▁in ch , ▁ 3 8 ▁ton ▁( 3 1 7   mm , ▁ 3 9 , 0 0 0   kg ) ▁rif led ▁m uzz le - loading ▁( R ML ) ▁guns , ▁fifteen ▁ 1 0 ▁in ch , ▁ 1 8 ▁ton ▁( 2 5 4   mm , ▁ 1 8 , 0 0 0   kg ) ▁R ML ▁guns , ▁five ▁ 9 ▁in ch , ▁ 1 2 ▁ton ▁( 2 2 8   mm , ▁ 1 2 , 0 0 0   kg ) ▁R ML ▁guns , ▁and ▁ 3 ▁ 6 4 - p ound ers ▁( 2 9   kg ), ▁together ▁forming ▁a ▁powerful ▁ar sen al . ▁ ▁Two ▁new ▁l ighth ouses ▁were ▁constructed ▁in ▁the ▁ 1 8 6 0 s . ▁The ▁first ▁was ▁the ▁" L ow ▁Light " ▁built ▁into ▁the ▁rear ▁wall ▁of ▁the ▁west ▁wing ▁of ▁the ▁castle . ▁The ▁second ▁l ighth ouse ▁was ▁the ▁" High ▁Light " ▁– ▁the ▁free ▁standing ▁Hur st ▁Point ▁L ighth ouse ▁built ▁on ▁the ▁end ▁of ▁Hur st ▁Sp it ▁between ▁ 1 8 6 5 ▁and ▁ 1 8 6 7 . ▁A ▁new ▁public ▁house , ▁the ▁Castle ▁Inn , ▁was ▁established ▁on ▁the ▁north ▁end ▁of ▁the ▁sp it . ▁A ▁narrow - g au ge ▁railway ▁was ▁constructed ▁in ▁the ▁ 1 8 8 0 s ▁to ▁move ▁supplies ▁into ▁the ▁castle . ▁ ▁By ▁the