 The model submarine Nautilus used in filming was originally built as  one of the "SEAVIEW" filming models (eight feet long) for the 1960  movie "Voyage to the Bottom of the Sea", also  created/written/directed/produced by Irwin Allen. Many Hollywood  prop collectors bemoan the conversion of the SEAVIEW for use in this  very short lived TV show. The model has probably been destroyed at  this point.