Generally, hunting dogs today are in two groups: upland dogs and retrievers... generally.
Upland dogs are primarily pointing breeds: German Shorthairs, Vizlas, etc. Retrievers are typically your water dogs: Labs, Goldens, Chessapeakes, etc.
Weimarainers were bred to do both jobs. I've had mine in the field for upland, but never had a desire to try any duck hunting with him. I can tell you one thing, he is the most natural quartering dog you'll ever see. Twenty yards out and back, and out and back, and out and back; all while working a pattern like a clock. And he was never trained to do any of it.
It's a shame I don't hunt much. He's a natural at it.