I'm guessing that by "sand anchor" you mean a Danforth type.

A real Danforth, or a GOOD (read expensive) copy, is fantastic in
sand. It just digs in. I'm a diver, and I get to check the anchor every
time I dive. In a stiff breeze, my (real) Danforth will be six inches under
the sand at the end of the dive.

The cheap imitation Danforths are abysmal. One of my dive buddies had
one, and watched it drag across the sand time after time, got a good one
(one of the good West Marine knockoffs), no more problems.

But 6' of chain isn't a lot, and light might not be enough. I have a 17'
Boston Whaler, and 13' of chain (1/4" SS proof coil).

--
Chuck Tribolet

http://www.almaden.ibm.com/cs/people/triblet

Silicon Valley: STILL the best day job in the world.


"Daryl Harris" wrote in message ...
Hello all

I own a 17ft half cabin boat which weighs around 800kg. I currently have a
traditional sand anchor (sized correctly for the boat) with around 2 meters
of light chain attached to it.
I anchor the boat on in an area of beach type sand, trying to always let out
about 5 times as much rope as the water is deep. On all but calm conditions
the anchor will drag, even after diving down and digging it in by hand. I am
considering buying a plough anchor in the hope of superior holding power. I
have been told the sand anchor should be as good as any in sand and perhaps
a heavier chain would help.
Any thoughts or experiences with different anchor types would be greatly
appreciated.

Daryl