Niteroi Class Heavy Cruiser.
Once the Admiralty had time to take stock of what was under construction, what
had been halted on outbreak of war, and what was still needed to be ordered,
they found the Brazilian order for six H/I type of destroyers, and one heavy
cruiser of an improved Sirius type. It may be hard to envision an improved
Sirius with its 16x6", but Armstrong Whitworth had tried very hard. The
Brazilian cruiser had been launched as the BNS Niteroi and was 75% complete at
the outbreak of war when construction was suspended. At 640x72 feet the ship was
not huge but the armament, armour and propulsion pushed it out to over 14,000
tons standard and 18,000 tons full load. The main armament of 12x8" gave it an
advantage over any cruiser then in existence. Which was what it was supposed to
do as the Argentinians had a cruiser under construction in Germany at the same
time. Armour was also made to protect the ship against the same ship with 6"
side armour and 3.5" of deck armour. Propulsion had not been stinted either with
120,000shp for 32 knots.
In early 1940 the Niteroi was purchased from the Brazilians and work on the ship
recommenced. The ship being renamed Agamemnon. Completion was slated for late
1941, with new specifications for the electronics suite which the ship would not
have originally been built with. The RN was not willing to give away its new
toys to anybody. The main armament of 12x8" was a strange one for the RN as the
rest of its heavy cruisers were armed with 7.5" guns. AW's had forseen that in
the original specs by making the guns able to take US pattern 8" shells. The
lesser armament had not been forgotten, 12x4" dual purpose guns with 16x2pd and
18x20mm AA weapons. British ships were still mounting torpedoes and two triple
mountings of 21" were fitted.