of the contract signed with Vickers in November 1910, one member of the Kongō class—the lead ship Kongō—was to be built in Britain and Vickers was to maximize the transfer of naval technology to Japan. The design of the ships was from Vickers Design 472C (corresponding to the Japanese design designation B-46). The original design, which is commonly known as "Ishizuchi" featured ten 12-inch (304.8 mm) 50-calibre guns, sixteen guns, and eight torpedo tubes. Commander Katô Hirohasu pushed for the adoption of a new /45 calibre gun that was currently under development. After trials of the new gun, which were witnessed by both the Japanese Navy and Royal Navy, the Japanese made the decision on 29 Nov 1911 to use the new gun despite the keel having already been laid down on 17 January 1911, and the resulting need to quickly make a large number of alterations to the design, so as to not prolong the construction. Due to the size of the guns, only 8 were installed, and a plane installed in place of an extra turret. The final design of the battlecruisers resulted in an improved version of the , displacing an estimated 27,940 tonnes (27,500 long tons). It also called for eight 14-inch guns mounted in four twin gun turrets (two forward and two aft) with a top speed of . To ensure transfer of the latest design knowledge to Japan more than 100 technical specialists were sent on 18 months secondments from Japan to Vickers during the construction phase of Kongō. If superintendents, supervisors and trial witnesses are also included then about 200 Japanese spent time in Britain. Description The ships had a length of overall and a beam of . They had a draft of and displaced at normal load. Propulsion The Kongō-class ships had two sets of Parsons direct-drive steam turbines, except for Harunas Brown-Curtis turbines, each of which drove two propeller shafts. The high-pressure turbines drove the wing shafts while the low-pressure turbines drove the inner shafts. The turbines were arranged in two compartments, separated by a centerline longitudinal bulkhead; both compartments were situated between turrets No. 3 and 4. They were designed to produce a total of , using steam provided by 36 Yarrow or Kampon water-tube boilers, with working pressures ranging from . The boilers, arranged in eight compartments, were mixed-firing with fuel oil sprayed onto the coal for extra power.