Submarine Thumber
The Submarine is an escape route in Monstrum. It can be found at the lowest level of the Lower Decks, in the bow of the ship.


Submarine (Items)

The items you'll need to repair the Submarine.

In order to repair the Submarine, the player will need to find the following items:

  • Fuse - A fuse is required to power the control panel, which is used to recharge the submarine and release it.
  • Sub Battery - The submarine is powered by a battery that must be charged.
  • Sub Headlight - The submarine's headlights are missing and must be reattached. Note that you only need one headlight.
  • Welding Kit - A panel on the submarine's left side has come loose and must be seared shut.


1. Use the welding kit on on the broken panel on the left side of the submarine. This will take approximately 6 seconds.
2. Use the sub headlight on the left slot on the front of the submarine.
3. Use the sub battery on the slot on the right side of the submarine.
4. Insert the fuse and turn the power on in the area.
5. Activate the recharging sequence by interacting with the left button on the control panel. The room doors will close and the recharging process will take 2 minutes. To keep the monster out of the submarine room during that time, you can use the diving cylinders cart to block the doors (or the vents, if The Hunter is the monster). Basically, you have to place the cart in front of the door that the monster is trying to break through, until the recharging process is complete. However, if you fail to block the doors and the monster successfully breaches into the room, keep in mind that during and after the recharging sequence you cannot let the monster near the control panel unless it is chasing you. If you do, it will destroy it permanently. Your journal will update when the process is complete, and the bay doors to the water below the submarine will open.
6. Interact with the right button on the control panel to release the submarine.
7. Interact with the submarine (nearly anywhere will do, but aim towards the top of it from the side for safe measure).


  • MAKE SURE THAT THE MONSTER IS NOT IN THE ROOM BEFORE YOU START THE COUNTDOWN! It is impossible to evade them while locked in this room, unless you use the moveable cart as a "traffic cone", which means cutting it very close in the chase.


  • Initiating the countdown sequence will immediately draw the monster to the bay. Just after pressing the button to start the process, go to the diving cylinders cart (you can find it near the stairs that lead to the submarine control panel) and see which door/vent the monster is trying to break through. After you saw it, push the cart and place it in front of that door/vent until the monster gives up and tries to break another one. Repeat this process until the countdown sequence is complete. This video will show you how to perform this procedure correctly.
  • Keep in mind that every monster has a different way to breach into the room: The Brute and The Fiend will try to break through the doors using muscle strenght (the Brute) or ethereal powers (the Fiend), while The Hunter will try to get inside using the three vents located in the room.
  • If you fail to keep the monster out and it breaches into the bay, the room doors will open. In this case, the best way to kite the monster around while the recharge sequence is in progress is to jump down from the ledge near the control station right before it gets too close to you, and go out the door on your left. Wait here for the monster to come down the stairs (they cannot jump down from the ledge), wait for it to almost catch you, then run a few feet down the hall, immediately take the first right, enter the "middle" door to the submarine room, then go up the stairs of the control station, returning to the ledge where you started. Repeat this process until the sequence is complete. Alternatively, you can try to kite the monster out of the sub bay and up the stairs to the Main Deck. You can even pull it to the helipad and use the steam vents there the same way you would if you were refueling the Helicopter.
  • Keep in mind that the submarine must be released before it can be used. This is important, because if you try to evade the monster after the sequence is over and hide, the monster will still go back to the control panel and destroy it.
  • If the submarine is not fully repaired yet and you know the monster is coming, run up to the elevated platform and stand behind one of the large grates. Monsters cannot see through grates, but you'll be able to see it coming up the stairs. If you are seen however, wait for the monster to reach the stairs, then jump down from the platform and rush through the door on your left.
  • Welding kits can also be used to break the sliding lock on the doors that you previously locked, and are not consumed when used on the broken panel. Consider keeping one with you if you have the space.

Ending Cutscene

Caution: Spoilers!



  • The submarine is considered the most difficult escape route because of the great focus required at the end to prevent the monster from permanently destroying the control station, and because it requires a fuse, a valuable item required to enter power-locked rooms, activate the lights in entire areas, and gain access to the Main Steam Control Valve down in the Engine Room. Note that there will only be up to 4 fuses in total (which includes the fuse in the starting room) throughout the ship in a single playthrough of Monstrum.
  • If the monster destroys the control panel after the submarine has already been released, your journal will be updated stating that you failed and that you must find another route to escape. However, in this case your journal is wrong, and the submarine is still a functional escape route.
  • The Fiend gets no glory shot in the cutscene of this escape route; all you see are the lights flickering, and then the hatch slams shut, followed by what sounds like the Fiend attempting in vain to stop the submersible with its powers.
  • Curiously, turning off the power to the Control Station after the countdown has begun has no affect on it. The overhead lights in the room will turn off, but the red warning lights will not. This also has no effect on the countdown sequence either.

Escape Routes
The Life RaftThe HelicopterThe Submarine