As far as the captains license logged dives do not count towards your hours required & being a licensed captain is very high liability job. You need lots of experience operating all types of boats & electronics as well as knowing how to trouble shoot problems of all systems. Anybody can drive a boat in open calm water but docking & high seas can become very dangerous quickly. It is far more stressful than you can imagine if you are not ready also when moving other peoples boats they are not always properly maintained.