Vishnya-class intelligence ship
The Vishnya class, Soviet designation Project 864, are a group of intelligence collection ships built for the Soviet Navy in the 1980s. The ships continue in service with the Russian Navy. The Russian Navy operates seven of these ships.
SSV-535 Kareliya (foreground) and USS Texas in 1988
SSV-208 Kurily in 2005
A spy ship or reconnaissance vessel is a dedicated ship intended to gather intelligence, usually by means of sophisticated electronic eavesdropping. In a wider sense, any ship intended to gather information could be considered a spy ship.
USS Liberty, a "technical research ship", in 1967
Oker, an Oste-class ELINT and reconnaissance ship, of the German Navy
While USNS Vanguard was not strictly a spy ship, being used for space tracking, there is some overlap between her capabilities and those of a spy ship.