On 23 Feb 2007 07:57:09 -0800, "mark" wrote:

I am going to buy a sounder for use in my aquaculture operation. I
need it to be as accurate as possible in determining if my mussel
socks are touching the bottom or are 1' off the bottom. The water is
only 20 feet deep and it is a mud bottom. Some people are using SiTex
106-L which has 300 watts of power and 50 or 200KHz and some are using
Furuno FCV 620 which has 600 watts of power and I saw one with a
Hondex. For my application is there any advantage of one over the
other? Also My boat is aluminum and some dealers are telling me to use
a bronze transducer but make sure it is isolated with plastic bushing
and other are saying use a special ordered aluminum transducer. And
finally would it be most accurate if it pointed straight down or would
having it 10 degrees off to one side (flat against the hull) make a
big difference, if so could I fabricate a level flat spot on the hull
to mount it to but would this create to much turbulence for it to read
properly? I want it as far forward as possible not on the stern. Thanks

In 20 ft of water, you can use a sounder with the least power
available. It would be better to avoid dissimilar metals for obvious
reasons. I would feel reasonably comfortable with a transducer at a
ten degree cant - because for this depth, you can easily verify the
reading with a string and a lead weight one time

Brian Whatcott Altus OK