At the time it went missing, Nanggala had 53 people on board, including 49 crew members, one commander and three weapons specialists.[35] The highest-ranking naval officer in the submarine was Colonel Harry Setyawan, the commander of the submarine unit of the 2nd Fleet Command. Subordinates with him were Lieutenant Colonel Heri Oktavian, the commander of the submarine, and Irfan Suri, an officer from the Weapons Materials and Electronics Service.[36]