He's said he was even chased for a time by pirates off the coast of Indonesia and thought he'd be killed.
Sunderland keeps in touch with his parents for moral support and gets weather updates over a satellite phone to help him avoid catastrophe.
One unexpected surprise for the Sunderland family: the financial burden of the trip. So far, the trip has cost $150,000, which Sunderland hopes to recoup with a book and possibly his own documentary.
A lonesome life at sea is something most teenagers would avoid. Sunderland said he has filled his free hours when he's not navigating the ship by listening to one CD on repeat, learning to play the didgeridoo and reading.
What will he do after he gets home? His biggest worry is how to adjust to life in the normal world.
"It's just going to be kind of weird when I get back -- not having another horizon, another sea to cross," he said.
Sunderland doesn't plan to sit still for long. He dreams of conquering Mt. Everest, though he may have to finish high school first.
For more information on Zac Sunderland and his voyage, visit his website.