Losses accumulated in the Pacific Theater by the USN and IJN

[Submarine_Wahoo]

As a pet project, I collected information on the losses that were obtained throughout the Pacific Theater (December 1941 to August 1945), focusing on the United States Navy and Imperial Japanese Navy. After two weeks of work, in between other obligations that I have, I finally finished compiling this information.

 

 

* Losses are defined here as any vessel that have been put out of service due to battle damage, capture by enemy forces, scuttling as a result of battle damage or to prevent capture by enemy forces, or by accident (collisions, beaching, etc.) by a belligerent acting within the Pacific Theater. Ships that are presumed lost are included. For the USN, accidents that occurred along the Atlantic coast (within American territorial waters) are included, but losses by German submarine along the Atlantic coast is excluded. Losses sustained by the IJN due to other combatants, such as the Royal Navy, are included. Ship losses sustained by the IJA are excluded.

 

** Warships counted include ships that are designated as transports and auxiliaries and capable of moving under their own power.

 

Here are events that help explain the values:

• December 41 - Pearl Harbor
• May 42 - Coral Sea, Corregidor (a number of USN vessels were scuttled at anchor)
• June 42 - Midway
• November 42 - Guadalcanal
• April 43 - Operation I-Go
• June 43 - Mutsu exploded (seriously: constitutes the vast majority of tonnage lost this month)
• July 43 - Empress Augusta Bay
• November 43 - Tarawa
• February 44 - Truk
• June 44 - Philippine Sea
• October 44 - Leyte Gulf
• November 44 - Ormoc Bay
• February 45 - Iwo Jima (to March 45)
• March 45 - Okinawa (to June 45)
• April 45 - Operation Ten-Go
• July 45 - Kure

 

Some preliminary analysis:

• The IJN lost 687 warships, amounting to 1,964,621 tons of warships. The USN lost 402 ships, amounting to approximately 769,559 tons of warships. The losses sustained by both navies amounts to a tonnage lost ratio of 2.55:1 (IJN to USN).
• 49.55% of all IJN losses occurred in 1944 while 39.10% of all USN losses occurred in 1942. USN losses remained fairly consistent throughout the war, after the initial setbacks in 1942, oscillating around 16% of the final total losses.

 

Further analysis:

 

Some personal observations:

• I was surprised by the number of USN warships that were lost as a result of accidents. I do not have a definitive tally of the number of warships lost as marine casualty, but it came up very frequently in my research. Most IJN warships were lost in action: whether that is due to better sailoring or because the USN is that good at sinking things is not distinguishable here.
• Sinking by kamikaze attack ramped up significantly in the final months.
• By tonnage, USN losses in the Leyte Gulf is less than at Pearl Harbor. That's extremely impressive for one of the largest naval battles in history.
• The Yamato-class battleship itself is worth more than all of the USN ships sunk at Guadalcanal, at 63k tons.

 

Notes on the data:

• All warships are counted using the lightest displacement that I am aware of. Because it is cumbersome to search for records of the amount of materials were on board the sunken vessels, I opted to assume that all ships are at their lightest displacement.
• The USN information is as complete as I can make it. A number of ships have very little information available, such as lacking displacement information, so I chose to not appropriate a displacement to them.

 

Sources:

• BlueJacket for USN information
• Ibiblio for IJN information
• NavSource for USN information

 

Special thanks to the Library of Congress for helping me with sources.

[Carrier_Hiyou]

Thank you for your hard work Atago. The losses the IJN took are so staggering especially when the USN established air superiority.  

[Cruiser_Kiso]

Very intresting and thorough +1

[IgnoramBus]

That's a great read and now I have to read all those wiki pages because reasons....

[Big_Spud]

Yeah, that looks about right.

 

Can really see Kirishima and Hiei's tonnage there at Guadalcanal.

[Submarine_Wahoo]

Yeah, that looks about right.

 

Can really see Kirishima and Hiei's tonnage there at Guadalcanal.

 

Yep: they consist of over half of the tonnage lost in November 42.

[Fog_Heavy_Cruiser_Chokai]

Dang after '42 the IJN was always on the losing end, except for August '43. Nothing short of amazing. Great work Atago! Next time I get into a WW2 Argument (which I do... often) I will bring this up!

[Submarine_Wahoo]

Dang after '42 the IJN was always on the losing end, except for August '43. Nothing short of amazing. Great work Atago! Next time I get into a WW2 Argument (which I do... often) I will bring this up!

 

August 43 was the Battle of Tarawa, which Japan lost nearly their entire garrison defending. However, the Americans paid heavily for their success. I'll add it to the list of events.

 

EDIT: My mistake: Tarawa was a November 43 conflict.

[ironeagle2006]

Read up on the Japanese Cargo Shipping losses you can tell the Difference between when the Young and Willing to Attack Commanders took over Plus when the USN got the Torpedoes fixed compared to the start of the War.  We went from 50-90K tons of ships sunk to 300K Tons SUNK plus whatever IJN Capital Ships they blew out of the water.  

[Jjtt0105]

nice

[Submarine_Wahoo]

Relatively small update: I added some pie charts to show the percentage of tonnage lost per year for both navies. The years match color so that you can compare the two.

[SeaRaptor]

Is this warship tonnage exclusively?

[Submarine_Wahoo]

On 10/19/2015 at 12:43 PM, SeaRaptor00 said:

Is this warship tonnage exclusively?

 

No, it includes all vessels that were commissioned by both navies. See in my OP the following line: ** Warships counted include ships that are designated as transports and auxiliaries and capable of moving under their own power. Basically, the chart is counting all ships and boats that were commissioned by both navies to directly influence the war campaign.