When Captain LaRochelle jumps from his burning ship, he is wearing a white shirt, but when subsequently brought aboard the Sheba Queen his shirt is green. Moments later when he enters Anne's cabin he is wearing yet a different shirt (sleeves hanging over cuffs) and a narrower cummerbund.
Red Dougal (James Robertson Justice) falls face down over cannon after being hit by part of a falling mast. A moment later he's seen face up over the cannon.
The direction of the rowing boat when Captain Blackbeard leaves the beach with his escort. (Orientation changes too fast between shots hardly changing the position of the boat.)
During his pursuit of the Sheba Queen, Captain LaRochelle addresses his grumbling crew. The close up of him shows his neckerchief in a very different position to that shown in the fuller length shots immediately before and after.