Foam floats bones dont.
Always duck dive except when you are gunna cop the lip on the head. Just hang on to your board at al cost because if yoiu get pushed deep it will rocket ytou to the surface due to its bouyancy.
Sometimes if the lip lands just in front of you can get what i call the bounce. This is where the lip sort of bounces and all the turbulance is up in the air and you can just pop straight out the back of the wave. You can never tell when ypou will get the "bounce:" as i call it but it works. I have had times where you are scrambling with a mate and he is 1/2 a meter behind you and he ends up copping a flogging and dragged in 100m's whille you safely pop though the back of the wave untouched.
The other important thing to do is keep your eyes open as when your are under water so you can see patches of turblulance and by just moving your head(your body follows) you can dodge patches of twirling water and return to the surface much easier.
The only time i bail is when i cant dodge the lip and it always ends up with getting pushed deep with a long hold down.
Oh well thats my 2cents sorry for the rant