I know nothing really but if it helps, I have two incidental shots of two different setups. Click images to enlarge.

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Attached to the foot brace, I believe a wingnut allowed side to side and angle adjustments. The suction cup noise bothered me so I used the bag of water shown. The transducer cable needed attention at portages.

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Through the hull setup with a ball clamp bracket. Just turn it down/up at portage ends. Worked better (set lower) when my foodpack wasn't the way. Bracket was rather heavy.

Battery pack in both instances was in a thwart bag so a long piece of velcro was used to keep it out of the way when portaging (as usual).

I've never looked so no clue but my wishes? Wireless transducer, batteries IN the unit. Barometer, gps ... i pod touch size - well, plus AA battery pack. Do they need to be so bulky and have buttons?

Don't have any readily available pics of my setup but it's very similar to KF's.  The 'ducer is mounted under the bow seat using silicone and I use cable clips to keep the 'ducer cord snugged up under the gunwales for the run back to the main uit which is mounted on my thwart via a RAM mount.  Convert to 8AA power as KF does.  Keep the battery pack in a ziplock that is attached to the thwart via velcro strapping.  Same velcro strap also keeps the excess 'ducer cable out of the way.

Cable clips:
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I actually use plastic ones that are a good bit cheaper, but you get the idea.  They are pop-riveted to the hull right under the gunwale.

RAM mount:
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Something like this is probably simpler than what I have but was not available at the time.

I use a more standard RAM mount and use a U-bolt to mount it to the thwart with the ball facing me.  I can then just rotate the whole thing down when I portage and back up to paddle.  I like how it puts the depthfinder display higher up so I can more easily keep it in peripheral vision as I paddle.

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I'd like to be able to show you pics of my actual setup but most of the hardware is on my fishing boat which is in storage.  I use the same mount for my other depthfinder on the bow rail of that boat and that's where I last used it.

Also if you own more than one canoe you can save money by just buying extra transducers and permanently mounting one to each canoe.  The actual depthfinder and the rest of the setup transfers easily from one boat to the next.   

Jim,

Not worried about wind in the least.  That cable is clipped in every few inches right along the inner corner between gunwhale and canoe.  There's nothing for the wind to grab.  As for vibration, transducers are designed to handle pretty rough conditions on a fishing boat which I have to think is harder on them than travelling cartopped.

At any rate, I've been rigged this way for a few years with no issues so hopefully that continues to be the case.

Since my one way travel distance to Ely is 1200 miles, I opted for removable; but I also have "snap clips" ever few inches from the unit mounting position to the transducer ... keeps the transducer wire from getting snagged when loading/unloading gear at portages and campsites.  However, I went the epoxy route for mounting the clips rather than pop rivets.  Quite frankly, I didn't want to add more holes to the side of my craft which might potentially weaken the overall structure.  (That's probably being overly cautious.)

dd

Epoxy is another way to go...as is silicone.  But then you miss the fun of drilling holes in your boat!