The most important thing to remember when mounting the xducer on the TM with any SI or DI unit is the shape of the sonar beam...
The sonar beam is very wide left to right...but very thin front to back...
Try to picture a chinese folding fan opened up directly under your xducer pointing straight down, but perpendicular to the path of the boat....
Turning the xducer with this type of sonar shaped beam xducer can cause skewed images on your screen....
This can be minimized by turning the TM very slowing but you will still have to learn to interpret how the actual images depicted on the screen are relating to the actual bottom....
I think you will love the unit...and post questions on anything ..including how to interpret those images...
Rickie