
Cut the head of the pin off as shown.
File the edges smooth.
Paint the exposed metal

The only equipment needed is a 2mm drill bit (the cobalt ones are great) and a hacksaw and file.
You can use a small angle grinder if you prefer instead of the hacksaw and file.

Just enough of the pin sticks out so that it can be tightened and loosened by gripping the head with some multi grips or an adjustable spanner.

An alternative is to forget about the mousing hole and use locktight on the threads or burr the end of the pin over with a hammer and punch. You can cut off the head completely with these options if you don't want to remove the shackle in the future.

Disclaimer:
Cotemar does exactly the same thing it's quite possible he posted about this many years ago and gave me the idea.

[JonJo]

One should not really use a 'D' shackle on the anchor (at all) - it does not allow full articulation of the shackle and the shackle can then be stressed in a manner not supported by the shackle make. The shackle maker load specification is on the basis of a straight line pull - which might not occur with a 'D' shackle at an angle to the shank.

Decent bow shackles are as available as 'D' shackles, maybe more so

Bow shackles are common lifting shackles and are thus higher rated than many 'D' shackles and as shackles for lifting are commonly available from a whole host of manufacturers with integrity it is actually easier to buy a HT, or G8, gal bow shackle - than 'D' shackle. You might need to step outside your comfort zone and buy from a lifting specialist - but they are there.

Lifting bow shackles also have short pins, reducing the load on the pin, which also better 'centres' the chain - it has a shorter distance 'side to side'

I'm sure I will be corrected - but lifting bow shackles are the way to go.

So, HT bow shackles are easy to buy, they are cheap, they are better suited as the direct attachment to the anchor shank - and they can easily and cheaply be bought with a strength greater than that of G43 chain (so greater than G4 or G30/BBB) and they, one shackle, will fit the chain and most anchors (not drop forged CQRs - which come with a shackle forged into the shank - or Danforths)

Virtually all of these commonly available HT, G8, bow shackles have a 'lug' extending from the pin - to allow the pin to be removed. This is the problem Noelex wants to address.

Manufacturers supplying only shackles, and other attachments, such as Crosby - there are others - offer shackles in a whole host of imaginative designs and it merits looking at their portfolios prior to attacking your shackle with an angle grinder. If you insist on a 'D' shackle then some, for example Witchard, offer a rather nice 'D' shackle with a recessed pin - they can be strong (but stainless) and will prove a very smooth 'entry'. Being a 'D' shackle they will not articulate in the hole in your anchor shank (or not nearly as well as a bow shackle). Oddly - some manufacturers call their bow shackles 'anchor' shackles (one has to wonder why) even though they are made for lifting.

Noelex suggestion offers a mechanism to remove the lug and still secure the pin - but the widht of the 'bow' of the shackle remains the same so cutting the lug off does little to easy the retrieval (it just moves the problem to the 'width' of the bow) - and makes it difficult to remove the pin. If you only have one bow roller you might want to swap anchors - more difficult once you have cut the lug off (in the dark, rain etc etc.)

Also cutting the lug off and painting the fresh metal is not really a sensible answer - the paint will last a few days (you could paint it again) but then it will last a few hours.

An alternative suggestion might be to alter the roller itself, not the whole assembly, but just the roller. Commonly they are some form of polymer, alter the geometry and you will remove the problem and not sacrifice the integrity nor disadvantage your ease of use of your shackle.

If your shackle somehow fouls your furler - the mind boggles?, then you have a serious issue that cutting a lug off is unlikely to remove.

Jonathan

I think Vyv Cox, consultant to Yachting Monthly, might have detail on use of Loctite on his website, google Cox Engineering. Or go to YBW and try a search on their forum (he mentioned use of Loctite for shackle pin securement over the last 8 weeks or so).

[conachair]

Originally Posted by JonJo

One should not really use a 'D' shackle on the anchor (at all) - it does not allow full articulation of the shackle and the shackle can then be stressed in a manner not supported by the shackle make. The shackle maker load specification is on the basis of a straight line pull - which might not occur with a 'D' shackle at an angle to the shank.

I think you're mistaken on 2 counts there, Crosby DEE'S allow for bridling, check the 45deg marks same as their bow chuckles.

Also, if a single load on a shackle isn't straight line then that's really not a good thing , the 45deg marks are to indicate the maximum permitted angle for 2 x bridle legs coming off a single shackle.
The degree of articulation will depend on the anchor and shackle, but as long as the pin is in the chain it's quite possible for both a dee and bow to be no different in that respect. I use a dee in a Rocna and it's fine.

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[noelex 77]

Originally Posted by JonJo

I'm sure I will be corrected - but lifting bow shackles are the way to go.

I agree. I prefer a bow shackle. It was a lifting rated bow shackle that received the "surgery" yesterday.

Some anchor manufactures insist you use a D shackle with some of their designs, not that I mentioning any names

[JonJo]

Originally Posted by conachair

I think you're mistaken on 2 counts there, Crosby DEE'S allow for bridling, check the 45deg marks same as their bow chuckles.

Also, if a single load on a shackle isn't straight line then that's really not a good thing , the 45deg marks are to indicate the maximum permitted angle for 2 x bridle legs coming off a single shackle.
The degree of articulation will depend on the anchor and shackle, but as long as the pin is in the chain it's quite possible for both a dee and bow to be no different in that respect. I use a dee in a Rocna and it's fine.

