ShipShirts&trade; Men's SSN 720 USS Pittsburgh 6,184 tons of Diplomacy Short Sleeve T-Shirt ShipShirts Diplomacy line proudly feature your favorite Navy ship on a high quality 100% Pre-Shrunk Cotton 6.0 Oz T-Shirt. ShipShirts The Gold Standard in Naval Clothing The perfect gift for sailors, veterans and naval ship enthusiasts from 9 to 90.