I think the concept is ok, but yeah, you could get lost (like, I wonder what happens if I don't see the boat at all and start moving?), but I think that's part of the point, I just hope it doesn't break the game if you do get lost or start travelling in the wrong direction (I actually saw the boat and didn't change course haha, so I got to land safely).
I believe some more events would be nice. The tension remains mostly the same throughout the whole travel.