U-Boat is a fleet of submarines that can move inside living things or Stands and fire missiles.
U-Boat manifests as a colony of over one hundred miniature German military submarines, particularly from the First and Second World Wars. Unlike most submarines with rounded bows, U-Boat has pointed bows, resembling a boat more than a submarine.
The size of U-Boat can be adjusted by having the individual submarines combine.
Inside the Stand is everything a real submarine would have, such as various instruments and pipes. There are engineering sections, living quarters including beds and a kitchen, control rooms with monitors, missile storage, and a plumbing system. Narancia had never been inside his Stand previously and was amazed at how real it was.
U-Boat is capable of diving into the bodies of any living tissue or other Stands. The Stand could move freely through the host body, including human blood, teeth, skin, and other bodily fluids. If the host body or any of their bodily fluids such as the splatter of their blood touches another living thing, U-Boat could transfer to the new body.
It can go inside its user as well, protecting them from attacks. Bullets or projectiles that are fired would get caught on the side of the ship before hitting its user.
It is also capable of flying in the sky.
Torpedoes and Missiles
The Stand can fire and launch several torpedoes and exploding cruise missiles. If real missiles were shot from outer space, they would realistically burn up on reentry just like meteors, but U-Boat's missiles ignore physics and can travel through Earth at almost exactly the same speed as they were traveling in space.
U-Boat can also fire torpedoes and missiles while it is diving within a living being's body, dealing immense pain to the target when the projectiles burst through the host's skin.
Its user can regroup U-Boat to alter its size by having the submarines combine. A full-power U-Boat with nearly all of them combined creates a giant life-sized submarine that is at least a hundred meters long. Its torpedoes and missiles also resize into larger versions. If the Stand is enlarged to a sufficient size, its user and others are able to enter the vehicle. Jorge compares its full size to be as large as a building lying on its side.
U-Boat allows its user to use the various utilities of a submarine, including the following:
- A periscope headset the user wears over their right eye, appearing similar to the carbon dioxide radar headset that the original universe Narancia with Aerosmith has. The periscope allows the user to see farther and lock on to targets. U-Boat can be sent out to scout and the image of whatever it sees will be transmitted onto the periscope.
- A sonar system that can ping the host body that U-Boat is inside or amplify sound from far.
- A radio that can be used to communicate. Jorge uses it to contact Narancia while they are far from each other in their own separate U-Boats.
After Narancia places U-Boat inside Kars and Jorge explains to him what Stands are, Kars spontaneously creates his own enhanced copy of the Stand, tentatively named U-Boat Ultimate (
U-Boat Ultimate has a different design than Narancia's regular version. Compared to the original, it appears more futuristic and has a rounded bow like most normal submarine designs. Its surface does not seem to have any antennae or torpedo tubes. The sail is also shorter and flat on the top. Attached to the front on each side are jet engines and on its sides are larger diving planes.
The Stand's most notable feature is the submarine's external hull on its front which stretches outward and resembles the shape of a flower. In its center are several portholes arranged in a circle.
Although U-Boat Ultimate's abilities are theoretically enhanced compared to the original version, the only ability of it that Kars uses is its sonar system when he first tests out the Stand.
Kars uses the Stand's sonar to generate an extremely loud explosive noise, echoing through its target's body. It is impossible to block out the noise when the Stand is inside its target's body since blocking their ears would not help them when the noise comes from inside them. This ability causes Enrico Pucci to writhe on the ground in pain and Jorge Joestar's ears continue ringing even after the ability is turned off.
- The film Das Boot was localized in Japan with the title U-Boat (Ｕボート Yū Bōto). The fan-made English translation of the novel only refers to the Stand as Das Boot. However, Das Boot is not mentioned in the original novel or JOJOVELLER unlike other Stands such as Stepmom and The Iron Ladies which have both the Japanese names and foreign names in parentheses.
- As Kars gave Jorge a degraded copy of his U-Boat Ultimate, Jorge's U-Boat has the same design as U-Boat Ultimate but with the capabilities of Narancia's.