Surf : How to do the duke diving, or chicken dive

Duck diving is the safest way to get through waves, but some times the waves are
too big to duck dive. In this case, another strategy is to dive under the wave
without your board.
The first thing to consider when you are going to ditch you board is people behind
you. A loose board can seriously injure someone so if there is anyone behind you,
even if the wave is too big you must attempt a duck dive.
After ensuring no one is behind you, wait until the wave is a couple of meters away
before swimming as deep as possible under the water. Stay under the water until
the wave has completely passed.
This is not a recommended method of getting through a wave.