Plastimo Kobra Anchors

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anniebray

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My new boat came equipped with the above anchor (10Kg Kobra 1 ) which has a patented folding mechanism for easier stowage. Have to admit that I didnt study before use & found that it didnt grip. When I hoisted it up I noticed that it had folded. I tried a few times without success. Has anyone else used this anchor & did it work properly for them ? If so please describe how you set it ! I'm wondering if I should permanently lock it in the open position for satisfactory results.
 
Don't know this anchor but 10kg is quite light for the boat and light anchors are always more likley to skip accross the seabed if its a bit difficult. You might be better using this one as a kedge and getting something around 15kg for a bower
 
We use a 14Kg Kobra, and have used it for 3 or 4 years now.

It sets brilliantly. Always unfolds as it should.

Have you actually seen the anchor not unfolding correctly underwater? My guess is that any problem you have is due to the low weight.

If you send me a pic, I'll look to see if there appears to be a fault.

TonyMS
 
I would agree that 10kg is not enough for my boat's main anchor (probably 5.5 ton all up cruising) although a 10Kg Rocna gets pretty near & might suffice. My partner & I don't have much experience anchoring but we dont plan to do so in heavy weather (I know could get caught out !)
There appears to be some kind of instruction on a transfer on the shank & it would seem that one should twiddle with the locking cam devices before launching but I cant find written instructions anywhere. Next WE will try again !
 
If this is a new boat and the builder supplied it, then surely your first point of call is Sadler. Ask them to explain why they supplied this product and how it should be used. Thats what you pay umpteen 10's of thousands of your hard earned cash for. If you bought the boat second hand ask the previous owner.
 
FWIW from a broker's site :

" The Kobra anchor, folding (patented).
The Kobra anchor bites into the seabed within seconds and has a very high holding power, thanks to its weighted tip and very broad shoulders.
Constructed from high resistance galvanised steel.
Cleverly designed to be stored on the bow roller or stowed in the chain locker thanks to its collapsible shank.
The outstanding performance of the Kobra results from its particular geometric proportions, which allow you to select safely up to 2 sizes down compared to the usually recommended anchor weight.
Its high holding power makes it ideally suitable for use as a picnic anchor, used in conjunction with a weighted mooring line. This reduces the efforts necessary in the absence of a windlass."
 
The configuration looks very like the Delta which is one of the most effective types available. I would ensure that the anchor is locked before deploying.
 
Is the 'twidly bit' a means of adjusting the angle between the shaft and the blade? If so it should be a shallower anngle for sand/hard seabed and a steeper one for soft/mud
 
[ QUOTE ]
My new boat came equipped with the above anchor (10Kg Kobra 1 ) which has a patented folding mechanism for easier stowage. Have to admit that I didnt study before use & found that it didnt grip. When I hoisted it up I noticed that it had folded. I tried a few times without success. Has anyone else used this anchor & did it work properly for them ? If so please describe how you set it ! I'm wondering if I should permanently lock it in the open position for satisfactory results.

[/ QUOTE ]Assymmetrical anchors of the three-point geometry style will drag with the shank folded down if there is nothing to keep it help up. Until buried deep in consistent substrate, the forces on the shank are such that the shank would collapse downward (not be pulled up into position).

If this is the case, the fluke will sit flat on the seabed and never start to dig in - just skate across the top. If this is the case, it should be obvious, as when trying to set the anchor you will get next to no resistance at all.

As above the Kobra is essentially a Delta variant/copy, and performs okay in tests, so should give reasonable performance. Check the folding mechanism. For the above reasons, it is a load bearing part.

If you can't satisfy yourself as to its reliability, look at upgrading to a new generation type of the same size, which will give greater reliability and higher holding power.
 
Not at all; the Kobra 1 has only 2 states: folded, or unfolded with a more or less reliable mechanism (2 cams) to keep it so. That is why Plastimo sells a Kobra 2 with a fixed shank (bolted in place): I use it successfully as main bower. And I usually block the cams with a small bit of halyard before using my Kobra 1 kedge.
 
