Help picking correct boat

[Heymate]

Hi all, I need help, I will be fishing and scuba diving with my wife and two girls, around stradbroke island off Brisbane, and other similar areas, I have a v6 front wheel drive, want something big enough so the girls feel safe, but small enough so I can get it on and off at boat ramp. I'm thinking 4.5m with a 70hp? Please help