I have a West Marine inflatable boat that hold 4 adults and 1 child with a 975 lb capacity. It has a marine plywood floor that gives it rigidity and can withstand fish fins. It is rated for up to 9.9 hp outboard, which is bigger than the space I have to put an OB (also 9.9 hp 4 strokes are pretty heavy). I use a 4 stroke Mercury 5 hp (55 lbs). The boat goes into 2 bags. One smaller one for floorboards and a larger one for the boat itself. Boat weighs about 90 lbs assembled with the floorboards.
A good inflatable boat is pretty durable and has multiple air chambers. It's another option. Was about half the cost of a new porta bote (got it on sale for about $950). I can put the 2 bags in locked storage compartments when not using. Good luck.