Took it out for the first time. Second time ever fly fishing a lake with a float tube. Caught three fish. They were all in the vicinity of where the finder showed a bunch of fish, so I guess it works. Pretty happy with it.
I connected the leash to one of the D loops, on the side of my float tube. I set the leash length just long enough for it to bob around in a ~12in radius. This seems much better than faffing around with mounts, for a regular fish finder.
I used my old backup phone, which has an old/depleted battery. Despite that, it only used about 25% over 3 hours. The unit itself used about 50% of its battery.