The Una-class submarine (also known as Type 911) was a class of six midget submarines built for the Yugoslav Navy at the Brodogradilište specijalnih objekata (English: Special objects shipyard) during the 1980s. They were designed with the purpose of laying small minefields and transporting naval special forces, with or without their submersibles, in shallow waters that were inaccessible for larger submarines. Due to their mission profile that called for a small design as well as the need to stay undetected, they lacked torpedo armament and a generator for battery recharging.