In what year did the submarine that sank the Tsushima Maru open to public tours?
Tsushima Maru: Tsushima Maru (対馬丸) was a Japanese passenger/cargo ship that was sunk by the submarine USS "Bowfin" during World War II, while carrying hundreds of schoolchildren from Okinawa to Kagoshima. USS Bowfin (SS-287):  Since 1981, she has been open to public tours at the USS "Bowfin" Submarine Museum and Park in Pearl Harbor, Hawaii, next to the USS Arizona Memorial Visitor Center.
1981