Upgrade chain size or use anchor angel?

CaptainBob

CaptainBob

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Sat here at anchor with some fresher winds soon forecast. Mind wishing for better tackle.

We have 8mm chain but vessel well within size for 10mm but that needs new winch gypsy thing and chain expense. But I have about 15kg of diving belt weights I found aboard.

Wondering if using lead as anchor angel might be more effective than chain upgrade. And definitely more cost efficient.

Stats

Anchored with 40m 8mm chain out in 11m water in a 13ton ketch on a 20kg Lexmar delta.

Max wind gust fcast 23 kt.
 
Chain weight has little effect over force 6, at which catenary effects disappear and the chain is effectively straight. Adding some weight in the form of an angel will have no effect in stronger winds. 8 mm sounds slightly marginal for the size of your boat but if in good condition it should be strong enough.

Your best option is to add rope warp, increasing the scope and giving an effective snubbing action.
 
I agree with Vyv, the extra weight of 10mm over 8mm will have little effect.

The safe working load on 8mm chain is at least twice the rode tension you'll get on a 50' boat in 30k of wind, and the working load is a quarter of the ultimate breaking strength, so I think the chain is the least of your worries.
The weak link is the anchor's hold on the bottom so the right anchor, set well, is the important bit.

You'll need a little more scope, perhaps, and I'd use a long snubber to reduce snatching.

I prefer two anchors down in strong winds, set about 45 degrees apart.
 
puddock said:
Personally I'd be looking for more scope at a minimum, though 10mm chain would be my choice. What happens when the wind decides to pick up to 35+ knots :-/
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You have to take a view on whether real wind is likely before anchoring.
but it's not generally the wind which puts the peak loads on the anchor, more the waves.
Even a 1ft swell lifting the bows of an 11ton boat is going to be a big load on a line that is already taut.
I've had good results with an anchor weight, albeit with a mostly rope rode.
It can certainly improve the way the boat lies to anchor in some conditions.
My experience was that keeping the angel off the bottom at all times is best, so have it nearer the boat than the anchor. It jerks if it's on and off the seabed.

You can either do a lot of calculations, or give it a go.
 
Although Salty John's suggestion of two anchors is a possibility it will only give a marginal increase in safety since most of the load will always be taken by only one anchor. Also setting and retrieving two anchors is always a bit of pain in the ar**. Also an angel arrangement is also a bit of hassle. However both options are possible if you will only encounter bad conditions once or twice a year.

It all depends on how often you plan to be anchored out and in what conditions, will you run for shelter (marina) if over 25knts forecast??

If you plan on being anchored very often and in possibly bad conditions then you should make sure that you have a properly sized anchor, preferably one of the modern designs, and enough chain and warp for the depths and conditions you envisage. You should have confidence that your main anchor, chain and warp will hold you in 35 - 40 knts winds and waves that may go with that wind.

We are a 42ft cat, about 15 tonnes, and we anchor practically all the time. We have a 35kg Bugel / Rocna / Manson copy (self made), 70m of 10mm chain and 50m of 18mm anchorplait. This gives us the confidence to sleep soundly at night in almost all conditions and we have survived some pretty hairy places when wind has changed direction to bring big waves into anchorages!!! We have the advantage of being in the warmer Med waters so I will always snorkel over the anchor to ensure it is properly set - not so easy in UK waters.
 
crisjones said:
Although Salty John's suggestion of two anchors is a possibility it will only give a marginal increase in safety since most of the load will always be taken by only one anchor. Also setting and retrieving two anchors is always a bit of pain in the ar**. Also an angel arrangement is also a bit of hassle. However both options are possible if you will only encounter bad conditions once or twice a year.
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I agree, two anchors can be a PITA to lay and retrieve except if laid in tandem. Before the Manson, we used to shackle the Fortress to the tripping eye of the CQR lookalike and that combination never dragged.

Worst anchor loads we've experienced are with wind over tide in rivers or estuaries, when the boat sheers around in the gusts and then gets pulled up sharply. I always use a chain hook and length of stretchy nylon as a snubber, even in no wind situations.
 
