Looking at your install I have a couple of questions.
1. Is that caulk inbetween the transducer and the bottom of the hull?
2. Is that a rubber gascic on the inside? If so wouldn't it be better served on the outside?
Transducer.JPG
I do not mean to come accross as critical to you installation. I have no experiance what so ever. Just wondering. I think that your install is very nice and maybe, one day, I will venture to make a simular modification.
Thanks for your post.
Paul.