Rocna anchor for GS52

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Herminia
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Rocna anchor for GS52

Postby Herminia » Fri May 23, 2014 4:24 pm

Hi all,

I am looking into buying a new anchor. I have excellent experience with the Rocna 25 on my previous vessel and would like to go for the same brand now. Looking at the Rocna website, I have found the Rocna 40 to be the correct size for the GS52. But as I am not in the boat now, I wonder if anyone know if either a Rocna 40 or a Rocna 55 will fit on the original bow arrangment?

8-)
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Rune
Grand Soleil 52 "Herminia"
Cruising Spain

streetcar
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Location: Fiji

Re: Rocna anchor for GS52

Postby streetcar » Tue Jun 03, 2014 10:12 am

Hi Rune

We have a Rocna 40 on our GS 52 and it fits OK... but not perfect. I think our bow roller is standard, although I am not certain. It has 2 bronze rollers mounted in stainless steel jaws.

Anyway I rate the Rocna very highly. However we have dragged it once. This was in very soft mud in Suva harbour and it ploughed slowly along without ever breaking out. This was in 30 to 35 kts wind and 1m seas. I was a little surprised and now consider switching to our spare Bruce when I am in soft mud.

Back to the fitting. The shaft on the Rocna 40 extends right back almost to the chain locker cover, but it does not prevent it closing. The problem is that the point of the anchor is very close to the stem of the boat. When the anchor is being launched and recovered the point sometimes hits the gelcoat causing scratches and worse. One other problem is that the Furlex drum on the genoa furler is very low and is sometimes hit by the anchor shaft during recovery. You may of course not have the same system.

I have planned to redesign the bow roller to accommodate this anchor properly, but cost is excessive. So I deal with the problems manually. When launching the anchor I let it out by hand until it is hanging safely. It is surprisingly easy to do this. When recovering the anchor, I bring the last bit up very slowly and carefully on the windlass (using boat hook to hold the 'bow' on the end of the Rocna) and by ignoring Health and Safety I can use my foot to steer the shaft under the furler.

Finally you should also consider how the Rocna will be secured when sailing into big seas. If it is just on a bow roller, the Rocna can move up and down as waves hit it. This is because it has a vertical straight section between the 'shaft' and the 'spade'. Rocna recommend having struts from the roller assembly down to the 'spade' to prevent it jumping up. I have spent many hours smashing into seas trying to relash the anchor to prevent it 'jumping' and still haven't found a good way of lashing it. Even spectra breaks under these repeated loads.

In the end if you want a good system for the Rocna on the GS 52. Then I would consider redesigning the bow roller assembly.

Let me know if you want pics.

Cheers
Rory

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Herminia
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Re: Rocna anchor for GS52

Postby Herminia » Wed Jun 04, 2014 2:54 pm

Hi Rory,

Thanks for the detailed report, much appreciated. I have attached a picture of my bow arrangement. I don’t think I will have the same problem with the head sail rollers as they are hydraulic. Do you have the same stainless steel protection as I have? Maybe mine will protect the hull against the tip of the anchor? If these two problems are solved, then the only issue would be to secure it. There is a purpose made hole in the Rocna and also in the roller. But they are not aligned so I would need to investigate how I best can secure it. The best would be to extend the roller assembly to align with the holes in the Rocna anchor and insert a pin. Or drill a new hole in the Rocna to align with the bow assembly.

Anchor arrangment.JPG
Anchor arrangment.JPG (25.15 KiB) Viewed 2716 times
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Rune
Grand Soleil 52 "Herminia"
Cruising Spain

streetcar
Posts: 70
Joined: Wed Jan 08, 2014 7:58 pm
Location: Fiji

Re: Rocna anchor for GS52

Postby streetcar » Wed Jun 04, 2014 9:10 pm

Yes, I agree, it looks like your only problem will be to secure the anchor. Your bow roller arrangement looks identical to ours.

On using the pin:
I definitely would not drill a hole in the new Rocna.
I once sailed on a boat where we secured the anchor with a pin before sailing into some big seas. When we arrived and tried to release the anchor we found the pin had bent and could not be removed. We had to cut it. The impact forces are very surprising.
I only use the pin to prevent a mooring line jumping off the roller.

Other options:
Rocna provide good advice on bow roller assemblies. See http://kb.rocna.com/kb/Bow_roller_assembly_design
They recommend cheek plates as a way of holding the anchor down. This sounds the best solution to me, but I need to be somewhere that can do this job.
My next plan is to devise a teak block to insert between the stem and the anchor tip to hold 'wedge' the anchor. Not sure how this will work.
Also we will endeavour to only sail with the wind and waves.

The only other thing I was going to say is that the 'default' bronze bow rollers on the GS52 are curved in profile and do not secure the anchor shaft from lateral movement (sliding sideways across the roller). I got a small recess machined into the roller for the shaft to sit in.

By the way we are currently tied up in a marina opposite a 30 year old GS46. It is in beautiful condition and has been immaculately looked after. I will take some photos later and post them.

Cheers
Rory

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Herminia
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Re: Rocna anchor for GS52

Postby Herminia » Fri Jun 06, 2014 8:30 pm

Thanks for the link to the Rocna recommendations. They very much confirm what you mentioned regarding a pin and that it's a bad idea to make a new hole in the anchor. Based on that, I will use either rope or a wire to start with and investigate further this summer.

The GS46 is a very beautiful design indeed, looking forward to the pictures!
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Rune
Grand Soleil 52 "Herminia"
Cruising Spain


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