This WWII US Navy T shirt is a reproduction of an original WWII design. The shirt says United States Navy with a USN Anchor in the center.
After the attack on Pearl Harbor, the US Navy was in the war. Over the next 4 years, many historic battles were fought, including but not limited to the Battle of the Coral Sea, Battle of Midway, Guadalcanal Campaign, Battle of Leyte Gulf. The USN supported landings in the Pacific campaign and European landings. When the Japanese surrendered, the formal ceremony was held on the battleship Missouri. By the end of the war, the US Navy had over 1600 warships.
During WWII, athletic style t-shirts were available for purchase at the PX and were commonly used in training and athletic situations. PT shirts with a variety of different unit logos are well documented in many WWII photographs.