Rocna anchor slot

[bobs]

Could anyone please tell me why the rocna slot has an oval shape ?
It doesn't work as a sarca shank slot (manson supreme anchor) because it's too small for that.
So infact , what is the reason of that particular shape ?

Thanks for any respons.
Kind regards

[Alecadi]

It´s because of the Weather change and it´s intended to keep your guns safe...

[El Pinguino]

It's so you can feed the body of a 'D' shackle through the slot so as the load comes on the 'D' of the shackle and not the pin. Hope that makes sense.......

[Sharki127]

Most anchors require two shackles, one for the anchor, one for the chain. The Rocna allows you to use just one shackle. Very clever.

[MARC D]

Ahhhhh! Learned something today! Thanks Sharki

[bobs]

El Pinguino , your explanation does make sense , but Rocna could of made that hole somewhat smaller for that purpose dont you think ?
Anyway , they did what they did.
Sharki , thanks for confirming El Pinguino's theory.

Leaves me to also thank Alecadi for shearing his profoundly insights.
I do realize my question sounds a bit silly , but if you would know the real reason for me posing it I guess (I'm quite sure) you would be the one feeling silly.

Kind regards

[skipmac]

Originally Posted by El Pinguino

It's so you can feed the body of a 'D' shackle through the slot so as the load comes on the 'D' of the shackle and not the pin. Hope that makes sense.......

But wouldn't there be a load on both ends of the shackle whether the pin or the curved end? The only difference would be whether the pin would support the load on the anchor or the chain. Either way, the pin will be supporting the same total force.

[El Pinguino]

Originally Posted by skipmac

But wouldn't there be a load on both ends of the shackle whether the pin or the curved end? The only difference would be whether the pin would support the load on the anchor or the chain. Either way, the pin will be supporting the same total force.

Yes, but with the pin going through the chain there would always be a load at right angles to the pin even if there is a windshift and the anchor han't reset. If the pin is through the shank this sort of thing can happen when the load comes from the side , scroll down to post #9 http://www.cruisersforum.com/forums/...vel-50224.html
I couldn't find a photo of a sprung D shackle but this Kong swivel has been subjected to the sort of load that has been bending Rocna shanks.

[pbiJim]

Originally Posted by El Pinguino

scroll down to post #9 http://www.cruisersforum.com/forums/...vel-50224.html

According to my rigging handbooks, D shackles aren't rated for any side load, be it in the bowl area or the pin area. The same is true of anchor shackles. The only advantage that I see from having the pin in the chain is that the consistent body diameter of the shackle in the bowl area is more likely to slide sideways in the anchor slot when the direction of loading shifts, thus keeping the pull on the shackle in the correct, load-rated direction.

I would expect that avoiding an unrated side load should help to avoid the type of failure shown in the link above. I believe that device was also not rated for side loads. I had always believed that if you were going to put a swivel at an anchor shank, you should use at least 2 chain links between the shank & the swivel to eliminate the side load probability.

[conachair]

Originally Posted by pbiJim

The only advantage that I see from having the pin in the chain is that the consistent body diameter of the shackle in the bowl area is more likely to slide sideways in the anchor slot when the direction of loading shifts, thus keeping the pull on the shackle in the correct, load-rated direction.

That's how mine behaves anyway. The shackle rotates, not possible if the pin is through a hole in the anchor.

[Neale Denman]

Yes good info as just rigging up new Rocna 10.

[bobs]

Really not to show off guys , but this is how I made mine.
Maybe it can be of some help for others
DIY Rocna anchor | Jeanneau Owners Network Forum

Regards

[sy_gilana]

most good anchors have an oval hole for the ear of the shackle to go through, and the pin goes through the chain...