0 - deg ree ▁angle ▁sides . ▁Within ▁this ▁thick - w alled ▁b unker ▁were ▁two ▁ ▁Bro oke ▁pivot ▁rif les , ▁one ▁forward , ▁the ▁other ▁a ft , ▁each ▁capable ▁of ▁firing ▁from ▁three ▁different ▁fixed ▁positions . ▁Both ▁can n ons ▁were ▁protected ▁on ▁all ▁sides ▁behind ▁six ▁exterior - mount ed , ▁heavy ▁iron ▁shut ters . ▁The ▁ram ▁was ▁prop elled ▁by ▁tw in ▁ 3 - bl aded ▁sc rew ▁prop ellers ▁power ed ▁by ▁two ▁steam ▁engines , ▁each ▁of ▁, ▁and ▁built ▁by ▁Elli ott . ▁ ▁Const ruction ▁of ▁the ▁iron cl ad ▁began ▁in ▁January ▁ 1 8 6 3 ▁and ▁continued ▁on ▁during ▁the ▁next ▁year . ▁Word ▁of ▁the ▁gun bo at ▁reached ▁the ▁Union ▁naval ▁officers ▁station ed ▁in ▁the ▁region , ▁raising ▁an ▁alarm . ▁They ▁appe aled ▁to ▁the ▁War ▁Department ▁for ▁an ▁over land ▁expedition ▁to ▁destroy ▁the ▁ship , ▁to ▁be ▁christ ened ▁Alb em ar le ▁after ▁the ▁body ▁of ▁water ▁into ▁which ▁the ▁Ro ano ke ▁em pt ied , ▁but ▁the ▁Union ▁Army ▁never ▁felt ▁it ▁could ▁spare ▁the ▁troops ▁needed ▁to ▁carry ▁out ▁such ▁a ▁mission ; ▁it ▁was ▁a ▁decision ▁that ▁would ▁prove ▁to ▁be ▁very ▁short - s ight ed . ▁ ▁Or dn ance ▁and ▁project iles ▁Alb em ar le ▁was ▁equ ipped ▁with ▁two ▁ ▁Bro oke ▁rif led ▁can non ▁( similar ▁to ▁a ▁Par rott ▁rif le ); ▁each ▁double - band ed