Imperial Japanese Navy (IJN) Kaga 加賀 was a Japanese aircraft carrier that was in service from 1928 to 1942. It was originally designed as a Tosa-Class battlecruiser, but construction as such was not finished due to the signing of the Washington Naval Treaty in 1922. In 1928, the incomplete hull was repurposed and used to build an aircraft carrier.

Kaga had an overall length of 238.5 meters, a beam of 31.67 meters, a draft of 7.92 meters, a maximum speed of 28 knots, and a range of 12,000 miles at 15 knots. It had a complement of approximately 1,700 personnel and 90 aircraft.

Kaga took part in several operations during World War II, including the attack on Pearl Harbor on December 7, 1942, the Battle of Rabaul on January 20, 1942, and the Battle of Midway from June 4-7, 1942. On the morning of June 4, 1942, twenty-five Douglas SBD Dauntlesses from the USS Enterprise bombarded Kaga, landing at least four bomb hits. Two bombs struck elevators on the forward and aft sections of the upper hangar; another struck the island and destroyed the bridge. The final bomb struck at amidships and penetrated the flight decks, causing a series of explosions from the 80,000 lbs of munitions. Later that day, the IJN destroyer Hagikaze scuttled Kaga with two torpedoes, sinking the carrier.

On September 12, 2023, Ocean Exploration Trust and partners surveyed Kaga during the Ala ‘Aumoana Kai Uli expedition, which was funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute. At the time, Kaga was intact, but disarticulated, and embedded in seafloor sediment. Extensive damage was noted on the remaining deck levels. Off the starboard side of the wreck site is a debris field with possible remnants of one of the three flight decks.

17 hours of video was collected of Kaga  using remotely operated vehicle Atalanta. The video was processed into still images and color corrected using Adobe Photoshop 2024. 20,946 images were used to create nine photo models of the site: the port side (3), the stern (1), the bow (1), the starboard side (1), and the debris field off the starboard side of the site (3). These individual models were stitched together in Rhinoceros 8.

The full annotated video of this dive can be viewed on SeaTube.

Site Name: IJN Kaga

Type: UCH

UCH Vessel Date Built: March 31, 1928

UCH Vessel Date Sank: June 4, 1942

Hull Material: Steel

Official Number: N/A

Expedition Number: NA154

Expedition Name: Ala ‘Aumoana Kai Uli

ROV Dive Number: T1003

ROV Dive Date: September 12, 2023

Location: Hawai‘i

Depth: 5 kilometers

Length: 238.5 meters

Width: 31.7 meters

ROV Used: Atalanta

Camera Information: Insite Mini-Zeus HD

Video or Stills: Video

Number of Images Used/Format: 20,946/JPG

Image Alignment Percentage: 92%

Number of Tie Points: 2,802,068

Link to Raw Video Footage: Link to come

Time to Complete: 78

Orthomosaic Views Available: No

Images Available: Yes

Animations Available: Yes

Available File Exports/Location/POC:

Links to Model:

Link to NOAA Ocean Exploration Project Page:

Software: Agisoft Metashape Professional Version 2.1.0, Rhinoceros 8

Developer: Raymond Phipps, NOAA Ocean Exploration explorer-in-training, May 28, 2024.

Credit: Model courtesy of Ocean Exploration Trust/NOAA Ocean Exploration, NA154 Ala ‘Aumoana Kai Uli expedition.