I never found setting two anchors to be a PITA; we once anchored for 300 consecutive days in the Caribbean, never in the same anchorage for more than a few days at a time, mainly to two anchors either as a Bahamian moor or at 45 degrees.

The security of having two separate anchor systems down shouldn't be underestimated especially in exposed anchorages and strong winds. The Bahamian moor is essential in crowded anchorages with strong reversing currents - such as you get in, err, the Bahamas.

I've tried tandem anchoring and it just doesn't work for me.
 
Apologies for slight thread drift

Would using an anchor angel reduce my boats tendency to swing around whilst at anchor, which can be quite embarrassing when everyone else is lying quietly?
 
Ta for replies. We intend to anchor pretty much all the time, living aboard.

Funnily enough I just had to inform hm of vessel next to me dragging.

Am surprised you thing chain would go straight regardless of chain weight or angel. Surely the straighter it gets the more force an angel would be applying, becoming infinite if chain was perfectly straight?

Anyway I dropped a 15kg ish angel down to 6m and with 40m out still our chain falls much more vertically off the bow than any other vessel here. We're a little further from the fixed objects now also.

Wind fcast to drop off now and we've not dragged thus far.

Oh, another one has dragged just now also. Blimey
. Only 16kt gusts.

We used to have rocna on previous boat and sat to it alone in 40kts for a cpl of days. Wish we could fit one in our roller, but can't.
 
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lumphammer said:
Would using an anchor angel reduce my boats tendency to swing around whilst at anchor, which can be quite embarrassing when everyone else is lying quietly?
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Yes it does help for this (and not much for anchor holding in stronger winds as others have said).
An angel however create the problem that you can be too fixed in one location. The angel will make you boat behave, in light winds, as if it was anchored on a very short scope. You therefore run the risk of colliding with other boats.

The secret to anchoring in closely to other boats is to try and make all the boats move in the same way. This is best achieved by having similarly sized rodes (in proportion to the boat size) so all boats move together. Fixing the position of the boat can be counterproductive.
 
lumphammer said:
Would using an anchor angel reduce my boats tendency to swing around whilst at anchor, which can be quite embarrassing when everyone else is lying quietly?
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Yes.
If you have a light boat with a mostly rope rode, it is definitely worth experimenting.
If you keep the angel off the bottom, the boat will still pivot around the anchor, not the angel, so will move more like a heavier boat with a lot of chain out.
The bulk of the angel in the water also provides some damping I think.

In my limited experience, it improves holding on poor ground with an anchor that is perhaps on the small side. I'm not really into anchoring through gales, but I am confident that in the particular case of my boat with a CQR, an angel can improve holding.
 
Well we didnt drag at all with our setup as stated in op plus 15kg "angel" at abou 6m under water. Seems like almost every other boat did! At least one had to get a diver out to recover their Manson supreme which got caught up in a ship buoy outrigger chain.

As per my last post, am surprised the panel think that heavier chain or an angel won't make any odds in stronger winds, suggesting the rode would be dead straight anyway. I looked up the anchor buddy website comments on th subject and they disagree. Tis a bit sales pitch stylee mind you. But as I said before, to make it dead straight would need an infinite amount of load, or an zero weight chain, surely? So heavy chain or an angel therefore must both result in a lowering of the angle of pull on the anchor?

Anchor buddy site is here...

http://www.anchorbuddy.co.nz
 
CaptainBob said:
As per my last post, am surprised the panel think that heavier chain or an angel won't make any odds in stronger winds, suggesting the rode would be dead straight anyway. I looked up the anchor buddy website comments on th subject and they disagree. Tis a bit sales pitch stylee mind you. But as I said before, to make it dead straight would need an infinite amount of load, or an zero weight chain, surely? So heavy chain or an angel therefore must both result in a lowering of the angle of pull on the anchor?
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It's not stronger winds, but *really* strong winds. The chain won't be dead straight but takes less force than you might think to lift the whole lot off the sea bed even with an angel.

http://alain.fraysse.free.fr/sail/rode/dynam/dynam.htm
http://alain.fraysse.free.fr/sail/rode/synthesis/synt.htm


Though a nice heavy chain does stop you sailing round the anchorage quite so much.
 
