Are you aiming to make yourself unconscious/barely conscious? Yes, it's been done before successfully. It staves off the panic, the body really isn't good about waking you up as you inhale water, provided you're blacked out enough. Any body of water located near a bar tends to attract drunks who fall "overboard" and go out without much of a fight.
That being said, if this truly is your method, depth and proximity to a rescue site maybe an issue, going without oxygen can obviously cause brain damage and you wouldn't want to get revived with 3 brain cells left because the waves took you back to shore.