Ahhh I remember when I was was your age
I think it would be prudent to finish your HSC then get a degree or similar to fall back on before you started up a charter business, I bet I sound like your father now.
Seriously though if I were starting one up esp on the Gold Coast I learn to speak Japanese or Chinese and advertise my services in fishing magazines over there.
As you live on the Gold Coast why don't you try and get a part time job as a deckie on a charter or game boat, you'll soon learn if it's you or not.
Cheers
Mike