Shackles and anchor chain.

[BarryH]

Emptied the chain locker of chain and the manky bit of rope that was in there. Chain was full of crud, limescale and salt. Soaked the chain in a solution of vinegar and water. Came up OK. Ok apart from some sort of split link that joined the chain. Pain in the backside really as now I have 20 mtr length and a 10 mtr length.

I've decided that I'll keep the short length inboard and the longer length outboard and join them with a shackle. Guy in the chandlery said it wasn't a good idea and offered to sell me another 30 mtr length. I can't see a prob myself. Should be ok as long as the shackle is moused. What do you think?

 

[sarabande]

is the shackle one designed especially for joining chain ? An ordinary one can often not 'set' effectively between the two lengths and may then be3come a weak point. I think the Kong chain shackle is the forum's favourite, but a search and read should reveal more.


BTW, that manky piece of rope... There should be a length of rope fastening the inboard end of the chain to a strongpoint below deck, and ending accessibly above deck so that it can be cut through if an emergency so dictates. (sorry if eggs, grandmother, etc, )

 

[Seajet]

I'm probably being dim, but is the short length chain or rope warp ?

I'd demote any line less than 30 metres away from anchoring use, not much good for shore lines rafting up either as it sinks so maybe 'put ashore' to reduce carried weight.

30 metres of nylon warp + the chain already there ( chain at the anchor end and the shackles seized with locking wire to prevent their working loose ) should see you through intentional anchorages; kedges for handy or emergency use is another topic.

Do mark your anchor warp as to distance let out; everyone has their own system, I mark my warp with a band of magic marker every 20', 1 band for 20, 2 for 40 etc; if one tries to mark metres it ends with a million marks, and if I can't tell the difference between 20 & 40 I deserve to go agound or drift !

Anyone anchoring seriously and often which may involve night moves would be well advised to put something tactile on the warp, such as lacings to feel; though a headband torch helps a lot.

There should be a few metres of chain at the anchor end, to avoid chafing the rope warp on rocks etc, and to aid giving a horizontal pull on the anchor to help it keeping hold in strong conditions.

The weight on the warp should help avoid an unpleasant or dangerously anchor unsetting wave induced snatching pull on the anchor too.

 

[BarryH]

30 mtrs of chain, this had the dodgy link in it, and 20 of warp...the manky stuff. Binned the manky stuff and replaced with 20 of good new stuff. I can't see myself lobbing almost 50 mtrs over to anchor. Anchoring is reserved for sunny days relaxing. There could always be the need in a tight situation so I'd rather have it than not.

Have done search for said shackle......didn't know they were called that. You live and learn, can't be a bad thing.....never stop learning!

 

[Babylon]

You want a Crosby chain link - PM Skipper_Stu, who did a bulk purchase, to see if he has any left: http://www.ybw.com/forums/member.php?u=3212

 

[Twister_Ken]

I can't see myself lobbing almost 50 mtrs over to anchor.

You're not likely to sail N Coast of France/Channel Islands then? 10 metre rise of tide calls for a fair bit of rode, even in benign conditions.

 

[VicS]

I dont remember what size Crosby links Stu Davies was buying. Possibly bigger than needed for the chain on a 23 footer.

These are a commonly available type of link

 

[vyv_cox]

I dont remember what size Crosby links Stu Davies was buying. Possibly bigger than needed for the chain on a 23 footer.

These are a commonly available type of link

The Crosby links are designed for hoisting and are as strong as the chain. Stu does them in 8 mm and 10 mm. For lunchtime and fair weather anchoring one of the lesser ones sold by chandlers may well be good enough. But without a windlass a shackle may well do the job, again accepting that it won't be as strong as the chain. The problem then is that two shackles are needed back to back, as the shackle body won't go through a chain link.

 

[DJE]

My chain is in two lengths and I don't have a windlass so it is joined by shackles. I use two shackles back to back with the pins through the end links of the chain. You can use bigger shackles this way as you don't have to pass the body through the chain link and you should be able to use a shackle with a pin diameter the same as the chain link diameter. But finding proper hot dip galvanised shackles can be difficult. Most of the chandlers supply sheridized and call it galvanised. They will be rusty within a year.

 

[Twister_Ken]

Most of the chandlers supply sheridized and call it galvanised.

Dipped in sherry?

