The Five Deeps Expedition objective was to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019.[25] On 28 April 2019, explorer Victor Vescovo descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle DSV Limiting Factor (a Triton 36000/2 model submersible).[26][27] Between 28 April and 4 May 2019, the Limiting Factor completed four dives to the bottom of Challenger Deep. The fourth dive descended to the slightly less deep "Central Pool" of the Challenger Deep (crew: Patrick Lahey, Pilot; John Ramsay, Sub Designer). The Five Deeps Expedition estimated maximum depths of 10,927 m (35,850 ft) ±8 m (26 ft) and 10,928 m (35,853 ft) ±10.5 m (34 ft) at (11°22′09″N 142°35′20″E﻿ / ﻿11.3693°N 142.5889°E﻿ / 11.3693; 142.5889) by direct CTD pressure measurements and a survey of the operating area by the support ship, the Deep Submersible Support Vessel DSSV Pressure Drop, with a Kongsberg SIMRAD EM124 multibeam echosounder system.