water. if they're in a dry area, the survival time, as long as the air pocket will hold out, if they are wet, again, within one o two hour, they begin to get exhausted. their ability to help themselves will be deteriorating rapidly. but they can survive for up to six hours. >> up to six hours. it's been a while now. what do you do in that situation? because it is probably dark. if you're not familiar with this particular vessel, all you're doing is sort of tapping around in the dark. would people stay put or you suggest they try to figure how to make their way out of there? >> wearing a life jacket, that's going to be difficult. they're going to have to wait for rescue. what they can do is what we call the help position. heat, escape. you try to maintain heat loss from your body. in the help position, basically