▁a ▁fresh ▁phase ▁of ▁work ▁between ▁ 1 8 6 1 ▁and ▁ 1 8 7 4 ▁created ▁si xty - one ▁gun ▁positions ▁in ▁two ▁long , ▁gran ite - fac ed ▁batter ies ▁alongside ▁the ▁older ▁castle . ▁These ▁held ▁very ▁heavy ▁weapons , ▁including ▁massive ▁ 1 2 . 5 ▁in ch , ▁ 3 8 ▁ton ▁( 3 1 7   mm , ▁ 3 9 , 0 0 0   kg ) ▁rif led ▁m uzz le - loading ▁guns . ▁As ▁the ▁century ▁progress ed , ▁these ▁too ▁became ▁out dated ▁and ▁l ighter , ▁quick - f iring ▁guns ▁were ▁installed ▁at ▁the ▁castle ▁to ▁replace ▁them . ▁ ▁The ▁castle ▁formed ▁part ▁of ▁a ▁network ▁of ▁def ences ▁around ▁the ▁entrance ▁to ▁the ▁Sol ent ▁during ▁the ▁First ▁World ▁War , ▁and ▁was ▁re - ar med ▁again ▁during ▁the ▁Second ▁World ▁War . ▁The ▁military ▁de comm ission ed ▁the ▁fort ▁in ▁ 1 9 5 6 ▁and ▁it ▁passed ▁into ▁the ▁control ▁of ▁the ▁Ministry ▁of ▁Works . ▁In ▁the ▁ 2 1 st ▁century , ▁it ▁is ▁run ▁joint ly ▁by ▁English ▁Heritage ▁and ▁the ▁Fri ends ▁of ▁Hur st ▁Castle ▁as ▁a ▁tour ist ▁att raction , ▁receiving ▁around ▁ 4 0 , 0 0 0 ▁visitors ▁during ▁ 2 0 1 5 . ▁Coast al ▁er os ion ▁has ▁become ▁a ▁growing ▁problem ▁despite ▁government ▁inter vention ▁in ▁protect ing ▁the ▁sp it . ▁Four ▁l ighth ouses ▁have ▁been