Here There Be Monsters Here There Be Monsters is a side quest in " Fallout 4 " . Detailed walkthrough . Here There Be Monsters is a side quest triggered by speaking with Donny Kowalski , who ' s located on the docks behind the Shamrock Taphouse . He ' ll excitedly tell the Sole Survivor he has been seeing an eye stalk peeking out of the water off the docks and will remain convinced it belongs to a sea monster , regardless of how the player character may respond . Through this dialogue , the quest will begin and the Yangtze submarine will be placed on the map , located directly in front of the pier Donny is standing on . It ' ll take a short swim to reach and is easily visible as a periscope covered in seaweed juts out of the water and often moves up and down . Alternatively , the quest can be started by simply swimming to the Yangtze . Once in the submarine , speak to Captain Zao , located in the first main room . He questions why the Sole Survivor is there , remarking that the war is long over and tells them that he has no treasure on board to plunder . He will go on to explain how his submarine ended up as it is and express surprise that he ' s been there for over 200 years already . He will then tell the Survivor his ship is no longer seaworthy and will ask if they ' ll help him fix it . Once the player character agrees to help , he advises that a dampening coil has been damaged and that he needs a new one , of which his war time intelligence told him could be found in Saugus Ironworks . At this point , he can be pushed into three different rewards with speech checks of increasing difficulty . He ' ll start by offering pre - War money , stating it must still have some value . He will offer caps if pushed further and if the final speech check is passed , he will reluctantly offer his sword as a final reward . If Out of the Fire has already been completed , the dampening coil may already be in the player character ' s possession . If so , there will be a speech option to simply hand it over . If the dampening coil does need to be acquired , travel to Saugus Ironworks , which is located directly south of the Slog and is occupied by the Forged , who populate and defend the inside and outside of the building . Several members of the Forged are very likely to be wielding flamers and will use Molotov cocktails frequently . If this location has already been explored before , it ' s entirely possible for it to already be cleared out . The dampening coil is located within the Saugus blast furnace , inside of the building . To reach this room , one must traverse the ground floor to the upper most floor , cross the middle of the room to the other half of the building , and then climb back down again . The blast furnace is found near the front of the second half of the building right in front of the door leading to the roof of the complex . The blast furnace is inhabited by Slag , the leader of the Forged , and entering the room will initiate dialogue with him . It may be possible to retrieve the dampening coil without killing him and the others inside , but they will attack the player character at the end of the dialogue regardless . Once Slag is defeated and the others in the room dealt with , the dampening coil can be found in the back right part of the room . Take it and travel back to the Yangtze . Upon returning , enter the submarine and speak with Zao again . He ' ll be ecstatic at the Sole Survivor ' s retrieval of the coil and go on to say he now needs nuclear fuel . He will say that during the Great War , one of the missiles on his submarine did not fire and that this is what he will need the player character to find in the depths of his ship , warning them that his crew is still alive in the deeper parts of the vessel and that they were not as fortunate as he was , as all have been turned into feral ghouls . Walk through the door leading to the bulkhead . Upon entering , several feral ghouls will be found roaming about . With the submarine rooms being so small , they ' ll need to be confronted as one travels further into the vessel . While there are many rooms , there ' s only ever one way to progress . Through this portion of the submarine , radiation levels can increase greatly at a consistent rate of 1 to 3 rads per second in the first room of the bulkhead and upwards of over 20 rads per second in the middle of the room where the warhead is found . Eventually , the final room will be reached where the first mate , who has been transformed into a glowing one , is found . This is the room the warhead is found in , which can be taken once the first mate is defeated . From here , Zao will need to be spoken to once again . He will give instructions to insert the dampening coil into the submarine followed by the warhead . If this is done in the reverse order , the submarine will explode , ending the quest and the Sole Survivor ' s life . Once this is done correctly , speak to Zao one final time . He will reward the player character with three homing beacon s , each of which allows for one tactical nuclear strike , ending the quest . If any or all of the speech checks were passed at the beginning of the quest , he will also give them 4 pre - War money for the first passed speech check , 200 caps for the second passed speech check , and his unique sword , Zao ' s sword , as the result of passing all three . Behind the scenes . The name of the quest is a reference to how cartographers historically drew sea monsters on unexplored areas of a map . In many cases , a phrase similar to " here there be monsters , " such as the Roman " here are lions " ( " hic sunt leones " ) , was written on maps as well .