Tandem Anchoring

[jimi]

In poor holding would there be any benefit in attaching say 2 metres of chain to a tandem anchor attachment point or would this just encourage the anchor to capsize and if so, would'nt a tandem anchor do similar? Would'nt one just be better off with a lot of chain between anchor an vessel?

 

[ccscott49]

I like lots of chain between anchor and boat, tandems do work, but not if you are swinging around too much.

 

[Salty John]

I agree with getting lots of chain between boat and anchor. The concept of tandem anchoring worries me because of the potential for tangling when the boat moves in reversing currents or widshifts. A well proven anchor type for the conditions and lots of chain is the way to go. In strong reversing currents I use the Bahamian moor, one anchor up current, one down current. The anchors stay far apart and don't get tangled. I like the CQR in this situation because it has a hinged shank that rolls over as the boat turns and has less tendency to unset itself. In heavy weather I use two anchors off the bow about 45 degrees apart which gives great security with minimal chance of getting the anchors tangled.
All in my own personal experience, of course, and I'm sure others will have widely differing views!

 

[jimi]

I was going to say I usually chain my bike to some railings .. but that would just have been facetious and I'm not like that

 

[Salty John]

If you chain your tandem to a railing make sure you secure it fore and aft or the thief can exert enough leverage to break a normal bike chain. Only my opinion, of course.

 

[Twister_Ken]

Daisy, Daisy give me your anchor do
I'm half crazy, oh for the muddy glue
It won't be a stylish anchorage though
Coz I've only got a Beneteau
But it'll look sweet
Hooked round the cleat
Of a windlass made for two

 

[Lakesailor]

The main drawback with tandem anchoring is that the saddles get wet.

 

[ChrisE]

In the spirit of I'm Sorry I Haven't a Clue, could you please sing that to the tune of It's a long way to Tipperary?

 

[Gunfleet]

Us Raries

Don't mind being tipped, as long as it's in cash.

 

[jhr]

Daisy, Daisy

Bravo! Alternatively, to the tune of the Floyd's Bike Song:

I've got a boat
It can hardly even float,
It's got a rudder, a holding tank
And something called an anchor
I have to sail alone 'cos I'm a [no thanks]

Anchoring's a no-no
When I do it solo
Though it's really gruesome
I have to use a twosome..................

Eat yer heart out, Syd.

 

[hylass]

back to technology..

I have a different position regarding the use of two anchors..

If you use two anchors “V” set, you will not increase the holding of each of them, but as you can easily check the holding of each of them, you have more chances that they will both be set.. and if one drag, the other one would have some chance to hold..

On the same way, if one anchor rode will break. You will still be anchored on the second one..

Now, about the “tandem set “technique..

Or the “Double Trouble” technique:

Attaching two anchors to one rode, known as tandem anchoring, should be avoided. The double approach attaches a second anchor with around 15’ of chain in front of the first anchor. I personally almost lost my boat trying out this idea. At the time, my first anchor dragged. Needless to say, it was an old generation model, so I decided to try something new. I added a smaller anchor in front of the large one. This worsened the holding power as opposed to doubling it, drifting swiftly on the smaller anchor while the larger one couldn’t grip at all.

On an imaginary level, it might seem like two anchors should hold better than one. This is however only true when both anchors can set perfectly. Whatever anchoring technique you use, there’s never a guarantee that both anchors are going to set well. On the contrary, once the first anchor is set in the seafloor, it will hinder the other anchor from setting also.

When an anchor has dragged, a trench formed behind it and this quickly backfilled with loose un-compacted sand. These areas can be still visible after several tides and may explain why some popular anchorages are criss-crossed with patches of poor holding.

Then, if the most proximal anchor set, they are very good chances (?) that the distal anchor will fall down in this loose bottom, with, as a consequence, a poor holding!.

I have done a series of approximately 70 tandem anchorages in the clear waters of the Med, diving on nearly all of them.. in 62% of the cases, only one anchor was set.. During bad weather, you will not have the possibility to dive to check your anchors.. and you only have to “trust” your anchors.. Which is what I call “the Russian Roulette” anchoring..

For those who insist on using two anchors on one rode, I offer the following suggestions:

• Only use two identical anchors, with the same size and model.
• The size of each anchor should be able to withstand the load of your boat on its own, without the second one.
• The two anchors should be separated by a piece of chain of around 3 to 5 meters in length.
• Never attach the chain from the second anchor directly to the first anchor; instead, attach it to the connector of the first anchor.
• Finally, remember that new generation anchors have holding power far superior to older models, and they do not suddenly disengage from the seafloor like plate or CQR anchors. Instead, they slowly drift, remaining embedded. I am convinced that a single new generation anchor with high holding power is safer and more reliable than linking two old generation anchors tandem set.