Other mistake: In numerous shots modern bobbypins (the white kind brides wear on their headdress) are clearly visible inside the curls of the men's white wigs. For instance, they can be seen when Norrington is reunited with his sword; later when he dies; when Beckett talks about the immaterial becoming immaterial; finally, when he says, "It's just good business," as the Pearl and Dutchman fire on Endeavor. The type of 'hair pin' seen in the wig curls did not exist in the mid 18th century.Super Grover
Other mistake: When Beckett walks through the ship which is being destroyed by cannon fire in slow-motion, you can see things like banisters and railings exploding right by him, and yet no cannonballs are seen, the ship just spontaneously explodes.
Other mistake: After the ship goes over the waterfall, the entire crew is seen crawling from the ocean onto land, completely soaked. However, Mr. Gibbs' beard is completely dry.