▁was ▁driven ▁by ▁a ▁ ▁electric ▁motor . ▁They ▁could ▁reach ▁ ▁on ▁the ▁surface ▁and ▁ ▁under water . ▁On ▁the ▁surface , ▁the ▁third - batch ▁boats ▁had ▁a ▁range ▁of ▁ ▁at ▁ ▁and ▁ ▁at ▁ ▁sub mer ged . ▁ ▁The ▁boats ▁were ▁armed ▁with ▁seven ▁ 2 1 - inch ▁( 5 3 3 ▁mm ) ▁tor ped o ▁tub es . ▁Six ▁of ▁these ▁were ▁in ▁the ▁bow , ▁and ▁one ▁external ▁t ube ▁was ▁mounted ▁in ▁the ▁stern . ▁They ▁carried ▁six ▁reload ▁tor ped o es ▁for ▁the ▁bow ▁tub es ▁for ▁a ▁total ▁of ▁th ir teen ▁tor ped o es . ▁Tw elve ▁mines ▁could ▁be ▁carried ▁in ▁lieu ▁of ▁the ▁internally ▁st owed ▁tor ped o es . ▁They ▁were ▁also ▁armed ▁with ▁a ▁ 3 - inch ▁( 7 6   mm ) ▁deck ▁gun . ▁It ▁is ▁uncertain ▁if ▁S ick le ▁was ▁completed ▁with ▁a ▁ ▁O er lik on ▁light ▁AA ▁gun ▁or ▁had ▁one ▁added ▁later . ▁The ▁third - batch ▁S - class ▁boats ▁were ▁fitted ▁with ▁either ▁a ▁Type ▁ 1 2 9 AR ▁or ▁ 1 3 8 ▁AS D IC ▁system ▁and ▁a ▁Type ▁ 2 9 1 ▁or ▁ 2 9 1 W ▁early - warning ▁rad ar . ▁ ▁Const ruction ▁and ▁career ▁HMS ▁S ick le ▁was ▁a ▁third - group ▁S - class ▁sub marine ▁and ▁was ▁ordered ▁by ▁the ▁British ▁Admir alty ▁on ▁ 2 ▁September ▁