Last Friday was one of the most intensive days so far. All crew members were awake since the early hours of the morning awaiting the approach to the first deployment site located at 1.286 N -17.899 E.
An ocean bottom magnetotelluric instrument (OBMT) was deployed first. This was followed by a series of acoustic tests made to establish communication with the ocean bottom devices. Unlike on land, sound waves are a more convenient means of communication for devices. These tests took several hours to perform, mainly because of the long time it takes to lower down the acoustic transducers (acoustic transmitters and receivers) into the ocean to a depth of 3,500 meters. The cable is lowered slowly at a rate of 1m/second, thus taking nearly 1 hour each way.
Following these tests an ocean bottom seismometer was then released into the ocean, but only after the ship moved about 1 km away from the previous site in order to keep the instruments a safe distance from each other.
We are Honourable Shellbacks
As we sail farther south to our next deployment site (a transit of 6 hours) we happen to cross the equator. The ‘Crossing the line’ is usually celebrated in various different ways by the naval community. We did not do any crazy ceremony such as those hinted on Wikipedia , however, some of us were just happy to cross the line and accepted the title of Honourable Shellbacks.