I use a Musto HPX dry suit, it's intended for offshore sailing. Full Gore-Tex with neck and wrist seals. It works. 100% totally waterproof including standing in boots full of water all day. It's breathable, comfortable, never clammy. I did kayak self rescue training in it, basically swimming and flopping around trying to climb back in a capsized kayak for hours. Only got enough water in one wrist to wet a couple inches of one cuff of the sweater I was wearing under it. I wear a PFD with it, but given experience with the kayak self rescue thing, I would have zero concern ending up in the water with the suit alone.
It's a god send for cold days in an open boat, totally stops the wind. With the hood and a good set of glasses/goggles there's almost no exposed skin. You can inflate it a bit to offer even more wind protection when running.
If you get a dry suit, find one with a very good hood. A lot of them are for white water kayakers and rescue crews who wear helmets. The giant wrap around hood on mine is one of the best features for bad weather and an open boat. Suits designed for sailing would be the place to look.
On the down side they're crazy expensive. The current version of the one I have is $4k. Helley Hansen has one that's a lot less, the Ægir Ocean Dry Suit. I also worry about damaging the gore-tex fishing, hooks, gaff, rod butt chafing the fabric etc.