Rain and Rainbows (28.13, 150.32)

I have been trying to make myself spend a good chunk of time outside each day. It is easy to get stuck in your routine, going from one air conditioned room to another, and unless we are pulling OBSes out of the water, you have to make a conscious effort to go outside. Depending on our heading and the time of day, I will either hangout on the port side bow or pull up a collapsible camping chair on the stern. This afternoon I got to enjoy the site of rain cloud veils dusting the distant (and no so distant) sea and watch rainbows dance across the sky as we chugged along. It was very peaceful.

Today was a big recovery day. At noon, we were all riding on the high of getting our second of the day, which would mean by the end of the day we would have collected three. This would be a big momentum boost for the science team. This momentum boost was soon stomped out, however, when the engineers pulled the tube out of the OBS that housed the data and battery pack only to find that it had water in it, smelled of rotten eggs and was completely chard on the inside. The engineers, knowing way in advance what the situation was, promptly dropped the whole thing over the edge of the boat, data and all.

The rest of us watched in jaw dropping horror until we got the explanation. The OBSes are powered with lithium batteries, 11 to be exact. When water leaks into the battery housing it can (and usually does) cause the battery to short circuit. If a spark is produced, the lithium can ignite. When the molten lithium comes in contact with seawater, it reacts exothermically (it gets REALLY hot) and produces hydrogen, which is very flammable, and other toxic corrosive gasses. This hot, fiery, toxic mess if very dangerous because it can not be put out with water and will just consume anything in its path. In this situation, they think the leak occurred a long time ago and we were just smelling the bits of gas that were left. But if a leak were to occur as the OBS was ascending, and that flammable reaction was peaking when the OBS was being lower onto the ship, it is a really dangerous situation. There was a situation a few years ago where that exact thing happened and when the engineers tried to pull out the data tube, a fire broke out that burned through that deck and the deck below it before the crew could put it out. Each lithium batter has the energy density of about half a sick of dynamite and when you have 11 batteries in close proximity to each other, the situation can quickly get out of control. Needless to say, if any signs of a lithium fire exist, it is much safer to just throw the whole thing back into the water, which is what our engineers did. Chalk one up for the ocean.

Losing that OBS data was a bummer because it was in a key location for the OBS array. That means we are relying on the two remaining G2 OBSes to provide the data that we just lost. And seeing how unreliable the G2s have been so far, it is not the kind of basket I want to be putting all of my eggs in. However at this point, we don't have any other options.

We made our third recovery of the day successfully around sunset. It was raining a little and the sun was setting on the port side of the boat and at the same time a giant rainbow filled the starboard side of the boat. The recovered OBS sat happily between the two. We took it as a good omen, hopefully for the rest of the trip, but at least for one more successful recovery.