The author includes a pair of graphs on page 141. His claim is that while a person not drinking water loses conciousness around the 4th day, a person drinking seawater would lose conciousness around the seventh day. In both cases, a person would die around the ninth day.

The author states that "Recent experiments" show that seawater can be consumed that way. He references a "Naufragé volontaire" by Alain Bombard as a source.

I'm quite skeptical of this drinking sea water stuff, too.