They were replaced by conventional weapons  such as the Mk 54 Torpedo that provided ever-increasing accuracy and range as anti-submarine warfare technology improved.
ðeɪ wɜː ɹᵻplˈeɪst baɪ kənvˈɛnʃənəl wˈɛpənz sˈʌtʃ ɐz ðɪ ˌɛmkˈeɪ fˈɪfti fˈoːɹ toːɹpˈiːdoʊ ðæt pɹəvˈaɪdᵻd ˈɛvɚɹɪŋkɹˈiːsɪŋ ˈækjʊɹəsi ænd ɹˈeɪndʒ æz ˈæntaɪsˈʌbmɚɹˌiːn wˈɔːɹfɛɹ tɛknˈɑːlədʒi ɪmpɹˈuːvd.