Stainless steel anchor chain

[Deleted User YDKXO]

The weight of chain on the seabed is not an advantage. When the wind picks up to only moderate winds, say 15kt then all the chain is off the seabed anyway. The anchor needs to hold the boat in a blow, maybe an unexpected one and in a blow the chain is straight, so chain on the seabed does nothing and even the much touted catenary does virtually nothing to help.

Nah disagree with that. I have snorkeled out to inspect my anchor many times in the Med and I am always surprised by how much of the chain is still on the seabed and how little it moves even in windy conditions and the boat shearing about above. If all of the chain is lifted off the seabed then you are probably in trouble because no anchor, however good it is, is going to develop its max holding power for the given seabed conditions if there is a vertical component of the load pulling it upwards

Of course it does matter how much chain you put out. In 15kt of wind I will try to put out at least 5 x depth of chain or more if possible, particularly if we are staying overnight or planning to go ashore

Btw just to drift the thread a bit has anyone got a good recommendation for a remote anchor watch ie a system which will send an alarm to your mobile whilst you are ashore if your boat moves outside a certain radius?

 

[runningman]

Btw just to drift the thread a bit has anyone got a good recommendation for a remote anchor watch ie a system which will send an alarm to your mobile whilst you are ashore if your boat moves outside a certain radius?

Yes. Anchor Pro (Android app) is what I use. Leave one phone on the boat with app activated and carry your main phone with you. Text message is sent if boat moves outside preset radius.

Edit. Following this thread as I have SS chain and anchor!

 

[BartW]

This is the P68 anchor chain locker with 60m of 10mm chain. We will be replacing it with 80m of 12mm chain.

if you do the upgrade, I would go for at least 100m !
(if it was for me, than 130m as explained in a previous post)

 

[BartW]

Nah disagree with that. I have snorkeled out to inspect my anchor many times in the Med and I am always surprised by how much of the chain is still on the seabed and how little it moves even in windy conditions and the boat shearing about above. If all of the chain is lifted off the seabed then you are probably in trouble because no anchor, however good it is, is going to develop its max holding power for the given seabed conditions if there is a vertical component of the load pulling it upwards

Of course it does matter how much chain you put out. In 15kt of wind I will try to put out at least 5 x depth of chain or more if possible, particularly if we are staying overnight or planning to go ashore

++1

for the remote anker watch, we use our crew / cooking lady ;-)
(no idea really)

 

[Magnum]

if you do the upgrade, I would go for at least 100m !
(if it was for me, than 130m as explained in a previous post)

We had 100m on our sailing boat and with a 3m draught always anchored on 5-12m of water. We never used the full 100m so its difficult to imagine we will do so in the 68 when anchored in slightly shallower water.

 

[Magnum]

After careful deliberation and in light of the photos showing the P68's anchor chain locker received today, I've decided to go for 12mm galv not s/s.

I'm very grateful to all those who commented in this thread

 

[Portofino]

Once left the kids on board aged 14 and 11 in clam anchorage while wife and I went foraging for supplies .Had to walk a bit inland -short cut to town .
It blowed up and started to drag -eldest was schooled in start up and bug out .Thing is all the boats started to swing about -stretch catenary etc or drag .
They were heading for a Managusta 130 ,but there crew started to fender up and deploy tender to help .
But kids managed to start up -up anchor and the day was saved .
We saw it all unfold as we sighted the bay .
Up shot of this experiance -the point to Mike F,s quote above ----
Is check out your insurance --re small print about leaving the boat @ anchor and cover ?
My broker had to ask the underwriters -cos there's nowt specific in the T +C policy wording .
Any how I have it in writing -along the words of

"Keep a line of sight of the boat and never be more than 30 mins away to get back

So if plan on leaving it unattended @ anchor ---will you still be covered ?

 

[Portofino]

After careful deliberation and in light of the photos showing the P68's anchor chain locker received today, I've decided to go for 12mm galv not s/s.

I'm very grateful to all those who commented in this thread

I think that will work v well
Fast winch
Big locker
The one sided slope actually helps prevent stacking -first X M will slide away from where it's coming in

 

[Neeves]

The idea that when the wind gets up and your chain lifts off the seabed results in an anchor having a pull above the horizontal is only part correct. If you have a decent modern anchor and you power set, or the wind has power set your anchor, then the anchor will be submerged into the seabed. In fact if you have anywhere near decent an anchor you simply will not see it. The anchor and chain will have neatly buried itself into the seabed. When good modern anchors set the fluke toe and shackle are the first to disappear. Not so many of the old fashioned types, it is very difficult to get them to bury.

A buried anchor takes chain with it and the chain resists burying, it has surface area. As the chain buries it develops reverse catenary, and the shackle, which is the load point to the anchor, lifts within the seabed (its being pulled up by the chain). This happens whether your chain is on the seabed or all lifted.

The angle of the shackle, the angle of pull on the anchor, is independent of the angle the chain had at the seabed. The shackle angle is determined by the amount of chain buried and resistance of the seabed.

