Alfred Hitchcock's original director's cameo was cut by order of the censors. He and his secretary played deaf-mute pedestrians. When Hitch's character made an apparently indecent proposal to her in sign language, she slapped his face. A more conventional cameo in front of a drugstore was substituted.
The shot of the ship on its side toward the end was an actual shot of the ocean liner SS Normandie, which had caught fire and capsized at its pier in New York. The fire was an accident, not sabotage (a cutting torch accidently set fire to some kapok life vests), though there were rumors of sabotage at the time.
Before he sold the property and the services of Alfred Hitchcock to Frank Lloyd Productions for $20,000, David O. Selznick had originally planned to film it himself with Gene Kelly, who had not as yet made a movie, in the leading role.
Alfred Hitchcock thought that Robert Cummings was "a competent performer" but found his performance, and the picture, suffered because Cummings "belongs to the light-comedy class of actors" and had "an amusing face, so that even when he's in desperate straits, his features don't convey any anguish." He thought Priscilla Lane "simply wasn't the right type for a Hitchcock picture."
Alfred Hitchcock wanted to be sure of a degree of authenticity for certain roles and was not averse to unconventional casting to achieve it. For instance, he pulled the company's best boy from the electrical crew to play the friend killed in the factory fire because Hitchcock thought he looked perfectly like a working man.
When the French liner the Normandie burned and partially sank in New York City harbor, Alfred Hitchcock quickly dispatched a Universal newsreel crew to the scene to get footage that he later incorporated into the film, intercut with studio shots of the saboteur smiling from the back seat of a taxi as he looks out on the supposedly sabotaged ship.
Alfred Hitchcock cut corners wherever he could. The mansion set was built onto a staircase left over from a Deanna Durbin musical; a back-lot storage building became the doomed aircraft plant. He also included a number of mattes and rear projections, the use of which has long been the subject of debate about the director (ingenious cinematic statement or obvious special effect?).
A couple of slightly different versions have been offered about how Alfred Hitchcock got the shot of Frye falling from the Statue of Liberty in Saboteur. One version claimed Norman Lloyd sat on a revolving, tottering chair, making appropriate movements; another says he was suspended on a wire. What is for certain is that he was shot against a black background while the camera swiftly pulled up and away from him, and the Statue and ground below were matted in later.
While being held in the library of Ms. Sutton, Kane was trying to signal Martin by highlighting a book title with his thumb. The books next to "ESCAPE" are: Method of Criminal Investigation, Coaster Captain, Sketch of a Sinner, The Rash Act, Conquerors of Time, and Bad Company. Coaster Captain actually foretold the next sabotage event, which was in the NYC harbor.
For the shots of police inspecting the long circus caravan at night, Alfred Hitchcock created perspective by using vehicles--and people--of different sizes, starting with full-sized trucks and extras at the closer end of the caravan, using smaller trucks and shorter people as it receded into the distance, and finally miniatures and cutouts with workable arms with tiny illuminations to simulate flashlights at the far end.
The only actor Alfred Hitchcock gave much direction to was Otto Kruger, who never pleased him as the head villain. Otherwise, he preferred to let the actors work out their roles in rehearsal and gave them direction mostly on timing in front of the camera. He believed he could solve any acting problem with camera work, such as filming Kruger's lengthy fascist soliloquy from a disconcerting distance.
For the factory sabotage, Alfred Hitchcock simply used a shot of the front of the building with black smoke slowly billowing into the frame. Robert Boyle said the director made a drawing "in which he drew just the big doors and then he did a big scribble. He said, 'There will be an explosion.' And I thought that scribble more illuminating than the finest drawing you could make."
According to Associate Art Director Robert Boyle, Alfred Hitchcock knew "almost any shot will not hold longer than five seconds and that a matte in particular is going to be on for no more than five seconds. Then the audience doesn't have time to find the problems."
Alfred Hitchcock was particularly distressed about not getting the villain he wanted. To convey the sense of these homegrown fascists being regular people, the ones you would least likely suspect, he wanted the very All-American former silent film actor and Western star Harry Carey. However, Carey's wife Olive Carey was very indignant about the suggestion. Hitchcock told François Truffaut she said, "I am shocked that you should dare to offer my husband a part like this. After all, since Will Rogers' death, the youth of America have looked up to my husband!"
To achieve the sensation of the people at the ship launch being thrown up in the air during the explosion on the dock, Alfred Hitchcock had the cameras pan quickly down each of the extras, from head to toe, and cut them together quickly.
Universal was concerned with the 50+ sets Alfred Hitchcock ordered, including a vast desert scene to be built on Stage 12 with a reconstruction of part of a river and waterfall, as well as the set for the Park Avenue mansion's grand ballroom.
Alfred Hitchcock tried to get John Halliday for the villain role. He was living in Hawaii, and travel restrictions imposed after Pearl Harbor made it difficult for him to be available in a timely fashion.
Tobin suggests as a book for Barry Kane, "Death Of A Nobody." It was meant as a portent of Barry Kane's future. There was such a book (released in 1911) authored by Jules Romains. It is an author's view of life and events, and not a murder mystery.
The trivia items below may give away important plot points.
Although the script was originally written with Germans in mind as the villains, still Alfred Hitchcock later decided not to mention "Germans" at all in the film. So the villains in the film became far more ambiguous.
The famous shot of Fry falling from the Statue of Liberty is an optical illusion: instead of falling away from the camera, Norman Lloyd is actually leaning back on a saddle, while the camera moves upward and away from him.
Alfred Hitchcock used the idea of "looks can be deceiving" throughout this entire film. Examples: 1) Fire extinguisher filled with gasoline; 2) Tobin playing with his granddaughter when he is first introduced; 3) "Blind" Man Philip Martin who is "totally aware" of everything that is going on; 4) Patricia Martin (Priscilla Lane) believing that Barry is a saboteur, because she believes he "looks" like a saboteur and he has a saboteur's disposition; 5) The "little" major in Circus Caravan who is a "big" trouble maker; 6) "Abandoned" Soda City; 7) Freeman (Clem Bevans) believing Barry based on what he saw and the "surface" information Barry provided to him; 8) Patricia Martin believing the Sheriff (Charles Halton and his words; 9) A party for charity affairs hosted by Mrs. Sutton (who secretly works with spies and saboteurs); 10) People ignoring Barry and his words (about Mrs. Sutton and others with her being spies and saboteurs) by saying that Barry is drunk and he is not even dressed; 11) Barry and Patricia Martin are "trapped" at a public place (Mrs. Sutton's big party); 12) Patricia Martin using "lipstick" to write the information about her; 13) The cop not taking Barry and his words seriously about the ship being sabotaged; 14) Frank Fry and the bomb detonator is inside a fake American newsreel truck. Another example is the use of "an old-fashioned peel telephone" in the visually "abandoned" office at Soda City. The message that comes through this telephone is what matters, not the physical appearance of the phone. Another interesting touch is Barry doesn't reveal anything about Patricia Martin to Freeman (Clem Bevans) in Soda City, but he later learns that Freeman knew far more than he did about Patricia Martin when they reach Mrs. Sutton's room.