Its a long story. The short answer is about 4 hours. It would have been helpful to have the snorkel on the truck instead of up in the attic.
I think the engine still would have died since the battery box was not sealed and the salt water shorted them out. But the engine would not have hydo-locked. It didn't make any noise when it blew, I guess I was distracted by the 135 mph winds. When the storm surge went out there was oil on the ground under the truck and it took me a while to figure out why.
I had the engine replaced, but they apparently did not flush the fuel tank out. It ran fine for a while and finally died out. I have drained the tank and changed the filter and it fired once, but no more. I am thinking injectors and maybe injection pump. I did put a new fuel pump on.
Anybody have any advice?