NOAA Ship Okeanos Explorer departed Guam at approximately 10:00 am this morning to commence the 2016 Deepwater Exploration of the Marianas expedition. Mapping operations were started once the ship was out of the harbor and continued en route to Fina Nagu Caldera A. At Fina Nagu, CTD rosette operations were conducted to collect water chemistry data to look for signs of active hydrothermal venting. Unfortunately, an electrical failure occurred during CTD operations so these were aborted, and mapping operations continued overnight. Onboard personnel spent the day getting familiar with ship systems and operations and preparing for the first remotely operated vehicle dive. Tomorrow, the ship will transition to operating on Fiji time (GMT +12) instead of ChST (GMT +10) to enable the participation of scientists and students across the U.S. mainland, and ensure as much participation as possible.