 

[Elemental]

The Crosby links are designed for hoisting and are as strong as the chain. Stu does them in 8 mm and 10 mm. For lunchtime and fair weather anchoring one of the lesser ones sold by chandlers may well be good enough. But without a windlass a shackle may well do the job, again accepting that it won't be as strong as the chain.

Just out of interest, has anyone done any testing of the loads exerted by a yacht, at anchor, against her chain. I've anchored in some strong winds (never anything that would be called a gale though - probably F6, gusting F7) and I could just hold the yacht by hanging onto the chain with my hands. This would probably represent a tiny fraction (< 1%) of the max load the chain could handle. I'm just wondering how much compromise using a shackle or one of the lesser chain links would be.

 

[nimbusgb]

Just out of interest, has anyone done any testing of the loads exerted by a yacht, at anchor, against her chain. I've anchored in some strong winds (never anything that would be called a gale though - probably F6, gusting F7) and I could just hold the yacht by hanging onto the chain with my hands. This would probably represent a tiny fraction (< 1%) of the max load the chain could handle. I'm just wondering how much compromise using a shackle or one of the lesser chain links would be.

Interesting http://northpacificresearch.com/downloads/anchor_load_revealed.pdf

 

[noelex]

Just out of interest, has anyone done any testing of the loads exerted by a yacht, at anchor, against her chain. I've anchored in some strong winds (never anything that would be called a gale though - probably F6, gusting F7) and I could just hold the yacht by hanging onto the chain with my hands. This would probably represent a tiny fraction (< 1%) of the max load the chain could handle. I'm just wondering how much compromise using a shackle or one of the lesser chain links would be.

With a 47 foot yacht I cannot hold on to rope with 3 turns around a winch in winds above about 45 knots. 5 turns around the rope gypsy just does it, but it still slips in the gusts even with both hands and full force. The forces go up dramatically as the wind speed increases.

Edit
I see from the table on Vyv's web site that the load is in the order of 1400 kg, that explains why I cannot hold the chain by hanging on!

 

[VicS]

The problem then is that two shackles are needed back to back, as the shackle body won't go through a chain link.

Puzzled by that statement.

We broke the chain on the Berwick some years ago we repaired it with I'm sure a single shackle ( A bow shackle IIRC ) We peened over the end of the thread and cut the eye of the head of the pin.

The shackle will go though an end link. Its a link that is not the end one that it wont go through surely?

 

[BarryH]

Thats what broke after cleaning the chain. Didn't take an awful lot of force either. I've joined the chain with a shackle for now, mouse'd the pin just to be sure. I can't see it being too weak for the area I'm going to sail in. Probably replace the whole lot in a season or so.

 

[VicS]

Thats what broke after cleaning the chain. Didn't take an awful lot of force either. I've joined the chain with a shackle for now, mouse'd the pin just to be sure. I can't see it being too weak for the area I'm going to sail in. Probably replace the whole lot in a season or so.

I suspect a good few people use a shackle.

I vaguely remember getting a joining link tested at work, the type I pictured I think. It was not very strong even when new. That's why we left the shackle that we'd initially put in as a temporary measure. The shackle is still there about 20 years later!

 

[vyv_cox]

Puzzled by that statement.

We broke the chain on the Berwick some years ago we repaired it with I'm sure a single shackle ( A bow shackle IIRC ) We peened over the end of the thread and cut the eye of the head of the pin.

The shackle will go though an end link. Its a link that is not the end one that it wont go through surely?

I was assuming the OP was joining two lengths of chain without larger end rings, as he was replacing a C-link. It is normally only possible to insert the eyes of a shackle one size smaller through the chain, whereas the pin of a shackle one size larger will go through. When I tested a large number of shackles, results all on my website under anchoring, it was broadly the case that an average 10 mm shackle was as strong as 8 mm chain. Many such galvanised shackles were weaker than the chain whereas some stainless ones were stronger.

With C-links many of the ones sold in chandleries are galvanised (or possibly Sherardised) mild steel, made up very easily. In the tensile tests one of these broke at 145 kg. Links by Crosby and Acco broke at 3 tonnes, or more. Stainless steel ones by U-ship and others made 1.5 - 2 tonnes. Again, it's all on my website.

In the FAQ section of my site there is a piece I wrote for YM on the loads applied to the rode during anchoring. Theoretical values, by ABYC for instance, tend to be high whereas some measured values are considerably lower. Prof John Knox has derived equations based on his measured figures.