Letting out too much anchor chain

[PEJ]

Anchor chain question.

Lets assume a normal situation anchoring for a few hours at a bay and no change of tide direction due. A few other boats nearby but not too packed.

Lets say it is 3m deep so you should let out 12m of chain.

Lets say you err a bit too much on the cautious side and let out 20m or 25m.

Is this a problem?

 

[MapisM]

No.
Actually, I wouldn't be happy at all with a ratio of 4 in a 3m depth.

 

[jimmy_the_builder]

Well, I guess it depends on how you set the anchor, but you'll probably just swing around a big pile of chain on the seabed when the tide turns. So in a practical sense, all other things (wind etc) being equal - not a problem.

Cheers
Jimmy

 

[DAKA]

I check the fall and rise on the chart plotter each time I anchor.

eg.

Channel islands 1400 hrs 2m
you say 3 hours 1700 hrs 8m
you have 3 under you know total 9 = 36m of chain to pay out plus 2 from the anchor roller.

Solent only rise 2m in 3 hours plus your 3 = 5 x 4 plus roller to water = 22m

IMHO you are not been over cautious with 20-25m in 3 meter of water.



It all goes wrong when someone arrives just before high water and lays 30m in 3 m of water and then swings round scooping everyone up .

 

[jfm]

No.
Actually, I wouldn't be happy at all with a ratio of 4 in a 3m depth.

+1. 12m is too little in 3m of water. These 3x or 4x rules are questionnable at the best of times, but in such shallow water they lead to too small an amount of chain. 20-25m is a sensible amount of chain for 3m water depth

 

[Hurricane]

You really need to swim in clear water after anchoring to really appreciate how well an anchor has taken.
Even after five years, we have now only just started to understand anchoring.

Every time we anchor, as soon as the engines are off, one of us dives in with a mask and snorkel to check on it.
The amount of chain on the bottom is always a consideration.

I always used to give the anchor a good tug using the engines to see if is "dug in" but these days, I'm much more precise
We tend to motor up to a sandy bit, drop the anchor in the sand and then let out as much chain that suites the environment.
If there is plenty of swinging room, we will let out lots of chain
If its a tight anchorage with a danger of swinging into other boats, you can't let as much out.
But we always ensure that there is a good amount of chain on the bottom before it reaches the anchor itself.
Then, as the wind picks up, we keep an eye on the amount of chain on the bottom - either by letting some out or moving on.

Of course, this all depends on anchoring in clear warm water
During our experience in the UK/Solent we had no idea what was going on

 

[Deleted User YDKXO]

Lets say you err a bit too much on the cautious side and let out 20m or 25m.

Is this a problem?

Its only a problem insomuch as you might swing into other boats nearby if they are lying to a shorter length of chain. If it was a relatively calm day and I was staying on board all the time, I'd be happy with 5 x depth ie 15m but make sure the anchor is dug in. If I was going ashore for lunch, then I'd definitely want 20-25m out and be sure that there was plenty of swinging room. Of course you will never stop some numpty dropping his hook right next to you but if your boat swings into him, its his problem. Just put some fenders out

 

[Deleted User YDKXO]

You really need to swim in clear water after anchoring to really appreciate how well an anchor has taken.

You do know Studland Bay is in England? The water temp has only just risen above freezing

 

[KevB]

Off course if everyone put out shed loads of chain the boats would be over everyone's anchor and chain, even if the boats themselves are at a distance. Not a problem till you want to leave.....

It's sometimes obvious to spot the boat who has just dumped too much chain as they merrily swing around a pile of chain in a different direction to everyone else. Is amusing to watch the skipper keep looking at the other boats wondering why he is 90 deg out.

 

[benjenbav]

You do know Studland Bay is in England? The water temp has only just risen above freezing

Whilst I recognise this as a light-hearted remark, I would say that last weekend we actually had 18C in the Lymington river and 15C in mid-Solent. Still not warm enough for me to swim.

 

[Deleted User YDKXO]

Whilst I recognise this as a light-hearted remark, I would say that last weekend we actually had 18C in the Lymington river and 15C in mid-Solent. Still not warm enough for me to swim.

Crikey, I'd want a defibrillator on stand by before I even dipped a toe in that

 

[jfm]

It's sometimes obvious to spot the boat who has just dumped too much chain as they merrily swing around a pile of chain in a different direction to everyone else. Is amusing to watch the skipper keep looking at the other boats wondering why he is 90 deg out.

I don't get that at all. Putting out more chain makes you lie at 90 degrees to the other boats on shorter chains?

 

[PCUK]

All depends on your ground tackle. If it is too light then you will need to let out five times or more.

 

[NormanS]

When you are considering the depth, you should really add on the height above water to your bow roller, and then multliply that by whichever figure you choose. The shallower the water, the greater the multiplier should be.

 

[Elessar]

+1. 12m is too little in 3m of water. These 3x or 4x rules are questionnable at the best of times, but in such shallow water they lead to too small an amount of chain. 20-25m is a sensible amount of chain for 3m water depth

25m. Flip you need a Rocna.

25m in 4 m of water plus Match = about 85 m of swing.

Not much room like that in these parts.

 

[MapisM]

25m. Flip you need a Rocna.
25m in 4 m of water plus Match = about 85 m of swing.
Not much room like that in these parts.

Actually even more, unless among other customizations jfm asked also to shorten the 24m LOA somehow... Anyway, so what?
He doesn't need a different anchor - and I'm saying this without even knowing/remembering what anchor he specced.
He just must find adequate anchorage areas. Same as with any other vessel, really.
The Oasis of the Seas needs even more room, and in spite of that I'm pretty sure that she doesn't use a Rocna...

 

[Philiz]

Off course if everyone put out shed loads of chain the boats would be over everyone's anchor and chain, even if the boats themselves are at a distance. Not a problem till you want to leave.....

It's sometimes obvious to spot the boat who has just dumped too much chain as they merrily swing around a pile of chain in a different direction to everyone else. Is amusing to watch the skipper keep looking at the other boats wondering why he is 90 deg out.

Why? Surely each boat will be affected by wind and tide in the same way irrespective how how much chain is out. How can the amount of chain on the bottom influence which way your boat faces?

 

[henryf]

I'm also curious as to how the amount of chain you let out would dictate how your boat lay.

I would have thought having a keel would mean more of a tendency towards the current influencing your orientation, less of a keel and more in the way of top sides means wind has a greater effect.


That and localised eddies in the current particularly as the tide comes to high or low water.

The great thing about the Solent is our glorious mud, far better than your horrible sand

Henry

 

[benjenbav]

I'm also curious as to how the amount of chain you let out would dictate how your boat lay.

I would have thought having a keel would mean more of a tendency towards the current influencing your orientation, less of a keel and more in the way of top sides means wind has a greater effect.


That and localised eddies in the current particularly as the tide comes to high or low water.

The great thing about the Solent is our glorious mud, far better than your horrible sand

Henry

I'm told that all sensible hippopotami enjoy mud, glorious mud:

 

[Deleted User YDKXO]

25m. Flip you need a Rocna.

25m in 4 m of water plus Match = about 85 m of swing.

Not much room like that in these parts.

Understand the maths and Mapism's comment but my observation from snorkeling out and watching my own anchor is that the boat only swings about the the part of the chain that isn't on the seabed. With 25m of chain in 4m of water, unless its v windy, at least 15m of chain will be on the seabed so the boat is only swinging about 10m of chain and, in any case, I'm not sure that any boat swings through as much as 180deg.