Milwaukee Deep at (), virtually identical with the "Milwaukee"s reading. The existence of deep water to the Atlantic Ocean side of the Caribbean has been known for more than a century. One of the area's earliest soundings was obtained June 12, 1852 by Lt. S. P. Lee, U.S. Navy brig "Dolphin", with a reading of at (). Milwaukee Deep Milwaukee Deep, also known as The Milwaukee Depth, () is the deepest part of the Atlantic Ocean and is part of the Puerto Rico Trench. It has a maximum depth of at least . It is just north of the coast of Puerto
Challenger Deep multibeam echosounder technologies a depth uncertainty of ± (95% confidence level) on 9 degrees of freedom and a positional uncertainty of ± (2drms) remain and the location of the deepest depth recorded in the 2010 mapping conducted by the US Center for Coastal & Ocean Mapping/Joint Hydrographic Center (CCOM/JHC) aboard is at (). In November 2016 sonar mapping of the Challenger Deep area was conducted by the Royal Netherlands Institute for Sea Research (NIOZ)/GEOMAR Helmholtz Centre for Ocean Research Kiel aboard RV "Sonne". Using a Kongsberg Maritime EM 122 multibeam echosounder system coupled to positioning equipment that can determine latitude