On Thu, 01 Nov 2007 09:50:54 -0700, Bob wrote:

If anchoring in sand bottoms (hard, loose, sand/mud) why would I chose
the Rocna instead of an anchor design specifically for such
conditions; Fortress FX series. In other words, Fortress FX or Rocna?
Which holds best in sand or mud bottoms?

Or is the Rocnca's appeal that it holds adequately in a variety of
bottoms? Say, the better crescent wrench (adjustable spanner for you
Limeys).

There's a couple of reasons and they apply equally to the Spade and a
few others of this type. Danforth type anchors, including the
Fortress, have great holding power if they are well set in favorable
conditions, typically firm mud or sand. They also have a few notable
weaknesses however: Unfavorable bottoms like grassy or rocky; and even
more important, the ability to get down through the water and set in a
boat that is moving, or in strongly moving current. Danforth type
anchors will plane like a water skiier if you need to deploy them from
a moving boat. I've seen it happen and it convinced me to buy a CQR
at the time, many years ago. Danforth types also have an unfortunate
habit of fouling a fluke on their own rode with a directional shift,
or somtimes on a shell or rock which prevents the flukes from pivoting
to the proper angle.

As a result I've come to view Spades, Rocnas, etc. as better all
around anchors but I still carry a Danforth for special circumstances
where I need something lighter light weight.