The USS Discovery KSNM-3* was a dummy oil tanker used to secretly transport the first Metal Gear RAY prototype for offshore testing. Besides this, it was also a training tanker. It was run by a computer, so it required relatively little manpower for it to be used.
In 2007, the Discovery was guarded by the United States Marines led by Commandant Scott Dolph. As the tanker passed down the Hudson River, Sergei Gurlukovich's mercenary army, along with Revolver Ocelot, staged a siege of the tanker. The Russian soldiers eliminated much of the light presence of the guarding Marines on the decks and effectively had the ship under their control, save for the holds where the majority of the Marines as well as Dolph were stationed. The Marines had no idea their ship was under siege during this time.
At the same time, Solid Snake infiltrated the tanker, intent on capturing photographic evidence of Metal Gear RAY's existence. They deduced that it was the ship because the waterline around the ship was too high, as the navigational plans indicated that it should have discharged its cargo upriver. Shortly after infiltrating the ship, Snake witnessed the ship being taken over by Russian mercenaries, with the former crew also being killed by their knives. Snake fought Sergei's daughter, Olga. Now because of the introduction of a Cypher UAV, Snake and Dr. Emmerich (Otacon) learned that not only the Marines and the Russians were after the new Metal Gear, the Army was involved also. Despite the mercenaries having superior numbers and firepower, Snake managed to get to the holds where the Marines were in massive numbers.
Snake infiltrated the holds until the last hold where Metal Gear RAY was being held. After sending the photos of RAY to Otacon, the Gurlukovich Mercenaries led by Sergei and Ocelot came, holding the Marines hostage in the third hold. However, Ocelot betrayed Sergei and killed both the former and Dolph, as well as activating the Semtex bombs planted in the ship. When Snake rushed to Ocelot, Liquid Snake possessed Ocelot then commandeered RAY and devastated the hangar. The remaining Marines fought back while others desperately tried to escape. The ones that fought were easily wiped out as their weapons had no effect and several who tried escaping were either killed in the explosions or drowned.
RAY smashed the tanker in half before diving into the water, leaving the wreck of the Discovery floating on the river. At the time Ocelot was the only one identified to have survived. More than half of the tanker's crew, by this time, had gone down with the ship.
Following the sinking of the Discovery, the Big Shell offshore decontamination facility was constructed at the site to supposedly clean up after the wreck. Snake and Otacon's actions were also labeled as environmental terrorism (and marked as history's worst ever) by the Patriots-run media. Both kept quiet and underground until the Big Shell Incident began.
164 U.S. Marines (plus a crew of about 20).
Rooms and functions
The mess hall for the USS Discovery was noticeably small, namely due to the ship being mostly automated to the extent that the ship only needed a crew of approximately 20 live personnel. It also contained a food pantry, containing cardboard boxed foodstuffs.
The bridge itself contained precision equipment necessary for the monitoring and usage of navigational, engine control, communications, and all other major operational functions of the tanker. It was also auto-piloted by a Global Positioning Satellite system.
The crew lounge was the area that the crew could relax when they were off-shift. During the Tanker Incident, the TV broadcasted Dolph's speech about Metal Gear RAY.
Due to the USS Discovery's role as a dummy tanker, the drive section of the ship was located in the aft area, in order to include more oil tanks. Consequently, it also had a shortened propeller axle, and because of the simplistic design of the drive section, a greater emphasis was placed on hull strength.
The lifeboats on board the Discovery were fully-enclosed and fire-resistant models that were also equipped with their own oxygen pumps. In addition, they had a water-based cooling system and a self-contained air supply on board in the event that the boats were sealed, there would still be air available for the crew as well as the engine's operation. They could also automatically right themselves if they overturned, and could withstand contact with fires for a significant period of time. A major drawback, however, is that they were slow.
Deck-A ~ Crew's Quarters
Behind the scenes
In Hideo Kojima's original game plan for Metal Gear Solid 2: Sons of Liberty, the events on board the USS Discovery were originally to have taken place on an aircraft carrier, and was also given the secret name of "Arsenal Ship." Also, one of the reasons for the Big Blue Apple's creation was to recover the sunken Arsenal Ship, namely for valuable data regarding the Arsenal Gear project.
The flag on board the Discovery has the Cyrillic letter Ef (ф).
If the player tries to open a door that doesn't lead to another area of the map, a short cutscene will play where Snake will attempt to turn the wheel on the door only for it to come off, causing him to react in shock, and then gently put it back on.
The name of the Discovery's on-board computer, the Monorith, is a reference to the Monolith from 2001: A Space Odyssey (the name is misspelled due to an incorrect transliteration from Japanese). The ship being named "Discovery" is also a reference to the film.
The setting on board the Discovery was later reused for the non-canon Snake Tales story, "Confidential Legacy." Here, the Discovery is a Marine tanker that is transporting a Metal Gear, rediscovered in Eldera, back to America, but is later taken over by Sergei Gurlukovich's troops.
The tanker was indirectly referenced in the Marines card description in the non-canon game Metal Gear Acid, where it was identified as a "secret training tanker." The same source also stated that the casualties on the Marines' end in the ending of the Tanker Chapter was "more than half."