submarine
In German, a submarine is called a U-Boot, which is short for Unterseeboot. This term is used to describe a vessel that can travel underwater, and is often used in military contexts. The word U-Boot is commonly associated with the German navy, especially during World War I and World War II.
The submarine dives into the dark depths of the ocean.
This sentence describes a scenario where a submarine (U-Boot in German) is diving into the deep, dark parts of an ocean.
I built a model of a submarine.
The speaker in this sentence is suggesting that they have built a scale model of a submarine (U-Boot). Often, such models are used for display or hobby purposes.
She works on a submarine.
This sentence expresses that the person being discussed performs her professional functions on a submarine (U-Boot). The job could be anything from science research to military duty.