5 - class ▁monitor . ▁After ▁service ▁in ▁the ▁Mediter rane an ▁and ▁the ▁D over ▁Pat rol , ▁she ▁was ▁also ▁served ▁in ▁the ▁British ▁inter vention ▁in ▁Russia ▁in ▁ 1 9 1 9 . ▁Convert ed ▁to ▁the ▁R N V R ▁dr ill ship ▁Cla ver house ▁in ▁ 1 9 2 2 , ▁she ▁served ▁in ▁that ▁capacity ▁at ▁" Le ith " ▁until ▁ 1 9 5 8 . ▁ ▁Design ▁Int ended ▁as ▁a ▁shore ▁bomb ard ment ▁vessel , ▁M 2 3 s ▁primary ▁arm ament ▁was ▁a ▁single ▁ 9 . 2 ▁in ch ▁M k ▁VI ▁gun ▁removed ▁from ▁the ▁ ▁HMS ▁G raft on . ▁In ▁addition ▁to ▁her ▁ 9 . 2 - inch ▁gun , ▁she ▁also ▁possessed ▁one ▁ 1 2 ▁p ound er ▁and ▁one ▁six ▁p ound ▁anti - air craft ▁gun . ▁She ▁was ▁equ ipped ▁with ▁a ▁four - sh aft ▁Bol inder ▁four - cy l inder ▁semi - d ies el ▁engine ▁with ▁ 6 4 0 ▁horse power ▁that ▁allowed ▁a ▁top ▁speed ▁of ▁eleven ▁kn ots . ▁The ▁monitor ' s ▁crew ▁consisted ▁of ▁si xty - n ine ▁officers ▁and ▁men . ▁ ▁Const ruction ▁HMS ▁M 2 3 ▁ordered ▁in ▁March , ▁ 1 9 1 5 , ▁as ▁part ▁of ▁the ▁War ▁Emer gency ▁Program me ▁of ▁ship ▁construction . ▁She ▁was ▁laid ▁down ▁at ▁the ▁Sir ▁Ray l ton ▁D ixon ▁& ▁Co . ▁Ltd ▁ship yard