As the chapter starts, get out of the torpedo with your knife ready. Prepare to be crouched and stealth throughout most of this chapter to avoid Commanders from sounding the alarm. In fact, your Signal Detected monitor should come up almost right away. Carefully move forward and eliminate the two guards on the ground level. One of them will walk right past you, making for an easy kill. Then go up the stairs to the next level, careful not to let anyone spot you. Stealthily taking out the two guards and Commander in this area can be tricky, but memorize the timing and strike fast, and things should work out. Once they're taken care of, make your way to the door. There's a map on the right wall just as you step through. Take it and continue moving to the next door.
Shack Staff posted a new article, Wolfenstein: The New Order Walkthrough Guide Part 11 - From the U Boat to the Secret Vault.
Make your way through the Nazi U Boat, and learn how to lower the step to make your way up to the secret vault with our Wolfenstein: The New Order walkthrough guide.