they were back on the boat, maybe, a half hour. there was not that much difference in his level of intoxication. Natalie fell in the water at about 11:30. RJ did most of his drinking after he noticed Natalie was missing. finstad is going by what lana told her, not by eye-witness accounts.
i do agree with you, though, that alcohol and anger do not mix and alcohol was a huge factor in the scenario but i will never understand why he waited so long to call for help...she was under the influence, could not swim and was petrified of deep dark water. it does not make sense and when something does not make sense it is usually not true. too many missing pieces.