The tanker infiltrated at the start of Metal Gear Solid 2: Sons of Liberty is the Discovery.
Solid Snake boards the vessel during a storm on the Hudson River to investigate reports of a new Metal Gear. This opening chapter introduces the game's stealth systems, including hiding in lockers, photographing equipment, and moving through a ship controlled by Russian forces.
The Discovery is later revealed to be transporting Metal Gear RAY. Snake's mission changes dramatically when the tanker is attacked and sunk, setting up the events that lead to the Big Shell chapter.
The ship is often confused with Arsenal Gear, the enormous mobile fortress connected to the Patriots' plan. Arsenal Gear is not the opening tanker; it becomes central much later. Philanthropy, meanwhile, is the anti-Metal Gear organization associated with Snake and Otacon.