Here are some cheats and tips for the game Hydro Thunder.
Hidden track:
Highlight the “Back” selection on the options screen before starting
game play. Press Up(2), Down, Up, Down(2), Start to unlock another
track at the track selection screen.
Fishing boat:
Enable all hidden tracks. Highlight the Thresher at the boat selection
screen. Then, hold L + R and press View(2). Select the Thresher to
race in a fishing boat.