Today, "Cod" is one of the finest restored submarines on display and is the only U.S. submarine that has not had stairways and doors cut into her pressure hull for public access. Visitors to the ship use the same vertical ladders and hatches that were used by her crew. She also has unique attractions such as the 5-inch deck gun that still can be rotated by visitors and mock-fired by "Cod"s volunteer crew. The "Cod" 's Mark IV Torpedo Data Computer is also fully restored, as well as other various parts on the submarine.