April 16 - May 10, 2021 The NOAA Office of Ocean Exploration and Research (OER) will begin the 2021 operations aboard NOAA Ship Okeanos Explorer with a 25-day expedition, April 16 - May 10, to assess the functionality and ensure readiness of mapping-related equipment, including a new state-of-the-art EM 304 multibeam sonar transducer. The 2021 EM 304 Sea Acceptance Testing and Mapping Shakedown will be split into two legs. The first leg will be a sea acceptance tests (SAT) for the EM 304 transducer (April 16 - April 23), and the second leg will continue with annual testing of all mapping equipment followed by exploratory mapping operations on the Blake Plateau as time allows (April 25 - May 10). The expedition will begin in Key West, Florida, and end in Port Canaveral, Florida.