The working title of this film was Corvettes in Action. The film opens with the following written foreword: "This is the story of a Corvette, a little ship, a fighting ship, and of the officers and men of the Royal Canadian Navy, who have made the name Corvette a byword for endurance and sacrifice among the submarine lanes of the North Atlantic...Without the active cooperation of the men and ships of the Royal Canadian Navy this story could not have been told..." The film ends with the following written epilogue: "She will carry on, and those who come after her, for her name is legion, and the legend of her and of those who fight in her is an inspiration for all men who believe in courage and hope."
       According to HR, producer-director Howard Hawks signed a one-picture contract with Universal in Jun 1942. Hawks selected Corvette K-225 as his contract picture, and Robert Rosson as the film's director. Screenwriter Lt. John Rhodes Sturdy, the commanding officer of one of the Canadian corvettes, was also assigned to the film for five weeks as a technical advisor. According to MPHPD, Sturdy, a former Chicago and Montreal newspaper reporter, was loaned to Hawks by Canadian Navy Intelligence. On 11 Jun 1942, HR reported that Rosson was going to be the second unit director on the film, shooting ten days on location in the Atlantic with a convoy, and Hawks was going to direct, as well as produce.
       On 27 Jun 1942, actors Robert Stack, Dick Foran and Patric Knowles were announced as cast members, but none appeared in the released film. On 30 Jun 1942, HR reported that Hawks was so impressed with the Universal 1942 film Eagle Squadron (See Entry), that he wanted to use many of the cast members of that film, including Stack, Diana Barrymore, Evelyn Ankers, Leif Erikson , Jon Hall and Nigel Bruce, and that he was willing to change the shooting schedule of Corvettes K-225 to accomplish this. However, none of those actors appeared in the released film.
       On 2 Jul 1942, Hawks sent a revised copy of the script to Admiral Percy W. Nelles, the commander-in-chief of the Royal Canadian Navy, for his approval. According to HR, this revised script was co-written by Sturdy and Edward Chodorov. Sturdy, however, received sole screen credit for original screenplay, and it has not been determined if any of Chodorov's work was used in the released film. Once the script was approved by the admiral's office, Rosson and his crew were to shoot at one of the Canadian ports, then accompany a convoy to England. On 31 Jul 1942, HR announced that Rosson, along with business manager Vernon Keays, chief cameraman Harry Perry, crew members Len Powers, Bert Eason, Roland Smith and Harry Gudstram, as well as actors Robert James Hale , Rex Lease and Orville R. O'Connell were currently with a Canadian convoy, and that they would remain at sea for two to four weeks. While Lease is credited in SAB as appearing in the picture, it has not been confirmed if either Hale or O'Connell appeared in the released film.
       A 17 Dec 1942 HR news item stated that Rosson was finally ready to begin principal photography on Corvette K-225, having returned from shooting over 40,000 feet of footage while on location with the Canadian convoys. Later HR news items, however, raised the estimate of footage shot on location to 77,000 feet, adding that Rosson had accompanied five cross-Atlantic convoys over a three-month period. In mid-Jan 1943, it was announced that Harry Perry, who had been borrowed from Paramount, was being made director of photography on this film, based on his excellent work while on location with the convoys. In early Feb 1943, however, just prior to the commencement of principal photograpy, Perry was replaced as director of photography by Tony Gaudio, who was borrowed by Universal from Warner Bros. Gaudio received an Academy Award nomination for his cinematography on the film, but lost to Arthur Miller and his work on The Song of Bernadette (See Entry).
       Actress Ella Raines made her feature film debut in this film, after having been discovered by Hawks and his then-business partner, actor-producer Charles Boyer. According to HR, Universal purchased her contract from Hawks and Boyer, based on her performance in this film. HR also reported that actor James Brown was borrowed from Paramount for the film. According to HR news items and Universal press materials, the Canadian corvette The Kitchener, which was used extensively in the picture, had been cited three times for valor at the time of the film's release. Among other accomplishments, The Kitchener was responsible for the rescue of seventy-three merchant sailors, whose ship sank after striking a reef.
       While MPH gives Corvette K-225's national release date as 1 Oct 1943, HR news items state that the film's world premiere was held on 19 Oct 1943 at the Central Theatre in Ottawa, Canada, with the proceeds being donated to the Navy League of Canada. According to HR, singer Kate Smith hosted a coast-to-coast radio broadcast of the premiere, which was attended by Rosson and actor Randolph Scott, as well as Canadian Prime Minister Mackenzie King and Princess M. Juliana of the Netherlands. Three trans-Atlantic radio broadcasts were also held in conjunction with the premiere of the film, which coincided with the Fifth Canadian War Loan Drive.