You may have read by now the official lie about this treatment, which is that it “simulates” the feeling of drowning. This is not the case. You feel that you are drowning because you are drowning—or, rather, being drowned, albeit slowly and under controlled conditions and at the mercy (or otherwise) of those who are applying the pressure. The “board” is the instrument, not the method. You are not being boarded. You are being watered.
Christopher Hitchens on being water boarded. You can follow the link to see him tortured.