That sounds good to me. You might want to try some type of water resistant shoe though in case water gets sloshed on deck. Id hate to be stuck in cold wet shoes! A lot depends on the type of boat youll be on. A big one and you shouldnt have much problem other than some occasional spray. A small one, be prepared to get wet. We were on a big one, so we didnt have any problem. If we did a white water raft trip or kayak trip, we were provided with foul weather gear.
That should be perfect, but also include some rain gear, just in case. You will see shops selling poncho's for $10 around town or find one at home, you just never know with rain, other than that, you should be fine with wearing that.