The bosun’s chair

I’m thrilled to report that the deployments continue to go well. Having completed our 16th seamless deployment last night at 2000 local time (#17 is scheduled in 8 hours), we have become something of a crack team. I say “we”, but most credit undeniably goes to Mark and Ernie, the UCSD techs from the OBS lab, who actually put the OBSs together and do almost all the difficult and hard-to-remember-but-oh-so-essential steps of the preparation. If they miss any one of about 20 items on their long checklist, the instrument is doomed. Most of the remaining credit goes to the ship’s mates, who navigate us across hundreds of miles to within 10 metres of the location that we scientists dreamt up in the computer lab poring over satellite maps. They turn our prow into the wind, and then hold us steady for two hours, before executing a complex circular survey pattern that we also dreamt up in order to optimally locate the instrument once it has landed on the seafloor. Happily, the “complex circular survey pattern” ends up looking almost exactly like Pac-Man, so if we zoom out and look at our ship’s track for the last few hundreds of kilometres, it is studded with little Pac-People.

Sending another instrument off the side. From left to right: AB Eddie is manning the A-frame, Mark is keeping careful tabs on one tag line, Rachel holds the release rope, OTG Juliana signals to the winch operator to hold position, while Ernie pulls his tag line free.

Now that the deployments – with their coordinated efforts of 10 scientists and crew in an intricate system of machinery, maritime skill, rope-handling, and state-of-the-art remote sensing – have become commonplace, we are excited at the prospect of any novel ship activity. We had just such a diversion yesterday.

During a midnight deployment the day prior, a foot-long piece of plastic came loose from inside our A-frame’s pulley. In the event, it fell harmlessly into the ocean as a non-injurious reminder to keep hard hats on while deploying. However, the next day the Captain became concerned that there might be some remaining bolts in the pulley housing which could now rub away at the cable (very dangerous). So after yesterday’s morning deployment, he sent an AB up there to remove them.

AB Chris goes aloft.

This operation involved swinging the large crane over the back deck to raise one of the ABs in a “bosun’s chair” (an impossibly tiny seat with almost no supports to stop one falling out in front or back) to investigate. With four other hands on deck holding tag ropes to stabilise him, the intrepid AB Chris was lifted, legs dangling, about 20 feet into the air above the swaying back deck. Carefully avoiding the various dangling pulleys and other obstacles as the ship pitched and rolled, he gingerly started fishing wrenches out of his pockets and began to cautiously attack the tightly fixed bolts with one hand, while the other grasped at the A-frame for all the leverage he could muster. As if these aerial acrobatics weren’t impressive enough, when one particularly stiff bolt would not shift, Chris called down for more tools, which were either whisked up to him by means of a small bucket on another rope or simply knotted to the small rope by a series of half-hitches and hauled aloft.

As the last bolt came free we watching scientists loosed a cheer, thinking the deed done. Not so. At this point, Chris reached into another pocket and pulled out a tape measure. At the Chief Mate’s instructions, he started shouting down measurements. It turned out they were planning to actually fashion a new piece of plastic to replace the one that fell off, and wanted to get the dimensions just so. There may, therefore, be more overhead action tomorrow!

The whole experience left us even more awed at the range of skills, determination, and ingenuity of these maritime professionals. Without these folks, none of our scientific exploration would be possible.

Zach Eilon (on behalf of the Pacific ORCA team)

“Pass me a hammer!”




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