Me and my dad took a trip with the torpedo boat T121 Spica this summer, the outing was coordinated with R142 Ystad.
These are ships from the cold war being run and maintained by volenteers and while they are not running them at full speed to save the engines and fuel, we did run at about 30 knots.
They only use GPS as a fallback navigation system, and mainly use radar and charts.
They also use period communications equipment, and try to be as authentic as possible.
During the trip passengers got full access to the ship, including the bridge, CIC, even the stern, but you needed ear defenders, the turbines was increadibly loud, I never went back there despite my excellent ear defenders.