So forget the old fashioned idea that you must have chain on the seabed - its rubbish (or - so as not to antagonise - not the panacea suggested). If you have a modern anchor - bury it. Its providing you hold and good hold because its well buried. By all means have chain on the seabed - if you have all that heavy chain use the old fashioned concept of catenary. If you are in a shallowish, say upto 7m, and tight anchorage you will not, possibly, be able to deploy 60m of chain - don't worry - a good anchor, correctly sized, will hold you.

If the seabed is very hard - go back to the old concept, chain on seabed means best tension angle - but most recognised anchorages allow anchors to bury.

In addition if the chain is buried then any twitching of the vessel will be dampened by the buried chain - that twitching, yawing, hobby horsing, will have less effect the more chain you can bury.

And I hate to say this but you can bury more thin chain than thick chain, swivels resist diving (because they are large in relation to either shackle or chain).

Most modern anchors bury, as I describe, toe and shackle first, Rocna, Supreme, Kobra, Ultra, Spade, Excel, SARCA - some do not (and are therefore questionable). Fortress and Danforth are exceptions - the shackle is the last part of the anchor to disappear - they are not questionable, get them to set and they will dig deep forever.


The image of the chain locker - I assume there is a drain hole at the bottom. The locker needs to be emptied fairly regularly and the locker washed clean - the drain hole can, easily, block and you will collect a puddle of seawater which will do chain no good. On a calm day, deploy the lot and wash out. When the vessel has AF conducted, take all the chain out, wash locker and chain with fresh water. That's a deep locker - with time you will have no idea what is going on down there!

Edit: I'd be inclined to consider having some sort of false bottom on that locker so that if water collects it is not filled with wet chain and the chain can then dry. I cannot think of anything quickly - we have perforated mats on the bottom of our, flat, locker - the chain can drain. maybe add some chopped up mat in the more normal pyramidical locker. close edit.

 

[Magnum]

I think I said earlier in this thread that we have upgraded the anchor to a 60KG Ultra. The recommended chain size for this anchor is 12-13mm.

http://www.ultraanchors.com/images/PDF/UltraAnchorSelection.pdf

 

[MapisM]

When good modern anchors set the fluke toe and shackle are the first to disappear.
Not so many of the old fashioned types, it is very difficult to get them to bury.

Blimey, by this rate I will think that my old tub was already at the forefront of boating technology, when she was built 20 years ago.
First, with galvanized being better than s/steel, and now with Union anchors, which I always considered old fashioned but are instead modern, as I understand...

 

[Zing]

I've got to challenge the assumption behind this, that a low angle pull is important. In low winds any old lump of metal with a string leading to the boat will hold. As the wind picks up you might need an engine block on some rope to hold, noting matters much, but when the wind is strong, 25kt upwards you need to have a good anchor properly dug in and the chain will pull up, almost straight to the bow and even with a 5:1 scope there will be negligible catenary. So why bother trying to achieve a horizontal pull, as when you need it most you cannot achieve it.

It is also not necessary to try achieve the max holding power of the anchor. Of course it is true that an anchor will nor achieve its max holding power with an upward component, but they are actually designed for this and do work very well at the 70% say of max holding power that they often have to work at. If you need more holding power then your only options are to get a bigger, or better anchor or deploy longer scope 10:1 gets you over 85%. A heavy chain does very little to help.

 

[Portofino]

A heavy chain does very little to help.

Not convinced
Look @ the maths
w divides into F --so for a given Lengh -- you want a heavier chain - turned around means more force is needed for a given Lengh with a heavier chain , shown as X ----I think ?
So 50 knot wind needed to displace the anchor with heavier chain as opposed to 30 knots for lighter chain .

Where,s JFM when you need him ?
http://abc-moorings.weebly.com/catenary-calculator.html

 

[MapisM]

Not convinced

+1. If that would be true, all ships would be carrying around hundreds of tons of pig iron for nothing.

 

[geem]

Nah disagree with that. I have snorkeled out to inspect my anchor many times in the Med and I am always surprised by how much of the chain is still on the seabed and how little it moves even in windy conditions and the boat shearing about above. If all of the chain is lifted off the seabed then you are probably in trouble because no anchor, however good it is, is going to develop its max holding power for the given seabed conditions if there is a vertical component of the load pulling it upwards

Of course it does matter how much chain you put out. In 15kt of wind I will try to put out at least 5 x depth of chain or more if possible, particularly if we are staying overnight or planning to go ashore

Btw just to drift the thread a bit has anyone got a good recommendation for a remote anchor watch ie a system which will send an alarm to your mobile whilst you are ashore if your boat moves outside a certain radius?

