▁Ne z . ▁St retch ed ▁between ▁the ▁to wers ▁would ▁be ▁improved ▁anti - sub marine ▁n ets ; ▁each ▁tower ▁would ▁be ▁equ ipped ▁with ▁two ▁ 4 - inch ▁guns , ▁search light s ▁and ▁hydro phone ▁detection ▁equipment . ▁Gib b ▁had ▁worked ▁with ▁T ▁G ▁M enz ies ▁and ▁Colonel ▁William ▁Mc L ellan ▁on ▁a ▁sub marine ▁detection ▁system ▁based ▁on ▁a ▁gal van ometer , ▁which ▁was ▁also ▁to ▁be ▁incorpor ated . ▁There ▁would ▁be ▁accommod ation ▁for ▁ 1 0 0 ▁men ▁on ▁each ▁of ▁the ▁to wers . ▁ ▁Const ruction ▁In ▁June ▁ 1 9 1 8 , ▁an ▁advance ▁party ▁of ▁Royal ▁Engine ers ▁arrived ▁at ▁South wick ▁Green ▁in ▁Sus sex ▁where ▁they ▁established ▁a ▁camp . ▁Const ruction ▁of ▁the ▁first ▁two ▁to wers ▁was ▁soon ▁under way ▁on ▁the ▁south ▁side ▁of ▁Sh ore ham ▁har bour ▁nearby , ▁each ▁one ▁consisting ▁of ▁an ▁ 8 0 ▁feet ▁( 2 5 ▁metres ) ▁high ▁rein for ced ▁concrete ▁ra ft ▁made ▁from ▁inter lock ing ▁cells , ▁sur mount ed ▁by ▁a ▁ 1 , 0 0 0 ▁ton ▁steel ▁column ▁ 9 0 ▁feet ▁( 2 7 . 5 m ) ▁high ▁and ▁ 4 0 ▁feet ▁( 1 2 m ) ▁wide . ▁The ▁cost ▁of ▁the ▁whole ▁project ▁was ▁£ 1 2 ▁million , ▁an ▁enorm ous ▁sum ▁for ▁the ▁time . ▁The ▁to wers ▁became ▁visible ▁for ▁many ▁miles ▁around ▁and ▁were ▁known ▁locally