Well, we’re just weeks away from setting out to uncharted waters yet again as we continue our explorations ‘in Bahama deep’. This next expedition will focus on Exuma Sound, where much like the Tongue of the Ocean on Andros, the Sound is a deep flanking margin dropping precipitously from the shallows to depths of several thousand feet. Such an amazingly eerie yet beautiful environment made more accessible by diving with rebreather technology. More on the excitement of this upcoming expedition soon enough…
I am writing today to chat a bit about expedition logistics. We’re using rebreathers, which are the absolute best tool for the job, allowing for deeper and longer forays into the mesophotic realm while taking advantage of reduced decompression obligations and the myriad of other benefits afforded by this technology. What gets complicated is expedition logistics. To dive rebreathers requires two things that are not often found in remote locations – industrial suppliers of gas (He and O2) and sofnolime – carbon dioxide absorbent.
Gasses can be sourced anywhere that supplies industrial gasses for other industries such as welding, airlines, medicine, etc. There is no easy solution to sofnolime, and it has to be shipped in or carried as luggage. At 44 pounds per container, it eats up a significant portion of your luggage allowance. So, shipping is the necessary evil, and the current agenda item on my list that is giving me a pit in my stomach the size of a watermelon. It’s just not easy, and reliability along the supply chain and shipping channel is a challenge. Ugghh.
Why do we need the stuff? Well, our exhalations contain an elevated fraction of carbon dioxide. Since we recycle each breath, this fraction would increase until we were physiologically overwhelmed and eventually had a negative response. So, we have to remove it. To do this we use a chemical based scrubber made principally of calcium hydroxide. It works, though has its disadvantages. Its heavy, its a consumable, and its expensive. if it gets wet, it’s highly caustic. Yet we take it underwater and it keeps us going. Advances are being made in carbon dioxide monitoring as well as in the absorption chemistry itself.
For the time being though, I have to get it where I’m going, and that isn’t proving to be very easy. More to follow…
http://ocean.nationalgeographic.com/ocean/explore/deep-fore-reef-in-toto/