This motor bracket will allow you to put up to 110lbs of motor weight on the back. That should be enough to get you a few horse power. Maybe not enough to hydroplane but definitely enough to get around get some fishing done.
Easy to install and capable of pushing a few people around you will find that it is convenient and worthwhile investment. Plug it into the top and bottom brackets and you are all set. Electric and gas motors work equally as well.
You can get a boat for about $300, a Bracket for under $100 and a Motor for $250 leaving you with a new boat $650.