The
Monmouths were intended to protect British merchant shipping from fast
cruisers like the French , or the . The ships were designed to
displace . They had an
overall length of , a
beam of and a deep
draught of . They were powered by two 4-cylinder
triple-expansion steam engines, each driving one shaft using steam provided by 31
Belleville boilers. The engines produced a total of which was designed to give the ships a maximum speed of . The ship carried a maximum of of coal and her complement consisted of 678 officers and
ratings. The
Monmouth-class ships' main armament consisted of fourteen
breech-loading (BL) Mk VII guns. Four of these guns were mounted in two twin-
gun turrets, one each fore and aft of the
superstructure, and the others were positioned in
casemates amidships. Six of these were mounted on the
main deck and were only usable in calm weather. Ten
quick-firing (QF) 12-pounder () 12-cwt guns were fitted for defence against
torpedo boats. The ship's
waterline armour belt was thick
amidships and forward. The armour of the gun turrets, their
barbettes and the casemates was four inches thick. The protective
deck armour ranged in thickness from and the
conning tower was protected by of armour. ==Construction and service==