Problems ??

If you have a problem using the Forum please tell us! Email: IT@barges.org.

BARGES: All about barges and barging - building, buying, maintaining, equipment, handling on the water, etc. (Public)
For technical advice, please include as much detail as possible about the intended use and/or current equipment, e.g. models, types, sizes, use, age of items. Pictures are also useful.

Finding anchor chain to fit our winch - UK suppliers ideally

  • Balliol Fowden
More
02 Nov 2023 14:34 #1 by Balliol Fowden
That certainly looks better but the camera angle isn’t good. As said there are two issues. Firstly the with of the links must allow the chain to sit snug and level in the pockets or recesses. Secondly at least three or four links must be taking the load at the top (load) side of the pockets. Can you not simulate the anchor? Rope your sample chain to the boat in front?

Chain joining links are available but I wouldn’t use them for an anchor chain!

Balliol.

Please Log in to join the conversation.

  • Will Lahr
  • Topic Author
More
02 Nov 2023 14:10 #2 by Will Lahr
I should thank you for your advice Balliol, and I can certainly see the advantage of having enough anchor chain when it's needed -but of course twice as much is double the cost ;).   I also realised the chart I looked at online that gave a channel depth in the 20s was in feet, and looking at the PLA charts it seems they dredge to slightly more than 10m in the fairway up most of the estuary,  so your 12 meters seems spot on.  

I've tried a sample of 12mm chain, photo attached, and this looks a lot more like Colin's photo, with each link sitting nicely in the Gipsy.   So now I can either order a full 60M of the 12mm chain, or get a shorter bit (e.g. 5M) and see if the anchor goes up and down without jumping and jamming.  My understanding is that shackles etc can't go over the gypsy so a short length couldn't be added on to a longer length later, but it would be a cheaper way of finding out about potential jumping or jamming issues later

Please Log in to join the conversation.

  • Balliol Fowden
More
30 Oct 2023 11:07 #3 by Balliol Fowden
Sorry Will. Probably brain fade! I thought I had read that 100 metres was suggested but reading it all again I see I was wrong.

As Peter Smith said the normal recommendation is to run out 3-5 times the max. depth of water, although that will depend upon all sorts of parameters, but you would probably never WANT to be anchoring in deep water, and there is always the old adage "better to anchor in shallow water where the big ships can't get to you" so it could be argued "so what if you drift so long as the anchor bites before you end up on the beach!"

So let's imagine your tidal range of 7 metres, and you don't want to anchor in less than 4 or 5 metres, so allow 12 metres straight up & down.

At a 3X factor you need 36 metres in the water. At a 5X factor you need 60. Then add on the height of the hawse above water and the distance to the securing point for the bitter end, say 4 metres. On that basis 30 metres sounds too little and 60 metres about right bearing in mind that you will probably be fitting heavier chain than the ship really needs. There is no real science to this because there are so many factors (windage, stream strength, holding ground etc.) but perhaps the Dutch are right

Balliol.

Please Log in to join the conversation.

  • Will Lahr
  • Topic Author
More
29 Oct 2023 15:22 #4 by Will Lahr

Balliol Fowden wrote: Incidentally I'm not sure you need 30 metres. The norm for Dutch commercial barges was 60 metres, albeit working in the generally shallow NL inland and estuarial waters, not the ocean. It depends where you think you might be using the anchor, under what potential worst case conditions and on the type and weight of the anchor but for normal inland use I would have thought that 60 was absolutely ample.

Balliol.


I was a bit confused by this Balliol, are you suggesting 30M is a bit short?  Or is 60 a typo?

Please Log in to join the conversation.

  • Will Lahr
  • Topic Author
More
29 Oct 2023 15:21 #5 by Will Lahr
Thanks Peter.  That makes a bit more sense than basing it on boat length!
 

Please Log in to join the conversation.

  • Peter Smith
More
28 Oct 2023 22:54 #6 by Peter Smith
i Will, I think you will find the recommended length is 3 to 5 times the water depth to anchor.
Often it’s the chain on the bottom doing the holding not the anchor. The anchor bights in in severe strain.

Please Log in to join the conversation.

