Furutaka-class cruiser

Furutaka in 1926. Note the turrets mount only a single gun.
Class overview
Name:	Furutaka class
Operators:	Imperial Japanese Navy
Preceded by:	none
Succeeded by:	Aoba class
In commission:	25 February 1925 - 11 October 1942
Completed:	2
Lost:	2
General characteristics (as per Cruisers of WWII)
Type:	Heavy cruiser
Displacement:	7,100 tons standard; 9,540 tons full load
Length:	185.1 m (607 ft) (overall)
Beam:	16.55 m (54.3 ft)
Draught:	5.56 m (18.2 ft)
Propulsion:	4-shaft Parsons geared turbines 12 Kampon boilers 102,000 shp (76,000 kW)
Speed:	34 1⁄2 knots (63.9 km/h; 39.7 mph)
Range:	6,000 nmi (11,000 km; 6,900 mi) at 14 knots (26 km/h; 16 mph)
Complement:	625
Armament:	(initial) 6 × 20 cm (7.9 in)/50-cal Mark I guns (6 × 1) 4 × 76.2 mm (3 in)/40-cal high-angle guns (4 × 1) 12 × 61 cm (24 in) torpedo tubes (6 × 2) (final) 6 × 8 in (203 mm)/50-cal Mark II gun (3 × 2) 4 × 12 cm (4.7 in)/45-cal high-angle guns (4 × 1) 8 × 25 mm (4 × 2) automatic cannon 8 × 61 cm (24 in) Type 93 torpedo tubes (2 × 4)
Armor:	Belt: 76 mm (3 in) Magazine: 51 mm (2 in) Turrets: 25.4 mm (1 in) Conning tower: none Decks: 35 mm (1.4 in) Upper Decks: 48 mm (1.9 in)
Aircraft carried:	(initial) 1, (final) 2
Aviation facilities:	1 catapult

The Furutaka-class cruisers (古鷹型巡洋艦, Furutaka-gata jun'yōkan^?) were a class of two heavy cruisers which saw service with the Imperial Japanese Navy during World War II. Both vessels of this class were sunk in 1942.

The Furutaka-class cruisers were the first heavy cruisers in the Imperial Japanese Navy (IJN), also referred to as “A class” cruisers by the IJN. Like the cruiser Yūbari, their design was the work of Constructor Captain Yuzuru Hiraga, assisted by Lt. Cmdr. Fujimoto Kikuo.

Designed to beat the U.S. Omaha class and the British Hawkins-class cruisers, they were as fast as the Omahas (and nearly 4 knots faster than the Hawkins class), while firing a heavier broadside, and carrying a larger torpedo battery than either one.

Their flush deck resulted in both weight savings and increased strength by allowing the hull's longitudinal members to be continuous. As with Yūbari, the design featured side and deck armour integrated into the ship's structure, saving additional weight.

Despite the weight-saving efforts, as built Kako was more than 900 tons heavier than its design weight. As a result, draft was increased by more than 1 metre, subsequently reducing top speed, and the height of the belt armour above the waterline. The portholes of the lowest-level crew quarters were near enough to the waterline that they needed to be closed when the ships were at sea, reducing ventilation and making the living spaces less habitable.