Goofs

Edward Pellew is portrayed as Sir Edward Pellew who is already captain of HMS indefatigable in February 1793 when the French declare war on Britain. In reality, Pellew was not knighted by King George III until the end of 1793 and despite already having a distinguished service record in the American Revolutionary War, was a half-pay Captain working his farm in Cornwall at the time war with revolutionary France was declared and Sir Edward did not take command of HMS Indefatigable until 1795.

When they are supposed to be stranded in a ship's boat in the Atlantic, out of sight of France, reflections of the sea appear to some as land visible behind the French captain of the Marie Galante when he and Hornblower stand-off with guns just before the Indefatigable is sighted. Closer inspection shows the waves and not the coastline.

Whenever a cannon is fired, there is hardly any recoil whereas a real gun would fly back at least six feet immediately. This is a result of using enough powder to have a muzzle flash, but not produce any recoil. This was corrected in later movies in the series by having the guns move back the proper distance when fired.

During his speech to HMS Indefatigable, Captain Pellew says, "For there is no power on earth that can withstand the might of the British Navy!" It is properly called the "Royal Navy", and was so since long before the Napoleonic Wars. A captain would not likely have made that mistake.