Question: The Nacken-class submarines also known as the A14 type were built for the Swedish Navy in the late 1970s. The boats were authorised in 1972 and the programme was completed in 1981. All boats were built by Kockums in Karlskrona. The boats had a teardrop hull and diving depth was 150m. Between 1987 and 1988 the Nacken was converted to Air Independent Propulsion (AIP) using a closed cycle Stirling engine. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Answer:
Mean Of Transportation