No reason you can't do that. There are higher powered in hull 'ducers that will do what you want as well. The Airmar/Furuno B260 series comes to mind. Not cheap though. If you got the though hull route, make sure you get one that will do what you want; just being a through hull does not guarantee that. You should ask Furuno what they recommend for your new unit and what you want from it, they are very helpful.
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"