SEMT Pielstick
The submarine displaced surfaced and submerged. It measured long, had a beam of and a draft of . For surface running, the boat was powered by two SEMT Pielstick diesel engines, each driving a single propeller shaft. When submerged each propeller was driven by a electric motor. "Spear" could reach on the surface and underwater. While snorkelling, the boat had a range of at . It was armed with a dozen torpedo tubes, eight in the bow and four in the stern. "Spear" had a complement of 6 officers and 41 ratings.