When Peter Blood visits the two doctors in Port Royal, he puts his hat on one of the doctors' desks on the side furthest from the door. When he leaves, he walks to the door without picking up the hat, and as he turns at the door, his hat can still be seen on the desk. But in the same shot, his hat suddenly appears on his head, and he doffs it to the doctors before walking out of the door.
When governor Steed receives treatment from Dr. Blood, Steed holds the cane beside the armchair in the establishing shot. In the next shot, the cane is between his legs.
When Blood and Levasseur are shooting coins, a single bullet hole can be seen in the ceiling following Blood's second shot. The next time the ceiling is shown, before any more shots are made, there are three bullet holes in the ceiling.
When Arabella Bishop's ship is spotted by Blood's ship, the lookout yells "ship to the port bow!" Capt. Blood, in his stern cabin, rises and walks to the rear windows and looks to the starboard side aft, where he sees the ship.
When Blood is discussing his escape plans with Drs. Bronson and Whacker, the end of his belt is out of the buckle. A few seconds later, it is neatly tucked in.
The film is set in 1685 and refers to Philip being the king of Spain. Carlos II was king of Spain at this time.
The Spanish pirate ship is shown flying a flag similar to the modern Spanish flag. The earliest use of this flag was 1783 for naval purposes, well over one hundred before the time shown. The correct flag for the time of the movie would be the Cross of Burgundy.
Ships fire broadside from their sides. Sailing between to fire is not a wise tactic. Being behind them and turning broadside would allow Captain Blood to not get hit, as well as to be able to sink both ships from hitting them in the bow multiple times without risking his men or ship.
(at around 1h 11 mins) Text on the screen states, "Tortuga ..... Capitol of an easy-going Colonial Governor..." The correct word for the seat of government is "capital"; a "capitol" is a building.
Levasseur's eyes blink after the second wave has passed over his dead body.
When Arabella Bishop is on the ship returning from England, she sees another ship in the distance, but the shot of the other ship was taken from land, not from the ocean, as waves can be seen starting to break in the near foreground of the shot.
During most of the scenes on the ship, the "water" and "clouds" in the background do not move, showing the scenes were shot inside on a stage.
Capt. Blood orders his men to board the second French ship after destroying the first one. As Mr. Pitt (Ross Alexander) jumps from one ship to the other, he strikes a French sailor with his musket. As he does so, the "wooden" stock of the rifle is wiggling about revealing it to be made of rubber.
The courtroom scene is introduced by a shot of the royal coat of arms, in the form adopted in 1837. In the next scene, a window in the palace shows the shield correct for 1603-1707, reflecting the claim on the crown of France first made by Edward III of England in 1340.
During the final battle, Captain Blood's ship hoists a Union Jack flag, which was not in use until after the Act of Union in 1701. The scene takes place in 1689 (shortly after William III and Mary II take the throne). The correct flag would have been the Cross of St. George (red cross on white background).
The Spanish privateers are noted as sailing under the 'gold and crimson' of the Spanish flag. However, Spain did not adopt a flag in gold and red until later into the 1700s, years after the film's setting.
During the last battle, the overhead shot of the French ship has the officers and crew in early 19th century uniforms.
When Arabella Bishop is about to take ship for England, she is carrying a small dog, a Pekingese. The Pekingese was unknown outside of China until the late 18th century, while the movie takes place in the 17th century.
When Blood and Levasseur are shooting coins on Tortuga, smoke can be seen rising from Blood's pistol before the gunshot sound is heard.
When Bishop is tossed over the side of the ship, support wires are briefly visible.
After Blood and his men take over the Spanish ship, Col. Bishop comes out to congratulate the men who saved the town. After coming on board ,he sees the chest with the ransom he supplied.
How that chest came on board is not known as Blood fired on the Spanish boats returning from the town with the ransom.
No gunner, whether aboard ship or on land would place his foot on a gun carriage due to the recoil - it's a sure way to break a leg; yet the gunner. Hagthorpe (Guy Kibbee). does it a couple of times.