So sorry for your loss! I am enamored with water, so I fly over it a lot. When I shot footage of my parent's pontoon boat, I was too scared to launch off the boat. I launched from the shore to get the boat footage in case a RTH occurred. I almost lost my favorite drone because I miscalculated the battery I needed to return. I landed on "fumes" with the all kinds of alarms going off on the drone. I always dump my footage to a PC at the end of the day because I love reviewing what has been captured.
I'm planning a trip to Maine in October and anticipate flying along the shore. I'm excited and scared at the same time. I will look into getting one of those recovery devices too.
As far as recovering your drone, a wet suit will keep you surprisingly warm in cold water and they can be rented at dive shops. Of course if its over 15' deep, you will likely need tanks and dive gear. If I lived closer, I would be happy to dive it for you because I am open water certified and can rent tanks. But, alas, Kentucky is pretty far away.