  • Will Lahr
  • Topic Author
More
28 Oct 2023 17:54 #7 by Will Lahr
Thanks for your posts,  with regard to the sizing I've taken another look at Colin's photo of a chain fitting correctly so I now have a better sense of what I'm looking for.   I've got a sample (1 meter again) of 12mm chain coming.  It seems like the in between sizes (between 12 and 16) are a little harder to come by, but I've discovered there's a supplier just over the road, so that might come in handy if the 12 is too small.  

As for the length, my logic is simply to do what the surveyor told me to because the insurance have a copy of the report!  We can't get anywhere without going on the tidal thames from here so the first reason to have one is in case of an engine failure out there.    30m is obviously more than enough to reach the bottom going straight down,  a high tide can be 7 or so meters, below which there can be anything from a negative amount of depth to 20 meters or so in the middle of the fairway - where you're not usually cruising and won't make friends by anchoring anyway! 

When it comes to allowing for angles and things I've yet to find any clear guidance;  multiples of the boat length like 3x and 5x amounts to half a ton of chain for us and seems longer than anyone else carries.  100m of chain stretched across a busy river with a barge on the end also strikes me as potentially problematic.

Please Log in to join the conversation.

  • Colin Stone
More
28 Oct 2023 12:04 #8 by Colin Stone
[ltr]I ended up with 100m of 16mm and 13mm.  I specified 50m each end, but full Exalto DIN 766 100m chain tubs arrived at the builder and it was just fitted.  Makes good ballast though!! 
I've had to remove some from the cable bins, as they were to full for the chain to pile properly, so I could have some surplus to dispose of. I recall about 30m each end but I won't be able to get at it properly and check until we dry dock next year in NL in June and wind it all out. 
We did use a good long length of bow chain while anchored in the Baie de Somme to resist the scouring of the sand in a 5+kt springs tidal stream/tidal bore. [/ltr]

Colin Stone
It's not the destination, it's the glory of the ride.
Barge Register KEI

Please Log in to join the conversation.

  • Balliol Fowden
More
28 Oct 2023 10:31 #9 by Balliol Fowden
Sad to say but it looks as if the links on your sample chain are a little bit on the fat side for the gypsy, also perhaps a bit long. 

In terms of link width the three links that are visible lying "flat" on the gypsy are actually slightly canted as you say, as if they are not quite fitting snugly in the width of the gypsy. If they won't lie flat in the gypsy recesses then they are too wide. 

In terms of link length, whilst the most obvious link is lying snug against the top end of the recess in the gypsy (in the loaded retrieval position if you like) the next link down appears not to be bearing on the gypsy, suggesting the links are a tad too long.     

Colin's chain looks to be a perfect fit to me so could serve as your model, and you can see that the links are sitting flat and at least two of the links seem to be bearing well in the gypsy recesses, presumably under load from the weight of the anchor and the weight of the chain hanging in the chain locker.

The real test is under load. You don't say how long your sample is but is it possible to load it at each end to simulate the weight of the anchor and the weight of the chain hanging down the navel pipe? Perhaps lash water-filled 25 litre drums to each end, one in the chain locker, two outside the hawse pipe, then turn the gypsy over as much as possible for the length of sample and see if the links lie flat and snug in the gypsy? If they remain canted then the links are too wide. If say the three main "biting" links are not evenly weighted on the gypsy then the links are too long or too short.

Is it not possible to "borrow" a longer sample?

Incidentally I'm not sure you need 30 metres. The norm for Dutch commercial barges was 60 metres, albeit working in the generally shallow NL inland and estuarial waters, not the ocean. It depends where you think you might be using the anchor, under what potential worst case conditions and on the type and weight of the anchor but for normal inland use I would have thought that 60 was absolutely ample.

Balliol.

Please Log in to join the conversation.

  • Richard Cooper
More
27 Oct 2023 17:15 #10 by Richard Cooper
Measuring Chain, How to do it (chainsropesandanchors.co.nz)  This is a New Zealand site but it might be helpful. you really need to try a couple of revolution of the gypsy to see if it is fitting otherwise a mm too short per link adds up to a cm somewhere further on and it jumps or it fits so tightly that the chain will not unwrap. On the other hand if its too loose it jumps too. Might be an idea to remove the old chain, compare the number of links per metre etc. with some new chain in the chandlery and see if one sample is half a link or so longer.

Please Log in to join the conversation.

Moderators: Bob MarslandPeter Milne
Time to create page: 0.162 seconds