I've got a GT with an 8" Tornado coil that I want to change out to something better. Thought about getting an Ultimate 13" for the Sov, but am told it is not waterproof, and they can go bad, even from using in wet grass. And I had thought they were submersible. 
So what are my choices for good depth and pinpointing, that is waterproof. I may install the Sov control box in a drybod, and chest mount it, as I am likely to wander into the surf with this machine. What do you use?

So what are my choices for good depth and pinpointing, that is waterproof. I may install the Sov control box in a drybod, and chest mount it, as I am likely to wander into the surf with this machine. What do you use?