1996 – RV "Yokosuka" –– For most of 1995 and into 1996, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) employed the 4,439-ton Research Vessel "Yokosuka" to conduct the testing and workup of the 11,000 meter remotely-operated vehicle (ROV) "Kaikō", and the 6,500 meter ROV "Shinkai." It was not until February 1996, during "Yokosuka" cruise Y96-06, that "Kaikō" was ready for its first full depth dives. On this cruise, JAMSTEC established an area of the Challenger Deep (11°10’N to 11°30' N, by 141°50' E to 143°00' Ewhich later was recognized as containing three separate pools/basins en echelon, each with depths in excess of ) toward which JAMSTEC expeditions would concentrate their investigations for the next two decades. The Yokosuka employed a 151-beam SeaBeam 2112 12-kHz multibeam echosounder, allowing search swaths 12–15 km in width at depth. The depth accuracy of "Yokosuka" Seabeam was about 0.1% of water depth (i.e. ± for depth). The ship’s dual GPS systems attained geodetic positioning within double digit meter ( or better) accuracy.