imperial japanese navy technical department

Something about Super-A Cruisers before Maru-5 Project. Source: 早川幸夫，スーパー・クルーザー「超甲巡」覇王伝説，月刊《丸》，2013年5月号 (Monthly "Maru", May 2013). The author stated that in a 1934 document named "Required National Defense Force from Treaty-Break to 1940" (条約決裂後ノ昭和十五年度ニオケル国防所要兵力表), that IJN's original plan...

yeah I bet you can't guess The I-351 and her sister sub the I-352 were laid down as flying boat tender submarines, but converted during construction to tanker subs. Original specifications, design docs and illustrations itt

The Ha-101 class submarines were laid down as transport submarines, but during construction were converted into tanker submarines, small submarine motherships/tenders, and radar picket subs. Any specifications or illustrations of the intended original design would be bussin...

The Ohama and her sister ship Okashi were laid down as target ships, successors to the Hakachi. Ohama was completed as an escort vessel, and Ohashi collided with Yamashio Maru and sunk before completion, but would have been given the same treatment. I can't find any illustrations of their...

The Satsuma class as laid down was intended to mount 12 12 inch guns, with 4 on the centerline and 5 on either side, in a total of 4 twin and 4 single gun turrets. Due to budget issues that the link goes into, the ships got redesigned as semi-dreadnoughts. I can't find any illustrations of the...

Here I gathered all the various cruiser designs and projects proposed for the Imperial Japanese Navy Protected Cruisers: Not found any so far except the cancelled sister ships of the Unebi and Tone classes Light Cruisers: Design C-19 (1912) - A primary mine-layer cruiser design offered before...

For some time I've already made these drawings just not yet posted here. You can now see how the Tosa / Kaga class battleships evolved from an Improved Nagato to as laid down as a 5 turreted similar speed slightly larger battleship. Let us begin: Fast Nagato series: A-115...

It is well known fact that the hull of then under construction battlecruiser IJN Amagi lead ship of her class and which was chosen together with her sister IJN Akagi to become aircraft carriers got seriously damaged during the Great Kanto Earthquake happened in 1923 September 1st. Due to the...

Since the Shinano was sunk unachevied,I think it can count as a project. Regarding the deck paint,it was either a pattern like the one on the unryu class aircraft carrier or a grey deck,depend on the rule the carrier was used. Not all AA was installed on board too. Here are some interpretation ...

http://www.navweaps.com/Weapons/WTJAP_WWII.php#61_cm_%2824%22%29_F3_%28Experimental%29 Came across this again today while trying to find information on possible use by the JSDF of Mark 32 torpedo tubes (built under licence by Watanabe Iron Works) as shore based torpedo launchers. It's...

Not long ago I've finished drawing the various Amagi/Akagi carrier designs I've found in the Hiraga archive. So I post them here now: Amagi Aircraft Carrier Preliminary Design 1 https://www.deviantart.com/tzoli/art/Amagi-Aircraft-Carrier-Preliminary-Design-1-827366018 This is something...

Japanese Wikipedia entry on Akizuki class DD stated that IJN started in 1936 to study dedicated AA vessels following the example of Dido class. They contemplated anything from a 1000 ton torpedo boat armed with a single 10 cm or 12.7 cm AA gun to a quite large cruiser equipped with 12 double...

Taiho was ordered as part of Maru 4 fleet expansion program. She was a compromised design, mating an armored flight deck to a Shokaku size hull, resulting in lower freeboard an reduced hangar capacity. The first, prewar, draft of the subsequent Maru 5 plan included 3 more armored carriers of a...

http://www.armouredcarriers.com/japanese-aircraft-carrier-taiho-armoured-flight-decks/ A nice look at the background of the Taihō-class program in general, along with an detailed overview of IJN Taihō herself. The fact that she doubled as a support carrier, for example, is often overlooked.

Hello people! I'm looking for information about the following projects, some pure paper projects, other more serious proposals never come to fruition: -Kaneda battleship: an alleged 1914 study by Commander Kaneda about an half million ton battleship armed with 100 41cm guns in 50 double turrets...

Hi dear people I know that the Japanese navy was testing the IJN Shimakaze destroyer it stayed by one example, so she was one of a kind. Does somebody know there were more paper project destroyers or a further developed version of the IJN Shimakaze?

Hi people I'm searching for data/drawings of never build Japanese carriers such as the G19 project Hopefully some one can help me on this subject

I've recently found this pretty interesting Japanese Project at the Hiraga Archive. It looks like a hybrid cruiser-carrier warship from 1920's era. There seems to be a few variants mostly by how large the hanger should be and where to locate the conning tower and AA guns. Apart from the unique...

I've found calculations for a 10.000ton cruiser in the Hiraga archives. What is unique about this vessel that it would carry 4 triple 20cm heavily armoured gun turrets, though calculations shows quad turrets were considered as well, but it is unknown if it would carry the same number of such...

I've posted this on another forum but it is better to post many forums to see if anybody know anything about this, I've got hold an extract from a naval forum about possible modernisation plans for the Kawachi class Battleship IJN Settsu which was stripped from her armament after the Washington...