FWIW It may be better to mount the transducer toward the front of the canoe so that you see where you are going and not where you have been. In a practical sense I'm not sure this is actually accomplished considering the short time delay between data gathering and display but if the transducer is mounted in the back you will definitely be looking at what you have already passed over.
It would be wary of mounting the ducer both too far forward and right on the centerline, in other words the thickest parts of the hull. There is too much possibility of a stray bubble in the resin. Bubbles in the resin of the hull or the silicone or whatever the ducer shoots through must be avoided to get good results. Most successful mountings I've seen are under the bow seat.

Good advice KF.  Thanks.  With the silicone mount it is relatively easy to change the location of the transducer as it peels off with little effort.  I think I'll move it under the bow seat.  I should mention that my canoe doesn't have a gel coat on the inside so to make the surface smoother I first laid down a thin coat of epoxy.  Here's a decent video for installation.  (You need to Login or Register to view media files and links)

I have installed several and have found a simple method that has worked.  Set my canoe on a piece of carpet on the garage floor. Then clean a spot on the bottom inside of the canoe where I want the transducer with alcohol.  Place a spot about 3/8 inch in diameter and ¼ inch deep on the transducer bottom of GOOP or RTV.  Then press it into the location where I want it mounted and place a heavy (10+LB) weight on it for a day.  A trick to get RTV to set well is to put it in place then pull it off and exhale on both surfaces and put it back on.  RTV requires moisture to set and your breath has enough.  Usually these can be removed by working a flexible thin blade under them.

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Here's the story:

I ordered my depthfinder from TheNerds.  The depthfinder was mailed directly from Humminbird Company.  It arrived lacking a key part.  I was told by the Hummingbird company rep that I had to mail the defective part back to Humminbird to get a replacement. 

I wrote TheNerds of my frustration over having to spend another $10 in postage to mail the defective part back. 

In response, they refunded my original postage and handling charges!  They did this, even though they were not responsible for the product problem. 

Impressive customer service.

prouboy

The model above this one sends out a probe, finds and grabs the fish selected and returns to the boat with said fish.