The Cruel SeaNovember 17th, 2011 By Administrator Documentary Production, Field Production | No Comments
Wide Eye Productions just wrapped up a shoot in the South Pacific on board an oceanographic research vessel. The shoot documented a study of the Samoan Passage, a deep underwater canyon and “choke point” in the Pacific Ocean. University of Washington Oceanographer Matthew Alford contributed this report about the voyage. You can read more of his Samoan Passage blog, here.
On its first mission to the deep sea, soon after I wrote the last entry, one of the Crush Cam glass spheres imploded as it passed 3800 m. 380 atmospheres of pressure found an imperfection in the glass somewhere, and the sphere failed. The incredibly pressurized water instantly pushed inwards to compress the air to more than 1/380 of its volume – and the air recoiled to create a violent shock wave. Immediately, the implosion triggered the other sphere to implode. Up on the surface, all that we knew is that all of the data streams went dead. We feared the worst.
We anxiously waited over an hour while we hauled the instrument back up. A scene of destruction awaited us when we got the instrument back on board. Quite literally, two bombs went off right in the middle of all of our instruments. The CTD and nearly all of its sensors were badly damaged. Some were flooded with seawater as the shock wave forced pressure past the O-rings into the pressure cases. For some the impact of the wave was as if they had been dropped from a ten-story building or shot with a cannon – electronics components ejected from their circuit boards, cards shaken loose. One of our ADCP’s we thought was OK but the beams are still not functioning correctly. Really, a lot of damage was done and valuable ship time lost.
A big loss for us and the ship, who owns the CTD. We’ve spent the last day rebuilding – and thanks to a heroic effort by both of the marine technicians Ben and Trevor, we are back sampling again. Still, we have no real time data, only one salinity sensor, and only the weaker of our two ADCP’s, which will compromise our ability to measure the flows we want to study.
I’m quite humbled by the experience. We spend so much time at sea making these measurements that we sometimes forget the risk that each change to a system entails. I had gotten excited about adding Crush Cam to the CTD, and had not properly considered the damage that the spheres could do if they imploded. I knew that a sphere failure was a possibility – though remote – and should have known better. I will next time. For now, I’m pushing on with my tail between my legs and thanking the seas for not taking more – which they could have and surely will again.