Editing Challenger Deep (section)

===1962 – RV ''Spencer F. Baird''===
The ''Proa Expedition, Leg 2'', returned Fisher to the Challenger Deep on 12–13 April 1962 aboard the [[Scripps Institution of Oceanography|Scripps]] research vessel ''Spencer F. Baird'' (formerly the steel-hulled US Army large tug ''LT-581'') and employed a Precision Depth Recorder (PDR) to verify the extreme depths previously reported. They recorded a maximum depth of {{convert|10915|m|}} (location not available).<ref>Fisher, Trenches, The Earth Beneath the Sea, Table I, p. 418 Table 1</ref> Additionally, at location "H-4" in the Challenger Deep, the expedition cast three taut-wire soundings: on 12 April, the first cast was to 5,078 fathoms (corrected for wire angle) {{convert|9287|m|ft}} at {{Coord|11|23|N|142|19.5|E}} in the central basin (Up until 1965, US research vessels recorded soundings in fathoms). The second cast, also on 12 April, was to 5,000<sup>+</sup> fathoms at {{Coord|11|20.5|N|142|22.5|E}} in the central basin. On 13 April, the final cast recorded 5,297 fathoms (corrected for wire angle) {{convert|9687|m|ft}} at {{Coord|11|17.5|N|142|11|E}} (the western basin).<ref>"Physical And Chemical Data, PROA Expedition 12 April – 6 July 1962", SIO 66-16, p. 3</ref> They were chased off by a hurricane after only two days on-site. Once again, Fisher entirely missed the eastern basin of the Challenger Deep, which later proved to contain the deepest depths.