It turns out that you can't: waterboarding really is drowning. The torturers just stop it before you die; depending on their purpose, maybe before you pass out, maybe after.
Waterboarding is not a simulation. Unless you have been strapped down to the board, have endured the agonizing feeling of the water overpowering your gag reflex, and then feel your throat open and allow pint after pint of water to involuntarily fill your lungs, you will not know the meaning of the word.
Waterboarding is a controlled drowning that, in the American model, occurs under the watch of a doctor, a psychologist, an interrogator and a trained strap-in/strap-out team. It does not simulate drowning, as the lungs are actually filling with water. There is no way to simulate that. The victim is drowning. How much the victim is to drown depends on the desired result (in the form of answers to questions shouted into the victim's face) and the obstinacy of the subject. A team doctor watches the quantity of water that is ingested and for the physiological signs which show when the drowning effect goes from painful psychological experience, to horrific suffocating punishment to the final death spiral.
- , a former chief of training at the Navy SERE (Survival, Evasion, Resistance and Escape) School.