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Old 02-13-2011, 07:59 AM   #241
Brian-Fortress
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Join Date: Jan 2011
Posts: 27
Rocna owners, seems you need a better anchor

Eric's description of the benefits from using a wider shank/fluke angle in soft mud is accurate. This wider angle, which is 45° on the Fortress, will put the flukes in a position where they will provide much greater resistance in a soft mud bottom. I have attached a simple image which might be helpful in understanding this.

Unfortunately, in harder soils it will be difficult to set the anchor at the 45° angle, as it will have a challenge penetrating the sea bottom and it is likely to simply bounce along the harder bottom, so the anchor must be re-set back to the 32° angle to work properly there.

While the Fortress holds a US patent on the adjustable fluke angle anchor, it is certainly no secret among anchor design experts that a wider fluke angle offers far greater performance in soft mud.

I believe that guys like Robert Taylor of the US Navy, who wrote the anchor performance guides for the American Petroleum Institute, and companies like Vryhof in Holland have been designing anchors with this feature for decades in the offshore oil & gas industries.

If you guys really want to dig into this deeper, go to the Vryhof web site and download their "anchor manual." Then turn to page 32, which is interesting reading, and look at figure 2-10.

http://www.vryhof.com/

Regards,
Brian

Fortress Marine Anchors


-- Edited by Brian-Fortress on Sunday 13th of February 2011 10:01:27 AM
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