Yangtze

The Yangtze-31 (Chinese: 扬子-三十一) is a Yangtze-class Chinese nuclear-powered ballistic missile submarine commanded by Captain Zao. When first discovered by the Sole Survivor in 2287, she is lodged in the shallow waters off the coast of the Commonwealth south of Boston Airport and northeast of the Four Leaf fishpacking plant. The submarine is not marked on the map until the Sole Survivor swims out to her. Upon discovery, the quest Here There Be Monsters will automatically be started if it hasn't been received already from Donny Kowalski near the Shamrock Taphouse.

Background
Sometime before the Great War, the Yangtze-31 was sent on patrol along the U.S. Atlantic coast with a payload of six strategic nuclear SLBMs and an unknown number of tactical nuclear missiles and torpedoes. When the Great War began, the Yangtze 's captain obeyed his orders to fire the submarine's strategic nuclear weapons at their targets. All but one of the missiles were successfully launched.

Shortly after firing its strategic missiles, the Yangtze-31 struck a mine that severely damaged her reactor and forced her to seek shelter in the Boston Harbor. The damage caused a reactor leak that immobilized the sub and ultimately killed or ghoulified the crew of around approximately two dozen men, of which only Zao retained his sanity.

Layout
The Yangtze is a unique design for a ballistic missile submarine. She has three large propellers located on either side and under the reactor control room, as well as a smaller propeller at the rear of the sub with the rudder. The sub's design is unique, as all of the facilities and machinery are located fore of the conning tower, which sits halfway on the sub, with only a small propeller and the rudder being behind the conning tower.

The first room the Sole Survivor comes to when entering the submarine is the control room/bridge where Zao is located. Down the stairs is the reactor control room with a radio room on the port side (left when facing forward). There are two doors on either side of this room that go to a small room with a cage wall and a large machine behind which is presumably the propeller drive shaft.

Behind the reactor room and under the bridge is a room with the machinery and instrument panels. On the port side of the room is Captain Zao's quarters and on the starboard side is the officer's mess. Forward of the reactor control room is the upper reactor level and contains the reactor access hatch and a stairway, on the port side, leading to the lower level. The lower level contains reactor machinery and two doorways, at the rear, leading to the engine room for the lowest of the large propellers.

Past the reactor room on the upper floor is a small room that contains two decontamination showers and a locked door with a stairway to the lower deck. There is also a science lab on the port side of the room. Forward of that room (still on the upper level) is the sub's mess room, galley, and food storage (the room opposite the galley). Forward of the mess is the crew quarters, containing 80 beds (configured in 8 stacks of three and 14 stacks of four), the sub's lavatories, and a laundry room (port side), as well as the ships med-bay/infirmary (starboard side).

At the front of the quarters are two doorways that lead into each other at the front of the sub, then lead into a room on the lower deck that contains machinery with a workshop on the starboard side and a storage room on the port side. The next room contains a doorway on the starboard side leading to the sub's armory and a hallway at the end leading to the silo room. The silo room contains the six missile silos with three along each side. Each silo has an access hatch that allows the crew to access the SLBM inside. All are closed except the one with the missile that failed to launch. The next room is a small room before the reactor room which contains a locked door to the upper level. Unlike the only other Chinese submarine the player character can personally encounter in the series, SSN-37-1A, the Yangtze is in fact a full-scale combat vessel with extensive crew amenities and visible missile and torpedo tubes.

Notable loot

 * Submariner uniform and submariner hat - Worn by Captain Zao.
 * Two fusion cores - One inside an open footlocker in the crew quarters, another found in a box underwater near the generator on the lowest level when going down the steep stairs past a skeleton lying on a barrel.
 * Nuka-Cola Quantum - Next to the bunk of dead crew member holding a Nuka-Cola truck, in the crew quarters.
 * Chinese officer sword - Lying on a desk in the captain's quarters, a room underneath the bridge.
 * Submariner hat - Worn by the first mate, now a glowing one (room has higher radiation levels).
 * Warhead - Found in the same room as the first mate, by looting the capsule on a nearby wall.
 * Stealth Boy - In a locked supply closet controlled by a Master locked terminal.
 * Vault-Tec lunchbox - In the galley on the table in the southeast corner.
 * First mate's password - Found on the first mate.
 * Hazmat suit - In the missile warhead room in an openable locker by the south door.
 * Zao's sword - Only obtainable if all Speech checks are passed when asking for a larger reward.

Related quests

 * Here There Be Monsters: Living on the ocean shorefront is a boy named Donny Kowalski, who asks the Sole Survivor to help him determine what he has been seeing out in the water recently.

Companion comments

 * When at this location companions make comments, which are activated at three locations: the bridge, the engine room, and after placing the warhead in the reactor.

Appearances
The Yangtze appears only in Fallout 4.

Behind the scenes

 * The Yangtze-class is an unique, retrofuturistic shape not similar any real-world submarine, unlike the SSN-37-1A, which bears a very conventional (albeit small) design. Its shape would give it a very conspicuous sonar profile.
 * The Yangtze is the longest river in both Asia and China. However, in real life, the term Yangtze（扬子) is relatively unused in modern Chinese, apart from the river. Chinese speakers would likely use the much more popular term Changjiang（长江）, while westerners use Yangtze. In addition, Yangtze would also have been spelled Yangzi in modern pinyin, since Yangtze is the romanized spelling.