You asked about where the B260 'ducer was installed on that Parker. Here
is a note from the boat's owner:

"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."

H.