You must not anchor in the same conditions as us. In Caribbean anchorages winds of 30 kts gusting a lot more are common. Anchor chain doesnt touch the bottom in these conditions. Been snorkeling all over my anchor to see whats going on and chain is irrelevant. Its the anchor that does the work when the wind is up to manly status

 

[Neeves]

I did a little experiment. I took 30m of 8mm chain and deployed it at a 5:1 scope, in air. In order to get the last, or first link, off the ground took about 80kg, which is about 70kg in water. This is equivalent for a 45' yacht to about 17 knots of wind. I know you are going to say but our chain is 12mm - but your yachts weighs and have the windage considerably greater than a 45' yacht. Whatever chain is recommended for your yachts will have the same effect, chain increases with size of vessel. You may have upsized your chain - but you need to consider square of wind - and if you have a larger link maybe that 17 knots will increase to 23 knots - so what! At about 30 knots that 8mm acts like a steel rod - its got catenary but a tug on the bow roller equals a tug on the chain and then on the anchor.

But don't worry - modern anchors do work and will accept all of this, especially as you will have the facility to deploy more than 30m of chain. Even better if you stop your vessel yawing and moving up and down in waves (or at least smooth out these effects) but no-one wants to go there

An Ultra is an excellent anchor - it will bury itself like the best of them.

I could not do the same experiment with larger chain, nor longer as I did not have room (height was the restriction) and was a bit worried about pulling the fence down!

Commercial ships are usually ordered offshore when winds are forecast over 25 knots - no port facility wants a large vessel on their beach. In the extreme commercial vessel will anchor in winds over 25 knots and run their engines. Their anchoring gear, anchor, chain, windlass is simply there to allow them to wait to enter port - it is not expected to secure a ship in adverse wind.

 

[MapisM]

Their anchoring gear, anchor, chain, windlass is simply there to allow them to wait to enter port - it is not expected to secure a ship in adverse wind.

Well, that strengthens my doubt, I reckon: in spite of what you are saying, they still carry around a helluva lot of iron - also relatively speaking, I mean.

 

[Hurricane]

I'm pretty sure Hurricane said he noticed a huge difference in holding when upgrading from 10mm to 12mm chain.

Yep - I did.
Massive difference.
We always snorkle/check our anchor (when the water is clear enough).
There is ALWAYS chain on the bottom before the anchor - if not, we would let more chain out until it does lay on the bottom.

Anchor locker.
I still think S/S is better in the locker.
I suspect that out P67 chain locker is much the same as your new P68.
The problem of letting the chain build into a tower is that it can build so high that it starts to interfere with the incoming chain as it leaves the windlass.
My fear is that if it traps the flow of the chain, it could damage the windlass.

BTW
We bought our 12mm chain in Carloforte last summer.
I didn't want to throw the old out so we returned to our home berth with 70m of 10mm UNDER 150m of 12mm.
OK - so that did get a bit tight but when we got home, we removed the 10mm chain ant put it our "lockup".
The result is that if I spread the top of the chain out, I can just about sit upright in the locker on top of the chain when all the 150m is in the locker.
Even then, the galv chain does build into a tower after about 15m has been recovered.

Hope that helps.
BTW - I wouldn't go back to the 10mm and NEVER consider 8mm.
IMO That would be just plain stipid.

 

[Hurricane]

Btw just to drift the thread a bit has anyone got a good recommendation for a remote anchor watch ie a system which will send an alarm to your mobile whilst you are ashore if your boat moves outside a certain radius?

I use this one (on the Android platform)
https://play.google.com/store/apps/details?id=uk.co.slimjimsoftware.anchoralert
It does have an option to send alarms to another phone using SMS messages.

Dead easy to set up after you have anchored - point the phone and tell it how much chain you have out.

I run it on my main phone at the same time as the Navis app is monitoring wind.
I plug the phone into a USB point under my bed and put the phone in the cabin window where it gets a good GPS signal.

 

[Neeves]

Yep - I did.
Massive difference.
We always snorkle/check our anchor (when the water is clear enough).
There is ALWAYS chain on the bottom before the anchor - if not, we would let more chain out until it does lay on the bottom.

Anchor locker.
I still think S/S is better in the locker.
I suspect that out P67 chain locker is much the same as your new P68.
The problem of letting the chain build into a tower is that it can build so high that it starts to interfere with the incoming chain as it leaves the windlass.
My fear is that if it traps the flow of the chain, it could damage the windlass.

BTW
We bought our 12mm chain in Carloforte last summer.
I didn't want to throw the old out so we returned to our home berth with 70m of 10mm UNDER 150m of 12mm.
OK - so that did get a bit tight but when we got home, we removed the 10mm chain ant put it our "lockup".
The result is that if I spread the top of the chain out, I can just about sit upright in the locker on top of the chain when all the 150m is in the locker.
Even then, the galv chain does build into a tower after about 15m has been recovered.

Hope that helps.
BTW - I wouldn't go back to the 10mm and NEVER consider 8mm.
IMO That would be just plain stipid.

No-one is suggesting using 8mm (for the vessel in question), or not that I am aware. I used 8mm as an example. Small vessels use small chain 6mm, larger vessels use larger chain 13mm. You know how heavy 10mm chain is to manhandle and I can assure you 50m of 8mm is enough for me - so that is what I used in my little experiment. We use 75m x 6mm x G80 (it weighs 75kg), I wouldn't go back to 8mm (NEVER) and 10mm would be plain stupid. Its horses for courses.