The Zealandian Senate had hobbled the Zealandian Admiralty, refusing their requests to build a pair of Heavy Cruisers to match what the rest of the world was building. The Zealandian Navy had been forced to accept four very light cruisers instead (see Tower Class). 1929 and members of the Senate friendly to the Navy advised to get the designs and plans ready for a pair of Heavy cruisers as the Senate would pass the acquisition bill in 1930.
Design work began and the decision was taken to use a flush deck hull for these large ships. The British triple 8" turret and gun system would be used to arm the vessels with 3 turrets, two forward and one aft. The new twin 4" AA guns would be fitted (5 mountings). Quad 2 pounder would provide the multi-gun AA batteries, while the Hispano 20mm provided the light cannon AA. Torpedo tubes and aircraft handling facilities were fitted amidships.
It was in the speed department that some extra emphasis was placed. Large geared turbine engines and boilers together put out 110,000 shaft horsepower for 33 knots. With overload and a flat calm both ships managed just over 34 knots on trials in light condition. In full load condition both ships managed to make their 32 knots easily.
Being modern ships, little was done between commissioning and the start of World War Two. On start of war the ships were continually updated with better electronics and light AA weapons. 20mm Oerlikons replaced the Hispanos, and more were added in twin and single mountings. The 2 pounder count was doubled with two more quad mountings beings added around the aft superstructure. The 4 quads were removed in 1942 and replaced with four quad 40mm mountings. The extra topweight being added was in some ways countered by the removal of the aircraft handling facilities and torpedo tubes.
