itative ▁edge ▁with ▁the ▁world ' s ▁most ▁modern ▁ships . ▁The ▁F ub uki ▁class ▁had ▁performance ▁that ▁was ▁a ▁quantum ▁le ap ▁over ▁previous ▁destroy er ▁designs , ▁so ▁much ▁so ▁that ▁they ▁were ▁designated ▁. ▁The ▁large ▁size , ▁powerful ▁engines , ▁high ▁speed , ▁large ▁radius ▁of ▁action ▁and ▁un pre ced ented ▁arm ament ▁gave ▁these ▁destroy ers ▁the ▁fire power ▁similar ▁to ▁many ▁light ▁cru is ers ▁in ▁other ▁nav ies . ▁O bor o , ▁built ▁at ▁the ▁S ase bo ▁Naval ▁Ar sen al ▁was ▁the ▁sevent h ▁in ▁an ▁improved ▁series , ▁which ▁incorpor ated ▁a ▁modified ▁gun ▁tur ret ▁which ▁could ▁elev ate ▁her ▁main ▁battery ▁of ▁Type ▁ 3 ▁ 1 2 7 ▁mm ▁ 5 0 ▁cal iber ▁naval ▁guns ▁to ▁ 7 5 ° ▁as ▁opposed ▁to ▁the ▁original ▁ 4 0 ° , ▁thus ▁perm itting ▁the ▁guns ▁to ▁be ▁used ▁as ▁dual ▁purpose ▁guns ▁against ▁aircraft . ▁O bor o ▁was ▁laid ▁down ▁on ▁ 2 9 ▁November ▁ 1 9 3 0 , ▁launched ▁on ▁ 8 ▁November ▁ 1 9 3 0 ▁and ▁commission ed ▁on ▁ 3 1 ▁October ▁ 1 9 3 1 . ▁Origin ally ▁assigned ▁h ull ▁design ation ▁“ Dest roy er ▁No . ▁ 5 1 ”, ▁she ▁was ▁commission ed ▁as ▁O bor o . ▁ ▁The ▁ 4 th ▁Fle et ▁Inc ident ▁occurred ▁only ▁a ▁year ▁after ▁her ▁commission ing , ▁and ▁O bor o ▁was ▁quickly