While filming in London in October 2010, Johnny Depp received a letter from a local nine-year old schoolgirl, telling him her classmates needed help to "mutiny" against her teachers. He turned up with almost no warning at the school in full Sparrow outfit, but advised against mutiny.
After Walt Disney's chairman of 38 years, Dick Cook was fired, Johnny Depp talked to the Los Angeles Times, and said his enthusiasm for the fourth Pirates movie had reduced after Cook left the project. "There's a fissure, a crack in my enthusiasm at the moment," Depp said. "It was all born in that office." One of the reasons Johnny Depp committed to Pirates of the Caribbean: The Curse of the Black Pearl (2003), was because he trusted Cook, who supported him while "others at the studio were less than enthusiastic about my interpretation of the character, Dick was there from the first moment. He trusted me."
Jerry Bruckheimer gave strict instructions to casting directors that actresses auditioning for the mermaid roles must have natural breasts. During shooting of their scenes, they were not allowed outside until dusk, in order to avoid spoiling their make-up.
Penélope Cruz was pregnant throughout production, but it wasn't noticeable until September 2010. As Penélope's baby bump grew, it caused difficulties in wardrobe, so the producers enlisted the help of Cruz's younger sister, Mónica Cruz. According to reports, Penélope filmed the close-up shots, while Mónica doubled for her in the long-distance scenes.
As Jack enters the Santiago, the camera flashes to a skeletal Ponce de León laying on a bed, surrounded by treasure. This is a reference to the Pirates of the Caribbean ride in Disneyland where guests see a skeletal pirate Captain laying in bed, surrounded by treasure.
When making Pirates of the Caribbean: The Curse of the Black Pearl (2003), the scriptwriters revealed that they placed the story in a thirty-year environment set loosely between 1720 and 1750. They also said that they did not intend the films to be entirely historically accurate. However, it was revealed that this movie takes place in 1750.
This was the first film to be released in the 4DX format in Mexico and in the Western Hemisphere, which is only available at select Cinépolis theaters. 4DX features strobe lights, tilting seats, blowing wind and fog and odor effects.
The film budget had to be scaled down to no more than two hundred million dollars (the Pirates of the Caribbean: At World's End (2007) budget was three hundred million dollars). This was mandated by studio president Rich Ross (who replaced the fired Dick Cook), in addition to the then 2008 economic slowdown in the U.S.
Blackbeard's ship, The Queen Anne's Revenge, is actually a modified version of The Black Pearl, one of the vital ships in the series. The Sunset, as it is called in real-life, was used in the latter two parts of the first three, and in 2010 redesigned to portray the Queen Anne's Revenge in this installment. The biggest change was above deck. The back was cut off to deck level, and rebuilt again in two stories.
Blackbeard says that his quartermaster sees things before they happen. This is an oblique reference to the character of Fedallah in the novel Moby Dick, the source of various prophecies about the death of his Captain.
Oren Aviv said Disney had chosen to scale this movie down from the former in the series; "It's important to get the story right and it's important to me to scale it down, because we can't get bigger. The movies have subsequently gotten bigger and bigger and very complicated and they were satisfying on so many levels obviously, but I want to kind of reboot the whole thing and bring it down to its core, its essence, just characters." He agreed that there is a lot of Captain Jack Sparrow's back story that we haven't seen yet without confirming or denying that we might see some of that in the fourth movie.
Barbossa's ship, the Providence, was portrayed by the H.M.S. Surprise, part of the collection of ships of the Maritime Museum of San Diego (www.sdmaritime.org), where it is open daily to Museum visitors. To sail the ship during the filming, Disney hired a crew from among volunteers and staff of the Maritime Museum. Surprise is a 179 foot full-rigged ship. She was built in Nova Scotia in 1970, from original Admiralty plans for the 1757 British 24-gun frigate H.M.S. Rose, for which she was originally named. The ship was purchased in 2001 by 20th Century Fox, and modified to serve as the H.M.S. Surprise, under the command of fictional Captain Jack Aubrey in Master and Commander: The Far Side of the World (2003). The Maritime Museum of San Diego purchased the ship from Fox Studios in 2004, and retained her movie name. In both of her names, the prefix "H.M.S." (meaning Her (or His) Majesty's Ship) is an honorary, rather than an official designation, since she does not hold a royal warrant.
This is the first "Pirates" film that does not have Jack oppose a crew altered by supernatural circumstances. Barbossa's crew being un-dead in "Curse of the Black Pearl" and Davy Jones' being fish-people and serving him to escape death in "Dead Man's Chest" and "At World's End".
When Phillip (Sam Claflin) is tied up to the mast, a pirate says to him, "Either you're with us, or against us." - echoing former President George W. Bush's quote in the aftermath of the 9/11 terrorist attacks.
At 50:59, after Blackbeard practices Voodoo magic on Jack Sparrow, it can be seen that a wound has been marked on his skin. Although some say it is the "Trident of Poseidon", there are very obvious similarities to think that it is rather a tribute to the video game "Quake" by some artist of the team.
The trivia items below may give away important plot points.
The outdoor entrance to the Fountain of Youth, is the Waikapala'e Wet Cave on the north shore of Kauai. Analogous to the film's magical watery passage to The Fountain of Youth, the cave holds a real submerged (depending on water level) passage, through which explorers can travel, in order to reach an isolated chamber known as "The Blue Room." Some Hawaiians tell of an actual pirate treasure found hidden in "The Blue Room" by the original discoverers. The pirate treasure (if it ever existed) is gone, but the cave and chamber remain a natural treasure, still accessible to intrepid explorers.
Despite a common theory, Angelica is not the second woman to be a Captain in the "Pirates" movies. Elizabeth is the only woman to do this in the previous movie. Angelica posed as a Captain, but on the Queen Anne's Revenge, Blackbeard is the Captain, and Angelica is his first mate. She did not take over after his death, as a first mate would normally, because the ship and crew were claimed by Barbossa. Also, one of the pirate lords from Pirates of the Caribbean: At World's End (2007) is a woman.
Captain Jack Sparrow impersonates a judge under the name "Smith" in order to save Gibbs from being sentenced to death. In The Curse of the Black Pearl, Jack also begins the film under the fake name "Smith" as he pays to dock his sinking boat and talks about the Pearl.