1. I just put a 40 Honda (same size and weight as a 50) on an early 80's vintage (but nicely restored) 16' Crest pontoon boat with smallish pontoons (19" maybe?). The boat is very lightly loaded with just a console, a captains chair, and a couple lawn chairs. Life jackets and emergency equipment were stored in a large tupperware bin. That boat handled it just OK. I would not want to be out in any choppy water with it as it does sit pretty low. Water line about half way up on the pontoons in back.
2. There is no way on earth a boat like this is ever going to see 30mph. Even 20mph is very doubtful. This boat does 15mph on GPS.
If I were shopping for a motor, it would be a 20-30 hp 4 stroke as it would likely be nearly as fast with one of those. My opinion, FWIW.
