Anchors in series?

[Deleted User YDKXO]

Just had a missive from my stepdaughter who is circumcising the world in a yacht with boyfriend. She describes attaching 2 anchors to one chain in series to improve the holding power
I've never heard of this technique before. Anyone used this? Seems to me that the 2nd anchor would'nt be doing much as chain would be lifting it off seabed but maybe I'm wrong. If it works, why stop at 2 anchors? Maybe add 3rd or 4th for luck?

 

[jfm]

Seems good idea. If the closer anchor is lifting off the seabed in this arrangement then it would also be lifting off the seabed if it were the only anchor

 

[Deleted User YDKXO]

No, I dont think so. I think as the chain straightened and lifted under load it would lift the second anchor because the second anchor would'nt be heavy enough to resist it. Just my opinion. Doubtless wiser heads will soon give more learned advice

 

[hlb]

I would think that two anchors would be nearly twice as good as one. It's just getting it through the anchor winch thats the problem!! /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif

 

[trev]

Its a system known as 'piggybacking' used extensively in the North Sea for mooring oil rigs and heavy lift barges. The second anchor 'anchors' the first anchor and thus improves holding.

 

[CaptainThames]

I haven't come across this technique, but there is some logic to increasing the holding power with two anchors on the same cable. If nothing else, the weight of the second anchor (part way along the cable) would help to keep the pull on the primary anchor as low as possible, keeping it dug into the seabed. The theory though has always been that the weight of the chain itself is a significant element of the equation and this may become the weak link. I feel that I would rather put out a complete second anchor and cable (rope if no chain available) if conditions dictate. The angle between the two has to be judged on conditions and location, but say 30 degrees as a starting point. I believe this would create even greater holding power. Disadvantage is if the two get tangled together. Two anchors on one cable may be a better compromise in a restricted anchorage. Proof perhaps that what works should be used and just because it's not in the book, it doesn't make it wrong.

 

[tcm]

I reckon the first (farthest) anchor is held flat on the seabed by the extra weight of the nearer one.

So obviously, as with others, the procedures etc. adopted by this round the world sailor are very wrong and rubbish, much like er well, quite a lot of others whose exploits are related on these forums, ahem. Mind you, at least Deleted User being related to her hasn't even clouded his judgement. My only worry is that having manamged to communicate er they are talking about anchors....

 

[mjf]

There is a system called I think a running moor.

You steam up and drop one hook and then pay out whilst still blatting along (sort of Newtown Creek on a Sunday drill) then once lots of scope out you drop the other anchor as the way comes off.

Then you slack the last dropped one whilst heaving the first deployed. You end up with the boat between the two with equal scope on each anchor.

This keeps your heading whilst you remain anchored.

You can then enjoy the view whilst all about swing and pirouette.

Never done this but it must be interesting when its time to leave

 

[mjf]

Just realized that this uses two seperate anchors - so not in series.

Thread drift - sorry!

 

[Deleted User YDKXO]

They're only talking about anchors cause it didnt work. The boat nearly dragged on to a harbour wall in Turkey. Serves 'em right if they're too cheapskate to pay marina charges. Boyfriend is Scottish which probably accounts for it

 

[tcm]

um, dunno whatit's called tho i use it albeit less dramatically - just anchor with main bow anchor and pull back faceing the genral wave direction and let out loads and loads of anchor, then drop the stern anchor , and let strn anchor out as pull fwd again. Then niceley anchored towards the waves, and never mind the wind.

 

[mjf]

Standing Moor?

I used to do this too, but never ssince i got back to the Uk.

The bow& stern job works well.


The other thing I used to do was once anchored with the bow anchor lead it to a stern cleat and sit the wrong way round. Much, much less swinging about

 

[jfm]

bows onto swell

Hmm imho it works better if you swing the boat's ass right upwind then drop the stern anchor and pay out the rode as the boat swings back downwind. When you're finished, the rode of stern anchor is perpendicular to the fore-aft line of the boat and the bow anchor chain. This way you can fine tune the boat's angle and get it *precisely* bows on to the swell, using t'stern winches to adjust the amount of rode paid out

 

[tcm]

errata magnae: \"stern winches\"

hm surely some of the crew could sort out the stern winches, no? But what if the chief engineer and some of his cronies had flipped the relay off and had gone ashore in one of the dingies to buy another hamperful of footman's wigs, hm? then what?

 

[Lakesailor]

Re: errata magnae: \"stern winches\"

[ QUOTE ]
footman's wigs, hm? then what?

[/ QUOTE ]

Then Pauline is in a quandry as she loves shoes (and by extrapolation - footmen) but doesn't like wigs.

 

[paulineb]

Re: errata magnae: \"stern winches\"

ahhh but remember Phil, I have discovered online heaven. Cuts out the footmen, bald or otherwise.

 

[silvertop]

" ( circumcising the world in a yacht with boyfriend. )" had that done as a babe but with a surgens knife, A yacht seems a bit drastic, is it the bow or the keel that you sharpened.

 

[kingfisher]

Yes it exists, and it has it advantages and disadvantages.
The advantages were already discussed: it gives tremendous holding power.
Disadvantages:
1) Raising and dropping the anchors is a backbreaking nightmare, as there's a lot of weight to shift.
2) this system will NOT swing, as both anchors tend to foul each other when the tide turns. So the system is nearly useless in our waters.

 

[kingfisher]

[ QUOTE ]
um, dunno whatit's called tho i use it albeit less dramatically - just anchor with main bow anchor and pull back faceing the genral wave direction and let out loads and loads of anchor, then drop the stern anchor , and let strn anchor out as pull fwd again. Then niceley anchored towards the waves, and never mind the wind.

[/ QUOTE ]

Yes, but if the wave angle changes, your stuffed. A better option is to drop the anchor, let out the full scope minus one boat length. Attach a mooring line to the anchor rode via a rolling hitch, and let out the rest of the scope. Attach the mooring line to one of the side cleats. This way you have a spring line on your anchor line, and you can change the angle of the bow to +- 60° in reference to the anchor rode.

You anchor in the bay and are enjoying your G+T. The wave angle changes and the boat starts to wallow (allthough I doubt DianaII wallows much?). Simply attach a mooring line to the anchor line, let out more scope untill the mooring line takes some pull and then you can adjust the angle of the bow to the waves.

 

[jfm]

Kingfisher I have been planning on doing this. Glad to hear it works. I have been wondering what knot to use, and was wondering whether to get one of those chain attach devices that are used for anchor snubbers. But I'll try your rolling hitch suggestion. When I've worked out how to tie a rolling hitch......

All boats incl D2 and even much bigger stuff roll pretty badly when sideways on to a swell in an anchorage