Get your basic obedience rock solid at home, then transition it to the boat.
Be warned; a boat gets small with a young retriever. I have tried to fish with 4 pups thus far and every pup reminds me that I need a pontoon boat and really stupid fish if I want it to work. They have too much energy for such a small space. All mine get/got really excited when I catch/caught a fish and most will try to jump in the water after fish you throw back. They want to be everywhere you are, which gets exciting in tippy skiff where sudden movements will dip a rail. This also puts them right under your feet when you are trying to unsnag a hook or set the anchor, etc. They tangle themselves in anchor lines, snag themselves on hooks and stomp on rods in the process. Taking that out of a pup is tough unless you spend more time dog training than fishing or you get some no-drive fat-ador. Also, they get very hot in a boat, so you need to find a way to provide shade for them. The moral of the story is be prepared to give up on the dream until they are 6-8 years old and it is cool out.
Hunting isn't a problem even for pups because they are usually cold and tired. They just pull hood ornament duty.
Nate