Una-class submarine

Una-class submarine (also known as Type 911) is a class of six midget submarines built for the Yugoslav Navy at the Brodogradilište specijalnih objekata during the 1980s. They were designed with the purpose of laying small minefields and transporting naval special forces, with or without their submersibles, inside enemy controlled waters.

During the Croatian War of Independence and the dissolution of SFR Yugoslavia, most of the vessels were relocated to Montenegro. One, P-914 Zeta, was captured in drydock by Croatian forces. It was later on modified and entered service with the Croatian Navy as CROATIAN SUBMARINE Velebit.