My through hull xdcr is 0 degrees even though it is left of center by about 1 foot. Probably doesn't make much difference since it pretty much agrees with the charts where I sail.

Here are some early install pictures of the TackTick (Airmar made) transducers when I did the upgrade. Bottom view was before bottom painting.

Right of picture is forward on boat.
[Linked Image from j30.us]

[Linked Image from j30.us]