At least your dob's know HOW to swim, I spent close to an entire summer at hte cottage teaching a dob to swim - oh what a rough life!
Seriously - doberman's aren't the best swimmers, this one couldn't get it through his head that he needed to also kick with the back legs, all he tried to do was climb up on you to stay up, if you let him "swim" he'd just bob up and sink, sinking more than bobbing.
I finally just grabbed his hind legs and started bicycling with them, then he finally got teh idea, after that, he'd be off the end of the dock right behind me just having a blast.
My current dog doesn't like water too much, you take him swimming and all he tries to do is rescue you, his main concern is always to guide you to shore - go figure, he's part retriever, even has the webbing.....
Although, I'm sure if i threw a squirrel or other wildlife in the pool, he'd be in there in a flash!