Humphrey Bogart visited the set as he began to film The Left Hand of God (1955). Lauren Bacall later recalled that John Wayne was the first to send flowers after Bogart became ill with cancer in 1956, even though he hardly knew Bogart.

Lauren Bacall said of this film, "That was supposed to be [Robert Mitchum], but he got into some brouhaha--probably had a few too many. [William A. Wellman was great; Wild Bill, a fascinating man! Not a good movie, but I liked working with Duke [John Wayne]. We didn't agree politically, but we got along well and had a sort of chemistry."

In an interview Lauren Bacall said that she took the role because Robert Mitchum was to be the male lead. After John Wayne took the role following Mitchum's departure, she expected to clash with him since she was a left-wing Democrat and he was a right-wing conservative Republican. She said that he was warm and friendly and they did not discuss politics. She later starred with him again in his last movie The Shootist (1976).

Gossip columnist Hedda Hopper, who shared star/producer John Wayne's right-wing political views, tried to persuade him not to cast Lauren Bacall for this film, due to her politics being the complete opposite of theirs, but he hired her anyway.

Robert Mitchum was originally cast as Capt. Wilder. He was fired from the film after an altercation in which he shoved the film's transportation manager into San Francisco Bay. Director William A. Wellman complained to John Wayne--whose company, Batjac Productions, was producing the film--that Mitchum "was on dope, always walking about six inches off the ground." Wellman said either he or Mitchum had to go. Gregory Peck subsequently turned down the role because he found it offensive and Humphrey Bogart wanted a $500,000 salary, which would have put the film over budget. Without a major male star involved, Warner Bros. contacted Wayne, threatening to pull out of their distribution deal for the film unless he took the role himself. To keep his new production company afloat, Wayne agreed to replace Mitchum.

Continuity

Bacall tells Wayne that the map he had been making was burned in the kitchen because there was no time to hide it before the troops arrived. A short time later, Wayne is seen writing on the same map (note the human anatomy on the front side of it).

After the emergency paddle wheel repair job at the ship graveyard, the planks on the paddle are still the original weathered red-painted planks instead of the plain unpainted scrap wood planks that were put on it during the repair.

When the ferry is first brought into the village for the evacuation, there are two 'eyes' on the bow. Shortly after, Big Han brings a sign, in Chinese, with the new name of the ferry, the Chiku Shan. Later the name of the ferry is shown in English, not Chinese, on each side of the bow and the sign in Chinese appears and disappears from under the pilot house.

When Big Han and Captain Wilder are talking on the sampan, two men are throwing their knives at a crudely-drawn face on a wooden post near them. The post is shown in close-up when the knives are thrown and stick into it, and then from farther away when they are pulled out. In the farther away shots when the knives are pulled out, a solid tall thin shadow, likely of another post, covers much of the target post, but it is not there in the close-ups.

When Wilder says "Half the Red navy's out there ...", the position of the wheel and the placement of his hands on it changes between shots.



Factual errors

When the Captain orders "No smoke!", the crew men throw buckets of water into the burning boiler to put out the fire. This would initially cause large volumes of white smoke. In addition, when superheated metal is suddenly cooled, it causes the metal to crack. Once the boiler was reheated, as when they enter Hong Kong, the boiler would have very likely exploded.



Revealing mistakes

According to the map drawn by John Wayne, the course from Chiku Shan to Hong Kong is in a Southwesterly direction. However, the morning after the storm when he has Lauren Bacall take the wheel he tells her to steer a course of zero four five (045) which a compass reading of Northeast, the exact opposite of their direction of travel.

When Captain Wilder leans against the window, the wall moves.

When the ferry pulls into Hong Kong, they encounter a Royal Navy vessel with close-ups of the sailors. Ordinarily, British sailors wear a tally on their caps with the name of their ship printed on it. However, the sailors' tallies only have "HMS" on them and no ship's name.

In three scenes with Captain Wilder and Big Han are talking, the sampan is not moving. The trees reflected in the water behind the sampan are the give away.

Two scenes were definitely "low budget" and were obviously scale mockups that weren't believable: 1. When the wood goes through the paddle, this is obviously a 2x4 going through a small model. 2. As the paddleboat comes into Hong Kong, it is clearly models and a fake city.



Miscellaneous

The paddle steamer was designed for operating on rivers, with a flat bottom and just a few feet of freeboard. With the high waves seen during the storm and a main deck that was not watertight, it would have taken on a lot of water and sunk in minutes.



Audio/visual unsynchronized

When the ferry is coming into the fishing village, Capt. Wilder lets Big Han blow the ship's steam whistle. However, no steam is seen coming from the whistle that is attached to the smokestack.