Historical inaccuracies
The film's story and characters are fictional. The film sparked controversy during its production and release. Anger over the film's inaccuracies reached the House of Commons. Labour MP Brian Jenkins used Prime Minister's Questions in June 2000 to state that the film was an "affront to the memories of the British sailors who lost their lives on this action." Prime Minister Tony Blair said, "I agree entirely with what you say... we hope that people realise these are people that, in many cases, sacrificed their lives in order that this country remained free." Paul Truswell, for the constituency of Pudsey, a town closely associated with HMS Aubrietia, wrote to the US president Bill Clinton, who acknowledged that the film's plot was only a work of fiction. The director of the local Horsforth Museum lamented the rewriting of history, saying: "You can't rewrite history and we have to pass on the facts to the younger generation through the schools." In 2009, the film was first on a list of "most historically inaccurate movies" in The Times.
Sub Lt. David Balme, the Royal Navy officer who led the boarding party on U-110, called U-571 "a great film" and that "young people will love it" and said that it would not have been financially viable without being "americanised". The film's producers did not agree to his request for a statement that it was a work of fiction, but the end credits dedicate the film to the "Allied sailors and officers who risked their lives capturing Enigma materials" during the Second World War. The credits acknowledge the Royal Navy's role in capturing Enigma machines and code documents from U-110, U-559 and the US Navy's capture of U-505.
Author Hugh Sebag argues that while the media may have made reports on the fact that the British made the most crucial captures, the Americans role was also unjustly downgraded, noting that they made an important part in breaking the Enigma code. However, in 2006 screenwriter David Ayer expressed regret over making U-571, stating that the film had distorted history, and said that he would not do it again. He told BBC Radio 4's The Film Programme that he "did not feel good" about suggesting that Americans, rather than the British, had captured the naval Enigma cipher: "It was a distortion...a mercenary decision...to create this parallel history in order to drive the film for an American audience. Both my grandparents were officers in the Second World War, and I would be personally offended if somebody distorted their achievements."
The first capture of a (five-cylinder) naval Enigma machine with its cipher keys from a U-boat, designation U-110, was made on 9 May 1941 by HMS Bulldog of the Royal Navy, commanded by Captain Joe Baker-Cresswell assisted by HMS Aubrietia and HMS Broadway, seven months before the United States entered the war. The United States's involvement in the European theatre of the Second World War did not commence until mid-1941 with Lend-Lease, and direct, open participation did not begin until the US Navy began engaging the Kriegsmarine in the fall of 1941, months before Pearl Harbor, by which time Enigma machines had already been captured and their codes broken in Europe.
In 1942, the Royal Navy also seized U-559, capturing additional Enigma codebooks. According to Britain's Channel 4, "the captured codebooks provided vital assistance to British cryptographers such as Alan Turing, at the code-breaking facility of Bletchley Park." The Allies captured Enigma-related codebooks and machines about fifteen times during the War. All but two of these by British forces, the exceptions being the Royal Canadian Navy capture of U-744 in March 1944, and the US Navy's seizure of U-505 in June 1944: by this time, the Allies were already routinely decoding German naval Enigma traffic.
The actual U-571, captained by Oberleutnant zur See Gustav Lüssow, was never involved in any such events, was not captured, and was in fact lost with all hands on 28 January 1944, west of Ireland. She was hit by depth charges, dropped from a Short Sunderland Mk III flying boat, EK577, callsign "D for Dog", belonging to No. 461 Squadron, Royal Australian Air Force (RAAF) and based at RAF Pembroke Dock in Wales. The aircraft's commander, Flt Lt Richard Lucas, reported that most of the U-boat's 52 crew managed to abandon ship, but all died from hypothermia.
The film portrays the U-boat sailors machine-gunning British merchant crewmen of the ship they sank; although Wassner clearly dislikes giving the order, and some of his men are just as unhappy as he is, Wassner argues that because the boat is so badly crippled, short on crew members and supplies, with sensitive information aboard, it is too risky to leave the British survivors to possibly report the U-boat's position. The shooting of survivors could also be seen more as mercy killings rather than leaving them to die. As shown later with Tyler and his crew keeping Wassner alive; sabotage is a possibility as well. In reality, U-boat crewmen are far more often known to have assisted survivors with food, directions and occasionally medical aid. Such assistance only stopped after Admiral Karl Dönitz issued the "Laconia order" following a US air attack on U-boats transporting injured survivors under a Red Cross flag in 1942. German U-boat crews were thereafter under War Order No. 154 not to rescue survivors, which parallelled Allied policy. Afterward, U-boats still occasionally provided aid for survivors. In fact, out of several thousand of sinkings of merchant ships in World War II, there is only one verifiable case of a U-boat's crew deliberately attacking the survivors: that of U-852 after the sinking of the Greek ship Peleus in 1944.
The real USS S-33 was stationed in the Pacific Ocean from June 1942 until the end of the war. She was sold for scrap in 1946. When Lt. Cmdr. Dahlgren orders Lt. Tyler to take down the captured German U-boat, he cries out "Take her down!" These were the last words of Lieutenant Commander Howard W. Gilmore who posthumously received the Medal of Honor for his self-sacrifice in saving his boat, USS Growler (SS-215). Mazzola mentions that S-26 sank in a test dive. The real S-26 did not sink in a test dive, instead sinking in a collision with a patrol combatant, PC-460, in January 1942.
The Kriegsmarine destroyer Z-49 was ordered on 12 June 1943 but never laid down, let alone completed and sailed.
