On Fri, 18 Jan 2008 09:30:14 -0500, HK wrote:

"I had it installed when I got the boat. It has the high speed fairing
block and is mounted about 18 inches in front of the transom and about a
foot off center on the starboard side. Those are just guesses. I can
check and measure if it will help you. I think there is a better ducer
out now. Not sure what number it is, but I hear it's about the same as
far as quality but it has a larger cone angle on the hi freq 200 that
matches the cone angle of the low freq 50."

Why bother with all that. I have the Airmar dual frequency transducer
shooting through the hull of the Grand Banks. The hull is about an
inch of solid fiberglass and it works fine up to about 1700 feet of
water.