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?