in ▁mount s . ▁This ▁was ▁submitted ▁to ▁the ▁War ▁Department , ▁which ▁decided ▁to ▁change ▁the ▁ ▁guns ▁to ▁ ▁guns ▁mounted ▁in ▁tw in ▁arm ored ▁tur rets . ▁▁ ▁The ▁forward ▁tur ret , ▁with ▁a ▁traverse ▁of ▁ 2 3 0 ° , ▁was ▁mounted ▁on ▁the ▁forward ▁portion ▁of ▁the ▁upper ▁deck , ▁which ▁was ▁ ▁below ▁the ▁top ▁deck ; ▁the ▁rear ▁tur ret , ▁with ▁a ▁full ▁ 3 6 0 ° ▁traverse , ▁was ▁mounted ▁on ▁the ▁top ▁deck . ▁The ▁guns ▁of ▁both ▁tur rets ▁were ▁capable ▁of ▁ 1 5 ° ▁elev ation , ▁giving ▁them ▁a ▁range ▁of ▁. ▁Second ary ▁arm ament ▁was ▁provided ▁by ▁two ▁pairs ▁of ▁ ▁guns ▁mounted ▁in ▁arm ored ▁cas em ates ▁on ▁either ▁side ▁of ▁the ▁main ▁structure . ▁ ▁There ▁were ▁two ▁ ▁mobile ▁AA ▁guns ▁on ▁" sp ider " ▁mount s ▁for ▁anti - air craft ▁defense , ▁probably ▁the ▁ 3 - inch ▁Gun ▁M 1 9 1 8 ▁and ▁probably ▁added ▁circa ▁ 1 9 1 8 . ▁ ▁Over head ▁protection ▁of ▁the ▁fort ▁was ▁provided ▁by ▁a ▁ ▁thick ▁steel - re in for ced ▁concrete ▁deck . ▁ ▁Its ▁exterior ▁walls ▁r anged ▁between ▁approximately ▁ ▁thick , ▁making ▁it ▁virt ually ▁im pre gn able ▁to ▁enemy ▁naval ▁attack . ▁ ▁Const ruction ▁ ▁Const ruction ▁began ▁in ▁April ▁ 1 9 0 9 ▁and ▁last ed ▁for ▁five ▁years . ▁The ▁rock y ▁island ▁was