Last night, we deployed a tow camera to take photos of the sea floor to look for any evidence of oil that may have settled there, and for hydrocarbon seeps. Ken Feldman, a contractor working for Woods Hole Oceanographic Institution, is in charge of the tow camera operations on this expedition. After we brought it back to the surface, he talked a little bit about the tow camera and how it works.
The camera is in a pressurized housing…It triggers a flash every time it takes a picture, which is important because there is very little light at the depths where we’re operating. We program the camera to ‘sleep’ for the 30-40 minutes while we lower it, using a winch, to the sea floor. Once the camera ‘wakes up’ on the bottom, we set it to take a picture every ten seconds. It has two altimeters – one that looks down, so we can see how far we are off the bottom, and a forward-looking one, so we can detect any obstacles in front of the camera and avoid running into them. We try to keep the camera about two meters off the bottom. During this process, we keep the ship moving forward slowly (at speeds of less than a knot) and take in or let out cable to keep it at the proper height above the sea floor. I’ve heard it compared it to flying a blimp through the Grand Canyon and lowering a refrigerator on a rope and trying to keep it five feet off the ground.
You see a lot of interesting stuff in the pictures. On this trip, we’ve seen fish, crabs, shrimp and other animals. In the six years I’ve been doing this work, I’ve seen an octopus attacking the arm of an ROV, and some amazing geological features in some volcanically active areas, among other things. It’s an interesting world down there.