Given the task definition and input, reply with output. In this task, five ordered key facts are given. All the given facts are expressed in natural language. Your job is to generate a story 100 to 1000 words long, that includes all the facts given as input in their order of appearance while expanding upon them to produce a broader, yet coherent, narrative.

Fact1: Offered duty ashore MacClain is determined to avenge men, Fact2: MacClain is allocated new ship and while befriends Joyce Cartwright, Fact3: Donnacona comes upon grisly sight Setting out as escort to convoy heading for England, Fact4: ship In is separated from convoy ocean storm, Fact5: other lost ships had been separated from other escort ships
In 1943, Lieutenant Commander MacClain Randolph Scott has just lost his ship and most of his crewmen due to enemy action. While accompanying a convoy, he was attacked by a Uboat with a distinctive large Iron Cross painted on the conning tower. The Uboat surfaced and machinegunned many of the survivors. Offered duty ashore, MacClain is determined to avenge his men. He is allocated a new ship and while waiting for it to be built, befriends Joyce Cartwright Ella Raines, whose brother Dick, an officer, was killed under his command. MacClains new ship is christened as HMCS Donnacona, and soon a crew of 65, including officer Paul Cartwright James Brown, Joyces younger brother is assigned to the corvette. Setting out as an escort to a convoy heading for England, the Donnacona comes upon a grisly sight, a lifeboat filled with dead sailors, the result of a deadly Uboat attack. In an ocean storm, his ship is separated from the convoy, but 300 miles from the Irish coast, MacClain finds other lost ships that had also been separated from the other escort ships. The captain of one of the ships, the tanker Egyptian Star relays the information that he thinks a submarine has been trailing the ship. The small group of ships becomes the target of Luftwaffe bombers that are chased off by a British fighter launched from one of the escort ships. The submarines below are still the main concern and when the Egyptian Star is torpedoed and sunk, MacClain attacks, sinking a Uboat with depth charges. Another Uboat surfaces and in a running battle cripples the Donnacona. MacClain attempts to ram the submarine and when it begins to dive, Lt. Cartwright and seaman Stooky OMeara Barry Fitzgerald set off depth charges, sinking the Uboat. As it breaks up, MacClain recognizes it as the one which had machinegunned his men, killing his former crew. The corvette, along with six surviving merchant ships, limps to safely in Ireland, but before it sets anchor, MacClain is asked to sail the Donnacona past the other ships in the harbor, so that its crew may be saluted for their bravery.