I don't have a PFD for my lab, but he is very well behaved and sits right next to me when we are on plane. If he wants to stand in the wind, I'll hold his leash or push his butt down to sit. At Castaic, he'll jump and swim to shore when fishing the coves and banks if given the okay (Good boy haha) and will always stay in sight and return on call.
Every dog is different though. I let mine swim, but always monitored like a child. It's all about controlling the pup and keeping everyone safe. Take baby steps.
My pup is well behaved on and off the leash as well as potty trained. To get him on the boat I started with the letting him stick his head out of the car window. Then sit in the truck bed. Then the Lagoon and finally Upper Castaic. During the training, the leash was always on the collar. In the truck bed, ratchet straps secured the leash. On the boat the leash was always on when on the move.
Hope this helps. It's always cool having a pup on board.
ProTip: Keep grocery bags (for accidents), food, water, and a chew/ rawhide/ tennis ball.