Has anyone dumped with their sonar? Did it still work?

The current units from Garmin, Lowrance, and Humminbird all carry an IPX7 rating, which means they're supposed to be able to withstand submersion at a depth of up to 1 meter for up to 30 minutes, so any of those *should* be fine. You'd want to thoroughly dry out any electrical connections before you tried turning it back on again, and whether your battery survives is another matter entirely, but the sonar unit itself at least should survive a dunk - provided you can catch it before it sinks to the bottom.