Re: IJS Akagi nd other japanese battleships
The Akagi was, in many ways, already obsolete by the start of World War II. Almost 20 years earlier, she had been built as sort of a "hybrid" ship that was originally designed as a battle cruiser, but later was converted to a carrier. Her wooden deck was supposedly removable to allow for her use as a gun platform, had they ever decided to reverse the conversion. The Akagi was undergunned with an odd flight deck layout - and I suspect that her unconventional port-side superstructure was rather "thin-skinned" (it was an add-on to the original battle cruiser design, and to put a heavy armored superstructure that high off the waterline probably would have created a serious center-of-gravity problem for this ship). These pads made of hammocks or bedrolls might have provided some psychological benefit for the crew, but I doubt that they were of any legitimate ballistic protection. In fact, the Akagi was severely damaged by dive bombers in the Battle of Midway; her wooden deck caught fire and burned uncontrollably. The Akagi was determined to have been damaged beyond repair, so the Japanese navy scuttled her.