2009 – RV "Kilo Moana" –– In May/June 2009 the US Navy-owned 3,064-ton twin-hulled research vessel "Kilo Moana" (T-AGOR 26) was sent to the Challenger Deep area to conduct research. "Kilo Moana" is civilian-manned and operated by SOEST. It is equipped with two multibeam echosounders with sub-bottom profiler add-ons (the 191-beam 12 kHz Kongsberg Simrad EM120 with SBP-1200, capable of accuracies of 0.2%-0.5% of water depth across the entire swath), gravimeter, and magnetometer. The EM-120 uses 1 by 1 degree sonar-emissions at the sea surface. Each 1 degree beam width sonar ping expands to cover a circular area about in diameter at depth. Whilst mapping the Challenger Deep the sonar equipment indicated a maximum depth of at an undisclosed position. Navigation equipment includes the Applanix POS MV320 V4, rated at accuracies of ½-to-2 meters. RV "Kilo Moana" was also used as the support ship of the hybrid remotely operated underwater vehicle (HROV) "Nereus" that dove three times to the Challenger Deep bottom during the May/June 2009 cruise and did not confirm the sonar established maximum depth by its support ship.