▁n avy , ▁being ▁power ed ▁both ▁by ▁sail ▁and ▁steam . ▁An ▁early ▁steam - power ed ▁ship , ▁she ▁was ▁still ▁fitted ▁with ▁tower ing ▁m asts ▁and ▁trim ▁square - set ▁yards , ▁and ▁was ▁the ▁flags hip ▁of ▁Sir ▁Charles ▁Nap ier . ▁ ▁Design ▁and ▁construction ▁First ▁christ ened ▁HMS ▁W inds or ▁Castle , ▁she ▁was ▁the ▁first ▁of ▁a ▁class ▁of ▁four ▁that ▁represented ▁the ▁ult imate ▁development ▁of ▁the ▁wooden ▁three - de cker ▁ship ▁of ▁the ▁line ▁which ▁had ▁been ▁the ▁main st ay ▁capital ▁ship ▁in ▁naval ▁war fare ▁for ▁ 2 0 0 ▁years . ▁She ▁was ▁originally ▁ordered ▁in ▁ 1 8 4 1 ▁to ▁a ▁design ▁of ▁Sir ▁William ▁Sym onds , ▁the ▁Survey or ▁of ▁the ▁Navy , ▁but ▁was ▁not ▁laid ▁down ▁until ▁May ▁ 1 8 4 9 ▁at ▁P embro ke ▁D ock ▁by ▁which ▁time ▁Sym onds ▁had ▁res igned ▁and ▁the ▁design ▁had ▁been ▁modified ▁by ▁the ▁Ass istant ▁Survey or ▁John ▁Ed ye . ▁At ▁this ▁stage ▁the ▁ship ▁was ▁still ▁intended ▁as ▁a ▁sail ing ▁vessel . ▁Although ▁the ▁Royal ▁Navy ▁had ▁been ▁using ▁steam ▁power ▁in ▁smaller ▁ships ▁for ▁three ▁dec ades , ▁it ▁had ▁not ▁been ▁adopted ▁for ▁ships ▁of ▁the ▁line , ▁partly ▁because ▁the ▁enorm ous ▁p addle - box es ▁required ▁would ▁have ▁meant ▁a ▁severe ▁reduction ▁in ▁the ▁number ▁of ▁guns ▁carried . ▁This ▁problem ▁was ▁solved ▁by ▁the ▁ad option ▁of ▁the ▁sc rew ▁prop