▁Union ▁Army ▁under ▁U ly ss es ▁S . ▁Grant ▁attempt ▁to ▁complete ▁the ▁opening ▁of ▁the ▁river . ▁ ▁The ▁poor ▁performance ▁of ▁the ▁River ▁Def ense ▁Fle et , ▁both ▁at ▁M emph is ▁and ▁at ▁the ▁earlier ▁Battle ▁of ▁New ▁Orleans , ▁was ▁the ▁final ▁demonstr ation ▁that ▁naval ▁operations ▁had ▁to ▁be ▁commanded ▁by ▁trained ▁profession als ▁subject ▁to ▁military ▁discipline . ▁The ▁El let ▁R ams ▁remained ▁in ▁federal ▁service , ▁but ▁they ▁had ▁no ▁other ▁opportunity ▁for ▁combat ▁of ▁the ▁sort ▁for ▁which ▁they ▁were ▁intended . ▁They ▁were ▁soon ▁transformed ▁into ▁an ▁am ph ib ious ▁ra iding ▁body , ▁the ▁Mississippi ▁Marine ▁Brigade ▁( with ▁no ▁connection ▁to ▁the ▁United ▁States ▁Marine ▁Corps ), ▁led ▁by ▁El let ' s ▁brother , ▁Lieutenant ▁Colonel ▁( l ater ▁Brig ad ier ▁General ) ▁Alfred ▁W . ▁El let . ▁The ▁demand ▁for ▁increased ▁professional ism ▁also ▁resulted ▁in ▁the ▁elim ination ▁of ▁private ering , ▁although ▁the ▁River ▁Def ense ▁Fle et ▁was ▁not ▁composed ▁of ▁private ers ▁in ▁the ▁usual ▁meaning ▁of ▁the ▁term . ▁ ▁The ▁battle ▁remains ▁a ▁ca ution ary ▁tale , ▁demonstr ating ▁the ▁ill ▁effects ▁of ▁a ▁poor ▁command ▁structure . ▁It ▁is ▁also ▁one ▁of ▁only ▁two ▁purely ▁naval ▁batt les ▁of ▁the ▁war , ▁ex cluding ▁single - ship ▁actions , ▁and ▁took ▁place ▁ ▁from ▁the ▁nearest ▁open ▁water . ▁The ▁other ▁was ▁the ▁Battle ▁of ▁Pl um ▁Point ▁B end , ▁also ▁on ▁the ▁Mississippi .