I want my belly button pierced!! help!?!?

Okay, I am 14 right now, will be turning 15 in Oct... I really want my belly button pierced and my mom said she would pay for it and sign the papers, but there is a problem: my dad has custody (not my mom) and he says hells naw..... How do I convince him to let me have it pierced? My mom was going to get it pierced over the summer and have me hide it from my dad, but I know that means no swimming and I have never owned any bathing suite except a bikini, so if I make it until next summer without him seeing, I'll get caught then and in HUGE trouble! My dad is waaaayyyyy over protective and a HUGE control freak, but I have 5 piercings in my ears... 2 on the bottom of each ear and the other is a cartilige piecing..... Any ideas of how to convince him to let me get my belly button pierced?? Please help! :) Any help will greatly be appreciated and I would also appreciate it if ALL rude comments were kept to yourself :) thanks everyone :)