Lewis Hamilton: All Aboard the Ass Yacht!

Lewis Hamilton continues to win on land and on sea ... setting sail in Barbados with a bunch of hot chicks in thongs.

The F1 superstar -- sporting a hat that reads "F**king Awesome" -- boarded a yacht with roughly 20 people for a sexy party cruise.

The 32-year-old has been living it up in the Caribbean -- the day before the boat party, he was spotted at the Crop Over festival with the likes of Rihanna and Jeremy Meeks.