Henrietta .45 Supermatic

A Henrietta .45 Supermatic was a type of firearm.

History
In January 1965, Carl snuck aboard Captain Blacker's yacht while he was sitting at his desk, and shot him 5 times, fatally wounding him so that he could search for the plans to a nuclear device. Shortly after Carl found the plans and, upon exiting the yacht, blew it up, sinking it to the ocean floor, Tidman, who had planned to rendezvous with Blacker, donned diving equipment so he could search the wreck. There, he found the shells from the weapon's ammunition, as well as the 5 gunshot wounds Blacker had sustained.

Lady Penelope Creighton-Ward, under the alias "Gayle Williams", then had Parker write into a local newspaper that fashion model Gayle Williams planned to track Carl's gang down, including information on what type of firearm was used, and how many wounds were sustained. Carl read about this in said newspaper aboard his yacht shortly thereafter, leading him to travel to a boathouse, don diving equipment, and swim down to his gang's submarine hideout to warn the other members of his gang, Ritter and another gang member, about the supposed fashion model's plans, leading them to decide to kidnap "Gayle Williams", and attempt to murder her by "blow[ing] [her] sky high" while she was aboard his yacht. As part of the kidnapping, Carl boarded the FAB 2 and threatened "Gayle Williams" with the gun, warning that it was loaded, that he wouldn't mind using it, and telling her that she'd be going for "a little boat ride". "Gayle" then calmly told him that she'd be with him in a moment, leading him to shoot the mirror she was sitting in front of, with her retorting that she hoped he wasn't superstitious, as it was "7 years bad luck". Upon getting Lady Penelope aboard his yacht, he continued to hold his gun towards her even whilst steering, and while explaining his plan to her. (TV: The Man from MI.5)