Now that seems a fine idea ! I had been thinking of attaching a small length of trailing rope to the anchor to assist when setting & recovering. Its quite difficult to manoeuvre the anchor to avoid damage to the hull and genoa furling drum. One could pass the rope outside the pulpit to provide extra lift & this rope could at the same time positively secure the folding mechanism.
 
Once you get it sorted I would give the 10kg a fair test, you may find out it does the job. I use a 10kg Bruce (with 45m chain) on a similar boat and have had no problems and I do anchor a fair amount. I actually have a 15kg Bruce at home and it would fit the locker (just) but lugging it about would be no joke, esp with chain and nylon out in deep water.
 
10kg with a good leader of chain should be enough for a 5-tonner - if it sets properly. I suspect that it is not setting. Try anchoring in clear, shallow water (if you have such conditions available locally!) so you can watch what it does on the seabed.
 
I've used both a real Delta and the Kobra and I feel the Kobra is the better holder. They both seem to set, but the Delta seems to drag even though it is still embeded. A Spade is also similar in design to both the Kobra and Delta. I am not sure which design came first. According to Several tests I seen over the years and many locations Spade is the best of the three, Kobra is 2nd, and Delta a distant third. One thought is you might want to check the geometry of your bow roller and deck layout first for fit up with the anchor. There is a considerble difference between the shank length and geometry. I wanted a Spade on my Cal 31, but the Kobra fit my anchor roller and anchor well hatch better than the Kobra.

Greg
S/V "Evania"
 
roly_voya said:
Don't know this anchor but 10kg is quite light for the boat and light anchors are always more likley to skip accross the seabed if its a bit difficult. You might be better using this one as a kedge and getting something around 15kg for a bower
Click to expand...

It has always been my thought that an anchor has no idea how big the boat is. Thus it is only when the anchor is reaching its limits that it will fail, and this could be due to a steady pull, a snatch, or a change in the angle of the rode.

If the anchor isn't holding in any conditions where there is a bit of tension in the rode, it's more likely not setting for a reason to do with the anchor, rather than the boat it is attached to.
 
thudbranch said:
I've used both a real Delta and the Kobra and I feel the Kobra is the better holder. They both seem to set, but the Delta seems to drag even though it is still embeded. A Spade is also similar in design to both the Kobra and Delta. I am not sure which design came first. According to Several tests I seen over the years and many locations Spade is the best of the three, Kobra is 2nd, and Delta a distant third. One thought is you might want to check the geometry of your bow roller and deck layout first for fit up with the anchor. There is a considerble difference between the shank length and geometry. I wanted a Spade on my Cal 31, but the Kobra fit my anchor roller and anchor well hatch better than the Kobra.

Greg
S/V "Evania"
Click to expand...

This thread dates from 2008, so I guess the OP has his answer by now. Just for your info, a Spade is very much NOT similar in design to a Delta and a Kobra. The Spade is a concave New Generation anchor, very expensively built. The Delta and Kobra is a convex plough design , which while perfectly acceptable for many anchoring situations is not in the same league as the Spade. Where the performance of ploughs falls down in particular is in soft, muddy bottoms, where they tend to drag.
 
Vyv,

I hate to suggest disagreement but in Fortress Chesapeake mud tests (and ignoring the fact the Fortress did well) both the Spade and Rocna (and both have a very similar fluke profile and might be called 'New Generation) were pretty appalling - but with the Spade having the edge. If you anchor in a lot in mud - buy a Fortress and a decent deck wash :)

And on Kobra - a very good design, I'd say excellent, but built cheaply which compromises critical elements of its performance.

We have a Kobra - and had the shank welded up but still would not use it as a primary

Jonathan
 
Neeves said:
I hate to suggest disagreement but in Fortress Chesapeake mud tests (and ignoring the fact the Fortress did well) both the Spade and Rocna (and both have a very similar fluke profile and might be called 'New Generation) were pretty appalling - but with the Spade having the edge. If you anchor in a lot in mud - buy a Fortress and a decent deck wash :)
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I didn't mention Rocna, I was comparing my own experience of anchoring in soft mud with plough and NG anchors. I don't doubt that the two NG anchors you mention did poorly in what seem to me to be unusual conditions but how did the ploughs do? (I have not read the report as YM declined to participate)
 
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