I have dived to view my anchor and chain many times in strong winds in the Med. I can assure you that when the wind reaches about force 6 the chain is completely off the bottom for a fair proportion of the time and pretty much straight. On one such occasion, in Sardinia, we were anchored in only about 2.5 metres of water with 35 metres of 8 mm chain out. Craig Smith posted photos of his father's yacht at anchor in the Magellan Strait in strong winds, 100 metres of chain out, apparently perfectly straight.

You can read some of the mathematical theory behind it on Alain Fraysse' website at http://alain.fraysse.free.fr/sail/rode/rode.htm He does not specifically mention angels but he discusses chain weight in some detail. The late Alain Poireaud posted many times about angels and the fact that they have little effect in stronger winds. As the designer of the Spade anchor, he knew a thing or two about anchoring and was pretty hot on the maths.
 
Interesting website. Thanks for posting. A bit concerning.

Shame he hasn't also done the maths with an angel in the system.

The anchor buddy website suggests it acts as a very effective load reducer because it slows the boat down in the dynamic situations.

From the website you cite though:

1. The critical force Fc is proportional to w. Consequently, for a given length L, using e.g. a 10 mm (3/8") instead of 8 mm (5/16") chain increases Fc by 44%. The main drawback is a 44% increase of the weight carried on board.

Which suggests that 10mm chain is 44% better than 8mm chain, for the same situation, which is quite an improvement.

Also might suggest therefore that an "angel" in the system could actually be quite effective, without having to upgrade the chain and carry quite as much additional weight.
 
I must admit my thought would have been to invest in a longer length of chain, in my opinion 40m in 11m is perhaps marginal if the wind pipes up even with 10mm.
 
vyv_cox said:
I have dived to view my anchor and chain many times in strong winds in the Med. I can assure you that when the wind reaches about force 6 the chain is completely off the bottom for a fair proportion of the time and pretty much straight. On one such occasion, in Sardinia, we were anchored in only about 2.5 metres of water with 35 metres of 8 mm chain out. Craig Smith posted photos of his father's yacht at anchor in the Magellan Strait in strong winds, 100 metres of chain out, apparently perfectly straight.

You can read some of the mathematical theory behind it on Alain Fraysse' website at http://alain.fraysse.free.fr/sail/rode/rode.htm He does not specifically mention angels but he discusses chain weight in some detail. The late Alain Poireaud posted many times about angels and the fact that they have little effect in stronger winds. As the designer of the Spade anchor, he knew a thing or two about anchoring and was pretty hot on the maths.
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He does mention Angels, calling them 'kellets'.
He only refers to them being used to reduce the angle of elevation of the chain at the anchor, which is I think missing the point.
One thing which does come out of his spreadsheets is the lower peak force on the anchor with a nylon rode in dynamic conditions.
 
maxi77 said:
I must admit my thought would have been to invest in a longer length of chain, in my opinion 40m in 11m is perhaps marginal if the wind pipes up even with 10mm.
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Didn't have a choice, we had obstructions. I'd have had more out if I could. But the wind was gusting well over 20 knots, at least 4 other boats dragged on various anchor types, and they were in less water, and we did not move a mm. Maybe it was the angel that kept us in place. We have a lot of windage too being a big and heavy set ketch (Nauticat 38)
 
CaptainBob said:
Didn't have a choice, we had obstructions. I'd have had more out if I could. But the wind was gusting well over 20 knots, at least 4 other boats dragged on various anchor types, and they were in less water, and we did not move a mm. Maybe it was the angel that kept us in place. We have a lot of windage too being a big and heavy set ketch (Nauticat 38)
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That seems so often the reality.
It's pretty rare I've wanted to anchor somewhere in a breeze and had space for an 11:1 scope.
 
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