Hornblower: The Even Chance (1998)

Factual error: When Pellew engages the first French warship, he gives the order to his helmsman, "Hard to Larboard". In the 18th century, helm orders were given in relation to the position of the tiller, rather than the rudder. A helmsman would push a tiller in the opposite direction he wanted the vessel to turn. This practice continued even when a ship was steered by a wheel, so the man at the wheel would have turned the wheel to starboard..except that he didn't.

Factual error: HMS Indefatigable, the cruiser Hornblower is transferred onto, was a razee, a 3rd rate battleship cut down to a heavy frigate. The ship depicted in the movie is no more than a sloop.