ˈɛs twˈɛnti wˈʌn kəmplˈiːɾᵻd ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti tˈuː, dˈæmɪdʒd ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti fˈaɪv, ɹᵻbˈɪlt æz ˈɛs twˈɛnti θɹˈiː ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti sˈɛvən, ðˈɛn lˈɔst ɐɡˈɛn ɪn nˈaɪntiːnhˈʌndɹɪd nˈaɪnti tˈuː ðə kɹˈæft wʌz blˈoʊn ˌʌp bɪkˈʌz ðə ɹˈʌʃən nˈeɪvi kʊd nˌɑːt ɐfˈoːɹd ðə pɹˈaɪs ˈæskt fɔːɹ ɪts ɹᵻtɹˈiːvəl baɪ sˈælvɪdʒ kˈʌmpəniz.
S-21 completed in 1972, damaged in 1975, rebuilt as S-23 in 1977, then lost again in 1992 (the craft was blown up because the Russian Navy could not afford the price asked for its retrieval by salvage companies).