Mogami-class cruiser

File:Mogami-1.jpg

For the 1931 Fleet Replenishment Program, believing themselves understrength in cruisers, the IJN chose to build to the maximum allowed by the Washington Naval Treaty. This resulted in the choice of {{convert|155|mm|1|abbr=on}} guns in five triple turrets (a first for Japan) in the Mogamis, also capable of 55° elevation, making the Mogamis one of the very few classes of cruiser to have a dual purpose (DP) main battery; this was coupled with very heavy anti-aircraft protection, as well as the standard reloadable, turreted torpedo launchers, also unique to the IJN.Lacroix, pp. 434–435

To save weight and improve transverse stability, the class was given a more compact and lower superstructure, made of aluminium, which was welded rather than riveted.Lacroix, pp. 438–439 Only ten boilers could be fit under the weight limits (compared to twelve in the previous {{sclass|Takao|cruiser|5}} and {{sclass|Myōkō|cruiser|5}} classes), and the chimney arrangement was designed to minimize weight as well; the middle funnel featured no chimney of its own, instead venting its exhaust gasses into the underside of the forward chimney, which itself was reclined from its base so that, at its top, it merged with the aft funnel's chimney. The new geared impulse turbines added {{convert|22,000|shp|kW|lk=in}} over Atago, increasing the top speed by {{convert|1.5|kn|lk=in}}. Protection, however, was not stinted on; the class proved able to take substantial punishment.

The declared weight was 8,500 tons, though the true design weight was 9,500 and at trials they would displace 11,169 tons.Brown, p. 74 “They must be building their ships out of cardboard or lying” said the Royal Navy’s Director of Naval Construction (DNC) in 1935 when briefed by Naval Intelligence about the public displacement figure announced by the Japanese.[https://naval-encyclopedia.com/ww2/japan/mogami-class-cruisers.php Naval Encyclopedia. "Mogami class cruisers (1934)" retrieved November 2, 2023.]

The designers, however, had overreached; excessive topweight led to instability, and gunnery trials revealed cracking hull welds. Hull bulges were retrofitted to Mogami and Mikuma, and added to Kumano and Suzuya, increasing beam to {{convert|20.5|m|ft|abbr=on}} and displacement to 11,200 tons, cutting speed by {{convert|2|kn}}.Lacroix, pp. 439–442

Following Japan's withdrawal from the Second London Naval Treaty, plans were made to modernize and expand the entire fleet. Beginning in 1939, the class was brought in for substantial reconstruction, replacing the triple 155 mm turrets with twin 203 mm (8-inch) guns, turning over the 155 mm turrets for the battleships of the {{sclass|Yamato|battleship|4}}.Lacroix, pp. 442–443 Indeed, the designers had designed the class in mind so that the 6-inch guns could be switched with 8-inch batteries, in effect making them heavy cruisers and skirting the London Naval Treaty, though the Japanese had withdrawn from the conference and were not signatories to the Second London Naval Treaty of 1936.

Torpedo bulges were also added; in all, displacement rose to over 13,000 tons, and speed dropped to {{convert|35|kn}}.

File:Japanese Cruisers of the Seventh Squadron.jpg, 1938.]]

All four ships participated in the Japanese invasion of the Dutch East Indies. Mogami and Mikuma were present at the Battle of Sunda Strait and contributed to the sinkings of the cruisers {{HMAS|Perth|1934|6}} and {{USS|Houston|CA-30|6}}.

In June 1942, all four took part in the Battle of Midway, where Mogami and Mikuma collided trying to avoid a submarine attack; Mikuma was finished off on 6 June 1942 by aircraft from aircraft carriers {{USS|Enterprise|CV-6|6}} and {{USS|Hornet|CV-8|2}}. The heavily damaged Mogami limped home and spent ten months in yard, during which her afterparts were completely rebuilt, and "X" and "Y" turrets were replaced by a flight deck (with the intention to operate 11 aircraft).

In October 1944, the survivors were reunited at the Battle of Leyte Gulf. Mogami, heavily damaged by a collision with the cruiser {{ship|Japanese cruiser|Nachi||2}}, cruiser gunfire, and aerial attack, was scuttled by the destroyer {{ship|Japanese destroyer|Akebono|1930|2}}, while Kumano limped into Manila harbor on one boiler, to be sunk by Halsey's aviators on 25 November 1944; the US escort carrier planes mauled Suzuya at Leyte, which was scuttled by the destroyer {{ship|Japanese destroyer|Okinami||2}} on 25 October.

{{Reflist|30em}}

• {{cite book

| last = Blair

| first = Clay

| year = 1975

| title = Silent Victory

| url = https://archive.org/details/silentvictoryuss00blai

| url-access = registration

| publisher = Lippincott

| location = London

}}

• {{cite book

| last = Dull

| first = Paul S.

| year = 1978

| title = A Battle History of the Imperial Japanese Navy, 1941-1945

| publisher = Naval Institute Press

| location = Annapolis, Maryland

| isbn = 0-87021-097-1

| url-access = registration

| url = https://archive.org/details/battlehistoryofi0000dull

}}

• {{cite book|last= Jentschura|first= Hansgeorg|first2= Dieter |last2=Jung|first3=Peter |last3=Mickel| year= 1977|title= Warships of the Imperial Japanese Navy, 1869–1945|publisher= United States Naval Institute| location= Annapolis, Maryland|isbn = 0-87021-893-X|name-list-style=amp}}
• {{cite book

| last1 = Lacroix

| first1 = Eric

| first2 = Linton

| last2= Wells II

| year = 1997

| title = Japanese Cruisers of the Pacific War

| publisher = Naval Institute Press

| location = Annapolis

| isbn = 0-87021-311-3

| oclc= 21079856

}}

• {{cite book

| last = Preston

| first = Antony

| year = 2004

| title = World's Worst Warships

| publisher = Conway's Maritime Press

| location = London

}}

• {{cite book|last=Rohwer|first=Jürgen|title=Chronology of the War at Sea 1939–1945: The Naval History of World War Two|publisher=Naval Institute Press|location=Annapolis, Maryland|year=2005|edition=Third Revised|isbn=1-59114-119-2 |author-link=Jürgen Rohwer}}
• {{cite book|title=Conway's All the World's Fighting Ships 1922–1946|editor1-last=Chesneau|editor1-first=Roger|publisher=Conway Maritime Press|location=Greenwich, UK|year=1980 |isbn=0-85177-146-7 |chapter=Japan |author-first=Ian|author-last=Sturton}}
• {{cite book|last=Whitley|first=M. J.|title=Cruisers of World War Two: An International Encyclopedia |publisher=Cassell |location=London|year=1995|isbn=1-86019-874-0|author-link=Michael J. Whitley}}

{{Commons category|Mogami class cruiser}}

• {{cite web

| last = Hackett

| first = Bob

|author2=Sander Kingsepp

| year = 2006

| url = http://www.combinedfleet.com/mogami_c.htm

| title = Mogami class

| work = Imperial Japanese Navy Page (Combinedfleet.com)

| access-date = 2006-06-14

}}

{{Mogami class cruiser}}

{{WWII Japanese ships}}{{Treaty Cruisers}}

Category:Cruiser classes

Category:Cruisers of the Imperial Japanese Navy

Category:Ships built in Japan