Teacher Logbook - NOAA Ship Ron Brown

The elevator, loaded with experiments, is deployed from the ship prior to dive R629. The instruments (experiments) were placed at Cloud vent on the '98 lava flow. Cloud vent is in the background, surrounded by scientific experiments and gear. The box in the center is a biology box (bio-box), which was used to transport the arrays to the elevator after their one-week deployment. The colorful rectangular object on the right is a larval settlement array. The tube lying in front of the bio-box is a larval trap. Two larval settlement arrays and four larval traps remain at Cloud for a one-year experiment

Jeff Goodrich's Sealog:
Axial Volcano - 1998 lava flow
July 27, 2001

Deploying and recovering instruments from the ocean floor is no easy task. It takes many skilled people and a lot of ingenuity. The science party brought along two PMEL engineers, Chris Meinig and Nick Delich, who perform a multitude of tasks while on board and in the office (where they design and test the instruments needed for research cruises). The engineers are assisted by Bruce Cowden, the chief bosun, and the ROPOS crew while preparing the instruments for deployment and recovery. Their biggest challenge thus far was to overload an aluminum-rail elevator three times its maximum load, deploy it, sink it, unload it, load it back up, release it from the bottom, and recover it all during daylight hours. It's nearly impossible to see and recover even brightly colored objects at night.

Working with biological oceanographer Anna Metaxas, their first task involved reinforcing the aluminum-rail elevator by wrapping it in a nylon sling to make the maximum load-carrying capacity higher. Next, a spreadsheet was designed to calculate the weight of the instruments plus the elevator in air and under water. This is tricky because there's no easy conversion between the two. Different materials weigh different percents of their air weight, once in water. With the total weight calculated for deployment, they then calculated the total weight during recovery for the instruments that were coming up from the seafloor.

Next, the correct buoyancy is calculated for the given weight, and a number of large yellow floats are attached to the elevator to raise it from the seafloor. With buoyancy added, they must then calculate how much weight must be added to sink the elevator to get it down to the bottom during deployment. A weighted railroad-car wheel is attached to the underside as an anchor for sinking. To raise the elevator off the bottom, an acoustic release is added to free it from the railroad wheel anchor. The instruments in the elevator need to be secure for the ride up or down but also be accessible by the limited dexterity of ROPOS. Sound complicated? It is. That's why we have engineers.

With the elevator finally ready, they deployed it this morning with no problems. All the new experiments/instruments were deployed on the bottom, where they will spend the next year. Experiments that were finished were placed in the elevator. Dive R629 was a success, at least we hope so, as the elevator is still on its way to the surface. When the experiments are safely on board, we will all breathe a sigh of relief.