On Wed, 14 Jun 2006 23:38:53 -0400, Ed wrote:

I have a $2000 unit and a $1200 unit on my sportfish with expensive
transducers, etc. They work OK at 20Kts but not over 200ft deep unless
I am going about 8Kts then it will read to 600ft..

I have a 600 watt Furuno Navnet sounder connected to an inexpensive
thru-hull transducer. We get reliable depth readings up to about 1600
feet at trawler speeds of 8 to 10 knots.