12' is the longest pontoon boat that can be loaded by one average size person. 8' boats are the best all around personal fishing craft for average size people who fish in lakes and moderately fast streams. 10' boats are best for larger than average size people who fish lakes and moderate streams or average size people who fish fast steep rivers. 12' boats are mandatory for 2 people or very large people or people who want to haul a lot of gear in rough water. 10' and 12' boats are hard for average size people to propel with fins on a lake.
Common sense is the mother of comfort and survival.