1 9 8 6 ▁for ▁a ▁third ▁over ha ul ▁after ▁comple ting ▁her ▁ 5 8 th ▁d eter rent ▁pat rol . ▁She ▁depart ed ▁Port sm outh ▁Naval ▁Sh ip yard ▁in ▁November ▁ 1 9 8 8 , ▁then ▁head ed ▁south ▁for ▁her ▁post - over ha ul ▁D AS O . ▁In ▁May ▁ 1 9 8 9 ▁she ▁began ▁her ▁final ▁series ▁of ▁P ose id on ▁strateg ic ▁d eter rent ▁pat rol s . ▁ ▁James ▁K . ▁Pol k ▁celebrated ▁her ▁ 2 5 th ▁year ▁of ▁commission ed ▁service ▁in ▁April ▁ 1 9 9 1 . ▁She ▁finished ▁her ▁ 6 6 th ▁and ▁final ▁strateg ic ▁d eter rent ▁pat rol ▁in ▁August ▁ 1 9 9 1 . ▁ ▁Con version ▁to ▁attack ▁sub marine ▁In ▁August ▁ 1 9 9 2 , ▁James ▁K . ▁Pol k ▁began ▁a ▁nin ete en - month ▁ship yard ▁conversion ▁that ▁removed ▁her ▁ball istic ▁miss iles ▁and ▁de activ ated ▁her ▁miss ile ▁tub es , ▁converted ▁her ▁into ▁an ▁attack ▁sub marine , ▁and ▁installed ▁D ry ▁De ck ▁Sh el ters ▁on ▁her ▁deck ▁which ▁would ▁allow ▁her ▁to ▁support ▁special ▁war fare ▁operations . ▁Upon ▁completion ▁of ▁this ▁conversion ▁in ▁March ▁ 1 9 9 4 , ▁her ▁h ull ▁classification ▁symbol ▁was ▁changed ▁from ▁S SBN - 6 4 5 ▁to ▁SS N - 6 4 5 ▁to ▁reflect ▁her ▁conversion ▁from ▁a ▁fleet ▁ball istic