In his 2008 autobiography "My Word Is My Bond", Sir Roger Moore recalled that Lee Marvin got into a fight with Japanese journalists at an airport while making this movie. He said Marvin still hated the Japanese because of his war experiences.
Sir Roger Moore and Lee Marvin got into a fight during filming, which Moore won. Marvin recalled, "The guy is built like granite. Nobody will ever underestimate him again."
The story of this movie was inspired by one of the most spectacular and adventurous events that took place during World War I, in German East Africa, later Tanganyika, later Tanzania, in late 1914 to early 1915, known as the Battle of Rufiji Delta, in which the German light cruiser S.M.S. Königsberg was blockaded, and finally sunk by various British units.
Lee Marvin was less than four years older than Sir Roger Moore.