I really, really dont want to learn the hard way 
I have a service contract from neary media so i can get it repaired if it get dunked in water for free, so im not extremely worried about breaking the actual electronics inside. What I am worried about is how long the P4 floats for. Do I have 10 seconds, 1 minute, 5 minutes... or is there some cheap way I can get it to float without effecting the aerodynamics much? I fly over water on a daily basis so this is why I am worried. I recently almost had it crash into water while RTHing, so I am already concerned

I have a service contract from neary media so i can get it repaired if it get dunked in water for free, so im not extremely worried about breaking the actual electronics inside. What I am worried about is how long the P4 floats for. Do I have 10 seconds, 1 minute, 5 minutes... or is there some cheap way I can get it to float without effecting the aerodynamics much? I fly over water on a daily basis so this is why I am worried. I recently almost had it crash into water while RTHing, so I am already concerned