▁passing ▁El ▁Fra ile , ▁where ▁three ▁ 1 2 0 ▁mm ▁guns ▁were ▁mounted : ▁one ▁H ont oria ▁ 1 2 ▁cm ▁gun ▁from ▁the ▁Spanish ▁cru iser ▁Antonio ▁de ▁Ul lo a , ▁and ▁two ▁shorter ▁ 1 2 0 ▁mm ▁guns ▁from ▁the ▁Spanish ▁gun bo at ▁General ▁Le zo . ▁▁ ▁The ▁shore ▁guns ▁ex changed ▁fire ▁with ▁, ▁which ▁was ▁briefly ▁ill umin ated ▁by ▁a ▁so ot ▁f lare - up ▁from ▁her ▁stack s , ▁and ▁soon ▁also ▁, ▁ ▁and ▁ ▁opened ▁fire . ▁However , ▁De we y ' s ▁ships ▁passed ▁the ▁for ts ▁without ▁significant ▁damage , ▁and ▁fought ▁the ▁Battle ▁of ▁Man ila ▁Bay ▁in ▁the ▁morning . ▁ ▁Pl anning ▁and ▁design ▁ ▁The ▁Board ▁of ▁Fort ifications ▁cha ired ▁by ▁William ▁H . ▁T aft ▁recommended ▁that ▁key ▁har b ors ▁of ▁territ ories ▁acquired ▁by ▁the ▁United ▁States ▁after ▁the ▁Spanish – American ▁War ▁be ▁fort ified . ▁Con sequently , ▁El ▁Fra ile ▁Island ▁was ▁fort ified ▁and ▁incorpor ated ▁into ▁the ▁ ▁har bor ▁def enses ▁of ▁Man ila ▁and ▁Sub ic ▁B ays . ▁ ▁Initial ly ▁Fort ▁Dr um ▁was ▁planned ▁as ▁a ▁mine ▁control ▁and ▁mine ▁cas em ate ▁station . ▁However , ▁due ▁to ▁in ade qu ate ▁def enses ▁in ▁the ▁area , ▁a ▁plan ▁was ▁de vised ▁to ▁level ▁the ▁island , ▁and ▁then ▁build ▁a ▁concrete ▁structure ▁on ▁top ▁of ▁it ▁armed ▁with ▁four ▁ ▁guns ▁in ▁tw