If this voyage was done without instruments on the boat then I stand corrected - that is indeed impressive. But it also inspires me to read the material on it because I have reservations.
An example of them is that when he got south of Australia he suddenly turns left and sails straight up to a landfall. This after sailing for at least a month, probably more, completely out of sight of land. I wonder what it was that let him believe that by turning left he was in line with a port on the Australian coast. Remember the claim that he had "an hour glass as his only navigation instrument "
The course that is shown on the chart actually could not have been done better with all the instruments that modern science can muster. Many of the single handed racers that have the best instrumentation and comms that money can buy would be proud of sailing a course this good.
I'm not yet convinced.
The hour glass was used just to keep fair, the amount of time each person was on watch, period.
As to the Left turn that brought Marv into the port in Australia, it was a dead North turn. He is a
celestial, solar, wind, water current, etc, navigator. The sun comes up in the East, so he turns Left
hence North to head to Oz. How did he know when? Maybe Last night he had the stars to look
at and he knew where he was on the surface and decided he wanted to go further east, but maybe
not a full 24 hours worth of nau-tical miles. So, next day at high noon they made the north turn.
The man made this voyage to prove the ancients could navigate all over the salt water limitlessly. I'd
love to repeat his journey.