Did some research and the USS Trout was in a lot better shape than I thought - she was retained at Key West until 2003 and was not only in fully usable shape but could still dive (300 feet or less depth) and was capable of bottoming
http://www.submarinesailor.com/Boats.../helptrout.htm
From the site - the speed numbers are under remote control FYI
The Trout was sold to the Shah of Iran. She was rebuilt in 1979-1980 and restored to near perfect condition. Restoration included $26 million in upgrades, new engines, three sets of batteries, and all systems totally reconditioned. Before the transfer could take place the Iranians seized American hostages and the vessel was seized by the US along with other Iranian assets. The vessel lay at Inactive Ships Facilities in the Philadelphia Shipyard while legal and diplomatic efforts ensued.
The USS Trout was sold at scrap value to the Program Executive Office for Undersea Warfare (PEO USW) in 1994 and moored at Newport, Rhode Island. The vessel was then acquired by the NAWCAD Key West Detachment as an underwater acoustic target for ASW research and development, operational testing and training requirements for the US Navy.
Based on ASW fleet input, NAWCAD felt there existed a need for an underwater acoustic target. The US Navy has had a difficult time obtaining required test and training time on realistic ASW acoustic targets.
It was thought the USS Trout II could provide necessary and timely services as a dedicated asset. It could allow unrestricted active search, with no standoff required. It can operate in less than 300 feet of water and is capable of bottoming. It will operate at one to three knots and will allow torpedo terminal homing algorithm testing.
With a crew she was capable of 16 knots and still had crew quarters and accommodations
From a 2003 appeal to try to save the sub
This boat is a virtual time capsule, with the majority of her systems not only intact, but operational. Even her batteries are brand-new (without electrolyte)
Thus the Navy would have access to a fully operational diesel boat - i.e. she isnt a fast attack but she is capable of diving, has fresh batteries and still had her torpedo tubes and she can fire the Mark 48 - the Trout was actually the primary firing ship for the evaluation of the Mark 48 when it was first introduced into the fleet
One possibility for her may be that she is part of the Sea Lord's forces - i.e. he dispatched a ship with fuel to man her and take her up to Jacksonville