This .PDF should help those of you with selecting the right transducer for your application.
Things to make note:
No transom mounted units on full inboards
No plastic units on wooden boats
Higher the freq applies to better target separation in shallow water
Lower freq for the deep water folks.
Garmin:
https://www8.garmin.com/marine/PDF/t...tion_guide.pdf
https://www.youtube.com/watch?v=OyauQTwLioU
Raymarine selection guide: basically the same info here.
http://www.raymarine.com/view/index....id=176&col=197
Just added this page.. A clear list of available transducers and their application etc:
http://www.gemeco.com/transducers-list.php
Hope this helps clear the confusion.