During her first major overhaul,
Daniel Boone was retrofitted with
Poseidon C-3 missiles and the associated Mark 88 firecontrol system, as had the rest of her
class, . Poseidon was replaced by
Trident C-4 missiles and on 6 September 1980,
Boone became the first
James Madison operational with the new missile.
Daniel Boone entered the Tenneco Shipyard at
Newport News, Virginia sometime in late 1985 or early 1986 for refit. During post-refit sea trials on 7 April 1987 she ran aground in the
James River at Newport News. This grounding occurred primarily because the OOD (Officer of the Deck), in an attempt to counteract tidal currents, lowered the SPM (Secondary Propulsion Motor) which was quickly and violently snapped off on a sandbar. The OOD then ordered the SPM retracted which, when retracted would have opened up an unpluggable 6" diameter hole in the hull. This potentially catastrophic mistake was countermanded by watchstanders on the scene in the Machinery space. In spite direct orders from the CONN and Maneuvering, the senior watchstander on the scene prevented the SPM from being retracted, preventing the submarine from sinking in the James River. This accident, however, significantly delayed her departure from the refit yards because they had to obtain another SPM and repair the hull penetration in Tenneco Shipyard's dry dock. No ballistic missiles were on board. ==Decommissioning and disposal==