September 29, 1998. If you are going to be on this ship, you better be prepared to work strange hours. The research and data gathering does not stop when the sun goes down. It continues 24 hours a day. Remember that it takes 35 hours for the ship to tow the DSL 120 from one end of the ridge to the other. So there must always be people in the control van making sure that the vehicle stays on course, avoids hitting something, and that the side-scan sonars continue to provide data.
There was a lot of anticipation when the watch assignments were posted. Who would participate in two four-hour watches per day instead of one? And who would be assigned the deadliest watchesthe ones that take place from midnight to 4:00 a.m., and from 4:00 to 8:00 a.m.? These are the sleepy people who are now trying to adjust their body clocks to strange hours.
All watches take place in the control van, the nerve center where all underwater vehicles are controlled. In the lingo of the control van, the underwater vehicle is called "the fish." Inside the van, one cannot help but be dazzled at the sight of all those bright computer monitors flashing bright images and numbers. These bright colors lend the darkened room a strange, futuristic glow.
My job is to watch the brightest, most colorful computer screen of allthe one that displays the sonar images of the sea floor. It took me a while to translate all the colors and graphs and numbers flashing in front of me into something meaningful. There was one band of colors on the right side of the screen that showed the intensity of the sound waves reflecting back from the surface. I dont have to worry about that one. The middle and most mesmerizing band of colors showed the bathymetry of the ocean bottom. A bathymetric map is a relief map of the ocean floor. Other than adjusting the depth of the fish. I dont have to pay much attention to that either.
I do have to pay attention to band of colors on the right. This band displays the distance between the DSL 120 and the bottom of the ocean. This measurement is called the altitude. Normally the goal is to maintain an altitude in the neighborhood of 100 meters. I help monitor whether the fish is getting too close or too far from the bottom and correct any faulty altitude readings. And, of course, I attend to other distressing details such as making sure that we are successfully recording data from the sonar and letting the right people know if the screen suddenly goes blank. Four hours is a long time to watch a computer screen, but I dont need that type of excitement.
There are three other people per watch. The navigator and flyer keep the DSL 120 on the right course. The flyer is in charge of raising and lowering the fish so that it can follow the contours of the ridge and avoid crashing into things. The flyer must use some discretion, however. Whenever the fish is reeled in, the cable pulls the nose up so that the vehicle is no longer parallel to the ocean floor. As a result, the sonar equipment is no longer pointed to the ocean floor. The result is poorer images. Changing altitude also causes the fish to bob up and down, making the sonar picture even blurrier. The flyer uses a map to anticipate changes in the depth of the sea floor so that he or she can raise or lower the fish only when necessary.
Finally there is the watch leader. He or she looks at the big picture, plots the position of the DSL every 15 minutes, keeps each person on the watch informed about what the others are doing, and, of course, keeps everybody awake.