"Takuyo" was the first Japanese ship to be equipped with the new narrowbeam SeaBeam multi-beam sonar echosounder, and was the first survey ship with multi-beam capability to survey the Challenger Deep. The system was so new that JHOD had to develop their own software for drawing bathymetric charts based on the SeaBeam digital data. In just three days, they tracked 500 miles of sounding lines, and covered about 140 km² of the Challenger Deep with multibeam ensonification. Under chief scientist Hideo Nishida, they used CTD temperature and salinity data from the top of the water column to correct depth measurements, and later conferred with Scripps Institution of Oceanography (including Fisher), and other GEBCO experts to confirm their depth correction methodology. They employed a combination of NAVSAT, LORAN-C and OMEGA systems for geodetic positioning with accuracy better than . The deepest location recorded was ± at ; for the first time documenting the eastern basin as the deepest of the three en echelon pools. In 1993, GEBCO recognized the ± report as the deepest depth of the world’s oceans. Technological advances such as improved multi-beam sonar would be the driving force in uncovering the mysteries of the Challenger Deep into the future.  1986 – RV "Thomas Washington" –– The Scripps research vessel "Thomas Washington" returned to the Challenger Deep in 1986 during the "Papatua Expedition, Leg 8", mounting one of the first commercial multi-beam echosounders capable of reaching into the deepest trenches, i.e. the 16-beam Seabeam “Classic”. This allowed chief scientist Yayanos an opportunity to transit the Challenger Deep with the most modern depth-sounding equipment available. During the pre-midnight hours of 21 April 1986, the multibeam echosounder produced a map of the Challenger Deep bottom with a swath of about 5–7 miles wide. The maximum depth recorded was (location of depth is not available). Yayanos noted: “The lasting impression from this cruise comes from the thoughts of the revolutionary things that Seabeam data can do for deep biology.”  1988 – RV "Moana Wave" –– On 22 August 1988, the U.S. Navy-owned 1,000-ton research vessel "Moana Wave" (AGOR-22), operated by the Hawaii Institute of Geophysics (HIG), University of Hawaii, under the direction of chief scientist Robert C. Thunell from the University of South Carolina, transited northwesterly across the central basin of the Challenger Deep, conducting a single-beam bathymetry track by their 3.5 kHz narrow (30-degs) beam echosounder with a Precision Depth Recorder.