We Dive at Dawn 1943

April 1942 finds Lieutenant Freddie Taylor, John Mills, at the helm of the submarine Sea Tiger as its crew, freshly back from an unsuccessful patrol, are granted a week’s leave, under the watch of Navigating Officer - Lt. Gordon, RN Jack Watling. The mood is tempered by personal strain: Leading Seaman Hobson, Eric Portman, heads home to try to save his marriage, while Torpedo Gunner’s Mate Corrigan, Niall MacGinnis, heads to London for his own wedding. When the recall comes early, Corrigan is relieved but soon regrets not finishing his marriage. The mission ahead is top secret: sink Nazi Germany’s new battleship, the Brandenburg, before she transits the Kiel Canal for sea trials in the Baltic Sea, and the order to sail is issued at once.

Across the North Sea, the crew of the Sea Tiger picks up three shot-down Luftwaffe pilots from a rescue buoy and successfully blocks their radio alert from reaching German forces. When the submarine enters a minefield, one airman panics and reveals that the Brandenburg is farther ahead than anticipated. The airman is attacked by a countryman and dies, and Taylor makes a desperate gamble to pursue the Brandenburg into the German-controlled Baltic Sea, risking everything for the chance to stop the enemy ship.

When the Brandenburg is spotted, Sea Tiger unleashes its torpedoes, but dives before the outcomes can be assessed as German destroyers drop depth charges. To mislead the pursuing forces, the crew expels oil and debris, including the airman’s body, creating the illusion that the Sea Tiger has sunk. The ruse succeeds, and the submarine escapes, but it now has too little oil to reach Britain. The Germans, convinced of the Sea Tiger’s destruction, broadcast the bad news to Britain via Lord Haw Haw.

Taylor decides on a bold plan: have the crew abandon ship on the Danish island of Haago (which is, in fact, the island of Bågø). Hobson, a former merchant seaman who speaks German and knows the port, persuades Taylor to let him go ashore to search for oil. He succeeds, and Sea Tiger slips into the harbor under cover of darkness, using Hobson’s knowledge of harbour depth. Aided by friendly Danish sailors, they refuel while Hobson and other crewmen hold off the German garrison. Pincher is killed, and Oxford and Lt. Johnson are wounded, but they manage to get back to the Sea Tiger and begin to depart the port. The tanker they refuel from is later struck by German shells and catches fire, but Taylor, unwilling to risk the ship any longer, pushes back toward open sea.

On the voyage home, the crew is met by an escorting trawler and learns that they have sunk the Brandenburg. The Sea Tiger returns to base and flies the Jolly Roger for the first time, a sombre but triumphant signal of their hard-won victory.