Continuity mistake: While Jack is inspecting the crew on the dock at Tortuga the sun shines from different directions in some shots. In some shots the crew's back is in shadow and in others their right side is in shadow. Also seen with the shadow of the goods in front of them, behind them, and to the left of Anamaria. This scene was shot during the course of a day. (01:01:00)
Continuity mistake: As young Elizabeth sings, the next shot from behind her to her right we see the cannonballs lined up at the bottom of the rail going around the deck. When she yells out, "Look! A boy..." Now there is a cannon in the corner of that bow. (00:00:45 - 00:02:20)
Continuity mistake: When Jack is being locked in the brig, he has something black on his hands when on deck, but as he is being locked away, they are clean. (01:17:00)
Continuity mistake: At the end of the movie when Will saves Jack you can see a blue sky in midday, yet when he kisses Elizabeth a few moments later, the sun is setting with shades of orange and yellow. The next scene (last scene in the film) we see Jack on the Black Pearl and the sky is clear blue again.
Factual error: After Will And Jack commandeer the Interceptor, the ship is viewed from above, sailing on a beam reach (a point of sail in which the boat is at 90 degrees to the wind). When Jack knocks Will off the ship with the boom, he jibes the boat, causing the sail to shift positions suddenly. In order to do this from the previous position, he would have had to turn the ship almost completely around. This would have taken well over a minute. Jack did this in less that three seconds. The sail is also filled to the wrong side while it sweeps Will off the deck.
Continuity mistake: When Elizabeth's maids lace up her corset, obviously both the back and front laces were pulled very tight, as this is the reason for her discomfort and eventual lack of air. After Jack rescues her, as she is on his shoulder we see the two sides on the back of her corset are far apart and the laces in between extremely loose. Yet, when she is lying on the dock, Jack slices the front laces on her supposedly constricting corset so she can breathe again... (00:16:25)
Continuity mistake: While rescuing young Will, as Norrington shouts, "Man overboard! Man the ropes. Fetch a hook," Governor Swann is leaning over the starboard rail near the rigging throughout these shots. However, as Norrington says, "Haul him aboard," in this one shot Governor Swann's body is then seen on deck rushing to the rail with other sailors, where he already was in the previous shots. Also, a moment later the ribbon on the sailor hat lying on the tarp changes position in a following shot. (00:02:25)
Continuity mistake: As Jack and Will duel, the amount of closed buttons on Will's vest changes. After Jack says, "And now you have no weapon," three buttons are closed. When Jack says, "You need to find yourself a girl mate," four buttons are closed. Then up on the beams, in one of the first shots, there are three buttons closed. Coming off the beams, hanging upside down, four buttons are closed again. (00:24:15)
Factual error: Viracocha is sculpted on the "Aztec" chest of golden coins, but is not an Aztec god.
Revealing mistake: Keira's stunt double Sonia is obvious in different shots throughout the film. When Elizabeth walks onto the deck of the Pearl, only to see the skeletal pirates, she stumbles backward and lands on the tarp, and it's very apparent that the one who comes back down from mid-air onto the tarp and goes back up is Sonia. Later on Isla de Muerta, Elizabeth whacks Jacoby (burning beard) with the gold rod and soon after she approaches a second pirate. This pirate is very pleased with himself when he takes the gold bowl off his head, and we can then see it is Sonia actually whacking him, but in the very next shot it is Keira reacting to whacking the guy. (00:59:05 - 02:00:05)
Continuity mistake: At Isla de Muerta, whilst floating offshore in the rowboat, when Jack moves forward to sit beside Norrington and discuss the plan, Mullroy sits behind Jack. In Murtogg and Mullroy's close-ups the silver medallion on Mullroy's white strap is centered properly at his chest. However, in other shots that silver medallion is near his waist.
Continuity mistake: When Port Royal is being attacked by the pirates, Will throws an axe into Jacoby's back. The axe handle lies flat against Jacoby's back. In the next shot, when Jacoby is lying on his stomach, the axe's handle is sticking up, perpendicular to his back, making it easy for Will to run by and grab the axe quickly. (00:31:15)
Revealing mistake: When Will uses skeletal Jacoby's sword to skewer the other skeletal pirate, he runs behind Jacoby to avoid being slashed and ducks. However, as Will looks at the pirates, his eye contact with the two skeletal pirates and their weapons is not in sync with them. Since they are CG, they were not there during filming, same as the shot of the three skewered pirates. (01:56:35)
Visible crew/equipment: After Will tells Elizabeth he loves her, she sees Mr Cotton's bird, then says, "I can't breathe." In the next shot, when the camera faces Jack on the gallows, the soldier on the right of the screen steps away from the wall. Very small in the corner, at the far end of the courtyard, you can see a crew member wearing a light blue shirt and cap. (02:06:10)
Continuity mistake: As Will first walks through the crowd at Jack's hanging, there is a wide shot. Then there is a semi close-up of Will and the surrounding people. Next there is a shot taken from behind Will, still showing some people around him. In all three shots as Will stands still, some of the people's positions differ and some of the people are different, in all three shots. (02:04:40)
Revealing mistake: After Barbossa shouts, "They're clubhauling," in the wide shot of Interceptor, the seven men on deck are very obviously not Jack's crew. Even the one dressed as Will does not look like him. (01:24:50)
Revealing mistake: Three shots after Ragetti inserts his wooden eye at the Port Royal shore, two pirates, one with long hair wearing a cap and one bald, each holding a torch in their right hands, are running and screaming. In the background, the pirate who is sliced in the belly by Will in the later shot, is seen running forward towards Will, who's partially seen on the left in the background, but Will has NOT even left the blacksmith shop yet and the woman running in the background has had her dress' color altered so as not to resemble herself in the later shot. We see the two screaming pirates later in the foreground of the same shot, before Will crosses the sword and axe overhead. (00:30:55)
Factual error: Near the start, Jack steps from the yardarm of the sinking craft onto the dock. However, as it is a sailing craft, there is no way that it could have continued its forward movement once the sail was under water, even discounting the drag effect that the sail would have had in the water. Once the sail is submerged, it would act as a type of anchor. (00:10:00)
Continuity mistake: After the scene in Tortuga, there is a shot with the moon, really big. The boat passes in front of it with a pan and when the boat travels further on screen, you see the moon again in the front, very small. The shot made it look like there are two moons. (00:54:00)
Continuity mistake: Aboard the Black Pearl, when Jack is speaking with Barbossa in the Captain's stateroom, Jack takes a bite out of an apple, close to its stem, with the stem at the top. However, in the following shots, particularly when Barbossa and Jack are on deck, the angle, position, and appearance of the bite mark differ between shots. (01:20:25)
Answer: The curse needs the blood of everybody who took a coin from the chest. All the other pirates have already contributed so, as the movie opens, the only blood needed is Will's, substituting for his father. During the finale of the movie, Jack takes a coin from the chest, adding himself to the curse, so his blood is now required as well as Will's.
Tailkinker ★
But I didn't see any blood on the coins, and none of the pirates cut themselves, even before Will became part of the mix.
Yes, the other pirates did cut themselves before Will came into it, off-screen. The lack of blood on the coins can simply be explained as most of it dripping to the bottom of the chest, it being washed away by storms blown into the cave, or by the fact that they didn't drop that much blood on it in the first place.
When they had Elizabeth they believed she was Bill Turner's daughter, but they all thought the curse had failed, none of them had cut themselves so it makes zero sense.
They had been collecting back the coins for years. During that time they repaid their own blood. All they needed was the last coin and the blood of Bill Turner to break the spell.
lionhead