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post #7 of Old 05-01-2009
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Wrote this for another forum:

To give you an idea of what the forces are like, this table is based on one found in The Complete Anchoring Handbook, by Alain Poiraud, et al.

Of course, it depends on the windage of your boat. A bimini, dodger, roller furling headsail, etc., will all increase the forces on the anchor.

The numbers above assume that the boat is solidly anchored... and those numbers will change, depending on what kind of bottom the anchorage has, what kind of anchor you're using, and things like that.

To give you an idea of what forces an next generation anchor like the Rocna can generate, the 15 kg version was found to repeatedly hold in excess of 4500 lbs. of force. The 10 kg Rocna will obviously not generate forces quite that high, as it has a much smaller surface, 795 sq. cm. vs. 1030 sq. cm. Assuming the surface area is proportional to the force it can generate, the Rocna 10 would be able to generate 3500 lbs. or so repeatably.

Based on that, the rope portion of the rode would be the weak link, provided you're using a load-rated shackle for the anchor-chain connection. This is why I was recommending upsizing to at least 9/16" line.

Originally Posted by FishFinder View Post
Good stuff thanks guys that helps a lot. What about info on anchor line/chain loads and rigging loads?


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Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

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