[May 2022 Restart] Two multibeam sonars and an unmanned submersible will take us to the wreck of submarine "Albacore"

Research Background

The purpose of the Society La Plongée for Deep Sea Technology, which was established in 2017, is to “research the deep sea for scientific and technical activities, and conduct activities related to dissemination and promotion of undersea activities including deep sea such as undersea observation and development of equipment.” The Society will contribute to the improvement of the people's understanding of the ocean.

In August 2017, the society operated a remotely operated vehicle (ROV) to survey 24 submarines that had been abandoned by the U. S. navy off the Goto Islands, and showed the current features of the submarines about 70 years after the Pacific War. Then, in 2018, we discovered three additional submarines, including a U-boat (U-511, which was given to Japan and renamed as "Ro 500"), that were also abandoned in Wakasa Bay, and the wartime conscription ship "Taiyo Maru" in the East China Sea. Furthermore, in 2021, we investigated the "B-29" bomber that crashed in Tokyo Bay.

Using our technology, we reintroduced the history of those vessels sleeping in the deep sea. And we also deepened the general public's understanding of the ocean and related technology. Based on these successful results, we will proceed with the next survey. The submarine "Albacore (SS-218)," that we are going to investigate this time is the 7th Gato-class submarine that was built in the U. S. Navy during the Pacific Wars. She was lost, probably by a mine, on November 7th, 1944, off the coast of Esan, Hokkaido.

Of all the sunken ships, why the "Albacore"?

When the approximate location of a sunken ship on the seafloor is not known, it is necessary to survey a wide area of ocean for a long time by the Multi-Beam Echo Sounder (MBES). When the water is deep, the horizontal resolution of the survey data becomes poorer, making it difficult to determine whether it is a ship or simply an irregularity on the seafloor. Furthermore, searching deeper water areas requires a large ROV, which in turn requires a large vessel to deploy it.

Considering these restrictions against the cost of the project and narrowed down the target for this survey. As a result, we chose the Albacore as our fifth target because the location of the sinking has already been roughly narrowed down and the depth to the seafloor is about 200 meters. Albacore is also a notable submarine, having sunk the aircraft carrier Taiho, the light cruiser Tenryu, and the destroyers Oshio and Sazanami.

The United States lost 52 submarines during World War II. The photo is an inscription at the Pacific War Museum in Texas. Pacific Fleet Commander Nimitz wrote the deeds and roll call of submarines on "Eternal Patrol." Eleven submarines have been discovered: Grayback (SS-208) was discovered as the 11th (http://www.lost52project.org/index.html) off Okinawa in June 2019. Albacore is still in Eternal Patrol.
By the way, Japan lost 127 submarines during the Pacific War, and 58 remained and were destroyed after the war. We have identified 27 submarines that were abandoned in the ocean after the war.

Seafloor survey using multibeam sonar is the first step in seafloor exploration activities.

The following flow is planned for the Albacore survey plan. First, the seafloor topography around the presumed sinking location is measured by the MBES to find out irregular protrusions. Two support vessels (fishing boats belonging to the Todohokke Fisherman's Cooperative Association) will be chartered, and MBES transducers and receivers will be attached to each. One vessel, the No.18 Jinei Maru, will be in command of the survey. The two vessels will share the survey area. From among the large protrusions, which are thought to be several meters in diameter and in height, we will select the candidates for the Albacore. In the previous I-58 Ro-50 specific project, the MBES showed us submarines sitting on the seafloor at a depth of 200 meters. Since the depth this time is about the same, we will be able to see the shape of the elongated wreck in the data if Albacore was not shattered into pieces.

In the original plan for 2020, one of the support vessels was to be an Unmanned Surface Vehicle (USV). This idea was examined for the B-29 exploration in Tokyo Bay in 2021. However, we were not able to prepare an USV in time for this project, so we decided to use a regular vessel instead of an USV.

The ROV's position is measured in real time by the Super Short-Base Line (SSBL) acoustic positioning system attached to the No.18 Jinei Maru. A mosaic of the captured images will be used to reveal the entire topography of the seafloor. Note that the ROV we are going to deply is a compact one, is the same one used for the Ro-500 survey. The ROV survey will be extremely difficult due to its small size and concerns about strong tidal currents. Therefore, based on the results of this survey, we are planning to conduct another survey at the end of August 2022 using a larger ROV.

The major difference between this survey and the previous surveys is the use of two MBESs to increase survey efficiency and to find targets in a short time. We would like to emphasize that the first step in surveying and studying the seafloor is to make a map in detail.

Project timeline

Pledge Rewards

1,100 JPY tax included

Featured : Summary of Survey Results (PDF) / Thank You Message

We will send you a "Summary of Survey Results (PDF)" that summarizes the results of this survey. We will put a lot of effort into preparing this report, so please support us (the image is part of the cover of the "I-58" project). We will also include your name in the survey report if you wish.

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Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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64 supporters are supporting with this reward. （No quantity limit）

5,500 JPY tax included

Featured : Name in a reporting report in the ACADEMIST journal

Your name will appear in a research report to be contributed to the ACADEMIST journal.

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Name in a reporting report in the ACADEMIST journal / Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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85 supporters are supporting with this reward. （No quantity limit）

11,000 JPY tax included

Featured : Online special briefing

After the survey is completed, we will compile the results as soon as possible and hold an online lecture to report the results (the image shows the special debriefing session for the "I58" project). The archived video of the day will be made available exclusively to our supporters.

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Online special briefing / Name in a reporting report in the ACADEMIST journal / Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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57 supporters are supporting with this reward. （No quantity limit）

33,000 JPY tax included

Featured : Detailed Survey Report (PDF)

We will send you a detailed report of the entire survey. We are waiting for your support! (The above image is Ro-500 on the seafloor captured by MBES in 2018)

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Detailed Survey Report (PDF) / Online special briefing / Name in a reporting report in the ACADEMIST journal / Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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14 supporters are supporting with this reward. （No quantity limit）

55,000 JPY tax included

Featured : Survey Video Digest Version

We will send you a digest video of the survey, including underwater images.

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Survey Video Digest Version / Detailed Survey Report (PDF) / Online special briefing / Name in a reporting report in the ACADEMIST journal / Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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3 supporters are supporting with this reward. （No quantity limit）

110,000 JPY tax included

Featured : Detailed Survey Video Version

We will send you a detailed video of our findings. (The image above is the bathymetry data from the "I-58" project. taken by the MBES. The area where the Albacore is located is about the same depth, so if it has not broken up significantly, we will be able to obtain images like this.)

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Detailed Survey Video Version / Survey Video Digest Version / Detailed Survey Report (PDF) / Online special briefing / Name in a reporting report in the ACADEMIST journal / Name in the research report / Summary of Survey Results (PDF) / Thank You Message

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3 supporters are supporting with this reward. （No quantity limit）