WIRING: It's like Christmas lights … once you get a good power source you can really go crazy. I guess that's one of the reasons I've never added a power grid to one of my boats. Sure as I do, I'll have dash lights, bow/stern lights, and an 18" subwoofer (though a pair of 10's would probably work just as well). Once you are set up with a 12 volt system, anything that will connect on a go-boat will now connect in your row-boat. Those are scary possibilities indeed. You'll need to keep the battery stationary, as dry as possible, and make it easy to get at for removal and recharging. The easiest choice would be to mount it in the front hatch area. The battery is actually pretty small, so you won't need a lot of room.
Lower frequency transducers, with longer waves and fewer waves per second, show less detail (larger fish) but carry more energy and penetrate to greater depths. One sound wave at 50kHz is slightly larger than 1", so a 50kHz sound wave will only detect fish if their air bladders are large, slightly longer than an inch. Lower frequency won’t provide as clear of a picture but will operate effectively in the depths of the ocean or Lake Michigan.