Editing Challenger Deep (section)

===1986 – RV ''Thomas Washington''===
The Scripps research vessel ''Thomas Washington''{{'s}} 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 [[Swathe|swath]] of about 5–7 miles wide. The maximum depth recorded was {{convert|10804|m|ft}} (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."<ref>Yayanos, A. A., R/V Thomas Washington KGWU, Weekly Report, Papatua Expedition Leg 8, 212218Z April 1986</ref>