Yeah...normally I would be right on with that...but I checked that area for commercial flights -- 2 per day @ 35,000 feet. That's not a lot to hope for. There are also no military flights flying in that area (figure 800+ miles west of Peru). Helicopters won't go out that far. There are no shipping lines through that area...they all travel great-circle route north of there.
When I asked the Kon-Tiki museum if they thought the men on Kon-Tiki would have been rescued had they lost sail power--they laughed. They said, "if they had lost the sail they would not have been rescued by another vessel. They would have had trouble holding the course but if they had been lucky, then they would have moved with the current and got there alive."
There's just no one out there to signal to. Better off having extra water and hoping you are in the current.
Gene