Roosevelt ... the target of a hapless U.S. Navy ship

Security might have been tight when U.S. President Franklin Roosevelt traveled secretly across the Atlantic on an American battleship as the first part of a journey to meet with Britain’s Winston Churchill and Russia’s Joseph Stalin in Tehran, Iran for a discussion of the war in late 1943 – but that mattered little when another American warship providing “protection” sent a live torpedo toward the ship carrying Roosevelt.

The story, relayed through a few newspaper accounts and a 1994 article by naval historian Kit Bonner in The Retired Officer Magazine, reproduced on the USS Iowa Veteran's Association website, goes something like this: Roosevelt was aboard the USS Iowa, which was accompanied by three smaller warships for the voyage in November 1943. After the convoy passed Bermuda, weather balloons were launched from the Iowa for a demonstration of the big ship’s anti-aircraft guns. Some of the balloons drifted into the area of the destroyer USS William D. Porter, one of the escort ships. The Porter’s captain – Lt. Commander Wilfred Walter – sent his crew to battle stations to join in the anti-aircraft gun show for Roosevelt. Walter also decided, although it’s not clear from published accounts if this was a planned part of the demo or not, to simulate a torpedo attack against the Iowa.

The torpedoes were supposed to be disarmed before firing, but one was not – and it quickly made its way toward the Iowa and Roosevelt, much to the horror of Walter and his officers and crew. After a few frantic attempts to contact the Iowa through signaling, the Porter broke the radio silence that had been in force for the voyage and informed the Iowa of the mistake. The Iowa turned in time to avoid the torpedo, which exploded behind the ship, after hitting its wake.
 
Fearing an assassination attempt on Roosevelt, the Iowa trained its guns on the Porter, but backed down after Walter told of the mistake. But Walter and his entire crew were ordered back to Bermuda with their ship. Ultimately, a crewman was found guilty in a court martial and sentenced to 14 years of hard labor for his mistake and attempt to destroy evidence, but Roosevelt overrode that punishment. Walter and at least some of his officers reportedly found themselves in dead-end Navy positions after the incident, too.

Unfortunately, the Porter seemed to be jinxed, finding itself on the wrong end of this and other mishaps throughout the war, as Bonner noted in the article referenced above. The ship met its end in an unusual way, too, in June 1945. A Japanese kamikaze, or suicide, plane carrying a large bomb failed to hit the Porter, but crashed alongside, without its payload exploding on impact. The plane slowly sunk under the water, where its huge bomb finally exploded, ripping apart the Porter’s hull under its waterline. The ship sank within hours.