On 28 November 1943, President Franklin D. Roosevelt, Premier Joseph Stalin and Prime Minister Winston Churchill met for a series of talks at the Soviet Embassy in Tehran, Iran. The Tehran Conference was held to plan final strategy in the war against Hitler's Germany and its allies, and the primary discussion centered on opening a second front in Western Europe. The conference would last until 01 December.
Here is newsreel coverage of the conference...
Traveling to Tehran, President Roosevelt had no Air Force One, Boeing 747, to take him there. His first leg would be via sea. It was not a submarine, but a battleship, the USS Iowa which transported him to Casablanca, Morocco, on the first leg of his trip. Navy ships, even today, only have showers (hence Navy showers) for maintaining clean bodies. President Roosevelt being confined to a wheelchair due to polio, could not effectively use one. Therefore, the United States Navy installed a bathtub in the Commanding Officers inport stateroom for the President's use. USS Iowa is the only ship in the United States Navy that has a bathtub onboard.
While at sea on his way to Casablanca, President Roosevelt asked on 14 November to watch USS Iowa conduct an anti-aircraft drill. The drill began with the release of a number of balloons for use as targets. While most of these were shot by gunners aboard Iowa, a few of them drifted toward one of the Iowa's destroyer escorts USS William D. Porter, DD-579, which shot down balloons as well.
The Porter, along with the other escort ships, also demonstrated a torpedo drill by simulating a launch at Iowa. This drill suddenly went awry when the #3 torpedo aboard William D. Porter fired from its tube and headed toward Iowa. Iowa turned hard right (starboard) to avoid being hit by the torpedo. Roosevelt, meanwhile, had learned of the incoming torpedo threat and asked his Secret Service agents to move his wheelchair to the side of the battleship, so he could see. Shortly afterward, the torpedo exploded in the ship's wake about 3,000 yards astern of the Iowa. Iowa was not damaged, but her gun crews were ordered to train her main guns on William D. Porter out of concern for an assassination plot. The skipper of the Iowa radioed to the escorts, "What happened?!," and skipper of the Porter Lieutenant Commander Walter sheepishly replied, "We did it."
Following these events, the William D. Porter's captain, and her entire crew, were placed under arrest - the first time in U.S. Navy history that this had occurred. The ship and her crew were ordered to Bermuda for an inquiry into the Iowa affair. Lieutenant Commander Walter and several of his officers were sentenced to shore duty. Torpedoman Lawton Dawson, whose failure to remove the torpedo's primer had enabled it to fire at Iowa, was sentenced to hard labor, though President Roosevelt intervened in his case, as the incident had been an accident.
For the remainder of the war, the crew of the Porter would have to suffer the ribbing of other Navy ships, who on meeting would semaphore the message, "Don't shoot! We're Republicans!"