The submarine "K-420" was converted to test the "Meteorite" (SS-N-24) cruise missiles. The re-equipped submarine received the designation 667M (Yankee SSGN or Yankee Sidecar). The length and the width of the SSBN were increased up to 153 m and 15-16 m respectively. Outside of the pressure hull 12 launchers for the SS-N-24 missiles were located. The re-equipment began in December 1982 and the first launches of a cruise missile was conducted in December 1983.
From 1982 to 1991 some Yankee I SSBNs were equipped with 20 up to 40 launchers of SS-N-21 “Grenade”. They were designated as 667AT (Yankee Notch). Unlike the "K-420" that was converted to carry the SS-N-24 missiles, the shape of the deck behind the cabin was not altered. The displacement of the submarine was increased up to 11,500 tons and the body was lengthened to 140 meters.
Between 1988 and 1994 most converted Yankee submarines were removed from operational status. Some reports suggest that K-395 [a Yankee Notch] may remain in service.
|Soviet Designation||667AT Navaga|
|Design Bureau||Central Design Bureau for Marine Engineering "Rubin"|
|Chief designer||S.H. Kovalev|
|Builders||Severodvinsk, 'Komsomol Na Amur|
|Construction and Outfit||1982-1991|
|Number of ships||6|
|Armament||20-40 SS-N-21 "Grenade" missiles|
|4-533mm torpedo tubes|
|2-400mm torpedo tubes|
|Power Plant||2 pressurized water reactors |
2 steam turbines, 52.000 hp each
|Displacement||9.250 tons Surfaced |
11,500 tons Submerged
|Maximum depth||400 meters|
|Speed||12 knots Surface |
25 knots Submerged