U-511 is a fictional anthropomorphized submarine character from Kantai Collection, based on the German submarine U-511. She is portrayed as a quiet, gentle, and somewhat reserved ship girl, often associated with a calm and innocent personality. In the series, she serves as a submarine unit in naval battles, contributing stealth and tactical support. U-511 is also notable in the franchise because she later becomes the basis for the character Ro-500 after transfer and transformation, linking her to a significant story element in the Kantai Collection universe.