World War II-era
During a test dive last week, the Hawai'i Undersea Research Laboratory (HURL) recovered the bronze bell from the I-400 - a World War II-era Imperial Japanese Navy mega-submarine, lost since 1946 when it was intentionally sunk by U.S. forces after its capture.
Longer than a football field at 400 feet, the I-400 was known as a "Sen-Toku" class submarine —the largest submarine ever built until the introduction of nuclear-powered subs in the 1960s.
The I-400 is now protected under the Sunken Military Craft Act and managed by the Department of the Navy. The recovery was led by veteran undersea explorer Terry Kerby, HURL operations director and chief submarine pilot. Kerby was joined by Scott Reed, Chris Kelley, and Max Cremer (all with HURL) on the dive.
The team used both of HURL's human-occupied submersibles, Pisces IV and Pisces V.
Teamwork between the two subs was instrumental in recovering the bell. Since 1992, HURL has used its submersibles to search for historic wreck sites and other submerged cultural resources as part of the National Oceanic and Atmospheric Administration's (NOAA) maritime heritage research effort. Heritage properties like historic wreck sites are non-renewable resources possessing unique information about the past.
This recovery effort was possible because of a collaboration between the University of Hawai'i School of Ocean and Earth Science and Technology, California State University-Chico (CSU-C), Naval History and Heritage Command and the USS Bowfin Submarine Museum.