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A 'D' shackle can be loaded at 90 degrees when used in an anchor shank - this is less likely, but anything is possible - its a boat, with a bow shackle - which is why both Noelex and I (of apparently different 'backgrounds') would prefer them, lifting bow, to the alternative

But if it works for you, go for it. I, for one, will bow (sorry - awful pun) with complete sincerity to your experience. But I do wonder - given that conventional wisdom (but maybe its not commonplace and I'm biased) prefers bows - what prompted you to stick your neck out and buy a 'D' or did you just follow the advise of a well respected and successful anchor maker.

Jonathan

[conachair]

Originally Posted by JonJo

- what prompted you to stick your neck out and buy a 'D' or did you just follow the advise of a well respected and successful anchor maker.

Jonathan

30 years as a Rigger in the entertainment business, I used to buy shackles by the thousand
A dee just worked better with my setup, it's a little narrower so sits better in the bow roller and spending a while with both a bow and a dee articulation was fine with both, one thing about stamped shackles is very occasionally the embossed lettering can stick. Though how many shanks have slots in them so you can get the pin at the chain end?

So no following the herd but real world observations. I wasn't even aware that the herd followed bow's .

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[JonJo]

I'm not sure that the herd cares.

Most modern anchors will take the 'bow' or equivalent for the 'D' through the shank, I've tested the Fortress, Rocna, Spade, Supreme, and Excel and assuming you are carrying the correctly sized anchor for the yacht and assuming you are using the correctly sized chain for the yacht then you can pass the eye of a bow shackle through the slot and fit the chain to the pin.

But shackles of the same rating from different manufacturers are all slightly different in size and some do not fit - but you can usually find one to suit - but it takes effort. Sadly - to be sure you really need to take one link and your anchor along to ensure you get the right fit. Not very easy if you carry a 100lb anchor

Not being an advocate - if you go bigger is better and buy an anchor 2 sizes bigger there might be an issue - and I have not tested this. Maybe you need 2 shackles - a big one to fit the anchor and a smaller one to fit the chain. Not an issue as the smaller one can be G*, or HT, simply cumbersome.

My observations are based at the smaller end of the anchor market - 15kg -30kg - not sure what happens beyond this.

This all falls over if you use stronger chain and down size as the pin size then gets smaller (to fit the chain) and the opening might not then fit the slot (and this is the real issue with advocating G7 chain)

Jonathan

[HappyMdRSailor]

Wow...

Now "shackle pron".... I need to put the binocs down... expand my field.... explore the horizons.....

(Noelex... you set the hook... good practical app info post)

[conachair]

Originally Posted by JonJo

But shackles of the same rating from different manufacturers are all slightly different in size and some do not fit - but you can usually find one to suit - but it takes effort. Sadly - to be sure you really need to take one link and your anchor along to ensure you get the right fit. Not very easy if you carry a 100lb anchor

The Internet is much easier
Data sheets and a drawing of your anchor or vernier gauge. Once upon a time that's part of what I did for a living, awfully embarrassing if you get it wrong and they don't fit.

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[sailorboy1]

I found that all I had to do to keep my shackle for catching on stuff was to have the pin head on the other side of the anchor.

[No Ice]

Question for Conochair.

I see you are in the UK, please let me know where in the UK i can buy the quality shackles you refer to?
Also you say you use a Rocna anchor, which model and what type and size of chain?
Im in the process of buying a Rocna 40KG for my boat a Grand Banks 42 Max weight 52000Lbs i have 10mm Galv chain which i think is G3 grade, what shackle would you suggest i use?

Brian

[JonJo]

No Ice,

You must be a whisky man?

I'm buying Crosby shackles from here, in the UK

Crosby G-209A Galvanised Screw Pin Bow Shackle 2000 kgs WLL - 221.017.450

If you want stainless shackles - ask - they have a second company that deal in stainless.

Jonathan

[colemj]

Why not just use a slothead shackle if you have problems with the standard pins?

Mark

[noelex 77]

Originally Posted by sailorboy1

I found that all I had to do to keep my shackle for catching on stuff was to have the pin head on the other side of the anchor.

Good point

Originally Posted by JonJo

Crosby G-209A Galvanised Screw Pin Bow Shackle 2000 kgs WLL - 221.017.450

Thanks for the link. The prices for the UK look good.

Originally Posted by colemj

Why not just use a slothead shackle if you have problems with the standard pins?

Mark

The problem is that these sort of shackles can be difficult or impossible to get especially in some of the high test G8 versions.

This green pin shackle is the only slightly smoother G8 version I can find and it still has some significant projections that could catch. The concern is that the anchor winch can exert a lot of force (3500lb in my case) and if the shackle does get jammed you can inadvertently break even substantial fittings when retrieving the anchor. Leaving the clutch with a bit of give is good habit to get into especially for the last part of the retrieve, but it's not foolproof.

Does anyone know of a "smoother" G8 shackle.

[JonJo]

[QUOTE=noelex 77;1505913



Thanks for the link. The prices for the UK look good.

[/QUOTE]


Their delivery prices are also good, or better than many others.

Jonathan