The submarine USS Dorado (SS-248), captained by Lieutenant Commander Earle C. Schneider, departed New London on October 6, 1943, for duty in the Pacific via the Panama Canal. After getting underway, she was never heard from again. She never made it into the canal zone, so whatever the event was that took her out occurred either in the Atlantic or the Caribbean Sea. A Court of Inquiry was unable to reach definite conclusions as to the cause of the Dorado’s loss. It adjudged the cause as unknown. The Commander-in-Chief, United States Fleet, listed three possible causes for her loss: operational casualties, enemy action, and attack by friendly forces. On the Atlantic side of the canal the “enemy action” would involve u-boats. We know the U-214 planted 15 mines near Colon, about three miles off the canal’s eastern entrance, on 8 October 1943. On October 13-14 she planted two EMS mines east of the Antilles. The EMS was a drifting mine. It floated on the surface and exploded on contact with a ship’s hull. It was armed 10 minutes after launching and was designed to stay afloat for 72 hours, after which it sank itself automatically. The Dorado was in the vicinity of all of these mines during the period when they posed the greatest hazard. The U-214 documented hearing a heavy explosion followed by a series of eight more just like it, on October 15, 1944, near the EMS planting. These multiple explosions could have been caused by the Dorado. She would be passing through that area en route to the Panama Canal. There is no record of any other vessels lost in that specific area on that date. None of the other u-boats in the area reported any attack on a submarine or were involved in planting mines. Could the answer to the Dorado mystery be the U-214 and its EMS mines? For now, only the 77 souls within her know the answer to that question. Hopefully someday the Dorado will be found and the condition of her hull will provide clues.