About the book:
The third and last volume of the outline history of the design, construction and operations of the Japanese ironclads, battleships and battle cruisers is devoted to the Imperial Japanese Navy’s (IJN) masterpiece in these categories – the Yamato class. However, before dealing with this class in some detail it is considered convenient to describe (1) the Tosa experiments in 1924 and (2) the Kongō replacement designs by Fujimoto Kikuo and Hiraga Yuzuru in 1929. The reason for taking up these two items is the influence they exerted upon the Yamato class in respect to the protection below and above the waterline and the application of the concentrated protection method favoured by Hiraga. Here implemented to the extreme.
Another noteworthy point is Hiraga’s complete turn away from the curved longitudinal torpedo bulkhead, which he earlier favoured, in favour of an inclined armoured torpedo bulkhead as a continuation of the also inclined hull side armour. A comparison of the amidships section of the Hiraga design and that of the Yamato class prove striking correspondences. The new torpedo protection formula was the result of the effect of the large calibre underwater trajectory projectile that the IJN experienced in the course of the Tosa experiments, and which the IJN believed to be unknown to other naval powers. As a consequence underwater protection was calculated primarily against the impact and detonation of large calibre armour-piercing shells, with the thought that the formula also covered torpedo detonations.