The boat harbor (also known as the old boat harbor) in Kiel is a 4,200 square meter triangular body of water, south of the old town and west of the Schwedenkai and the Kiel Fjord.

The boat harbor is - together with the two bodies of water known as the Kleiner Kiel - a remnant of the original arm of the sea branching off from the Kiel Fjord, which enclosed the old town of Kiel, which was then on a peninsula, in the south and west. In the 19th century, the boat harbor was separated from what is now known as the Kleiner Kiel and the Kiel Fjord and has only been connected to them by pipes ever since
Quelle: Wikipedia