The Boat

Okay so apparently I have no idea how to take care of batteries. I have never had this much trouble with any battery I have ever dealt with. I have 4 that are not working. I finally bought a new one for the lawn mower but I charged up two of other batteries up and they tested fine(got a tester from fleet farm) and got over to Eagle lake to take the boat out for a shakedown and guess what? It would not turn over. Shoot me now please.