martini's law.

Weeks and weeks have gone by since I've been here at the blogger. Ever so busy weeks and weeks.

Last week concluded the first 8-week module (of 2 each semester) of the MDT program, which is apparently the hardest. Despite that I'd taken only 2 of the 5 offered (the others being dive and equipment classes, which I'll take next semester, upon passing the swim eval), I was stressed about the exams. My classes last module were Fundamental Practices of Diving (read dive physics/ physiology) and Rigging (recall knot-tying exercises of earlier blog). Rigging required a written final exam, and a demonstration of skills for the lab portion. For the lab final, each student was required to tie 10 knots, chosen at random from a list of 20, blindfolded; reeve a multi-part block (basically guiding a rope through a system of pulleys); and complete 3 different types of splices in natural fiber rope, and one splice in wire rope. The knots were not as difficult as I'd thought, and the rest of the final was easy. I passed with an excellent grade.

Fundamental Practices of Diving has been, by far, the most intense class I've taken. The material is dense and complicated, and requires quick and frequent manipulation of memorized information, such as using dive tables, and calculating partial pressures of breathing gases at depth. I'd studied most of the material before, for my divemaster cert., but the MDT instructor instilled a healthy fear of failing into each and every one of us, and in my case, it inspired me to keep up. The final was scary, but also a good challenge, and sort of fun in that way. I also passed this course with an excellent grade, which has allowed me to continue on to more advanced classes.

The new module began this week, with the following classes: Intro to Marine Welding, Hyperbaric Chamber Operations, and Hydraulics I. Monday was the first day of welding (and the intro class is only just welding, topside, dry), and me being the only girl, and never having held a torch in my entire life, having only the vaguest sense of what the hell I'm supposed to be doing, the instructor felt it necessary to call me up first every damn time, to demonstrate every damn thing, in front of all the stinky boys. I was a bit put out at first, but the stinky boys (who are really not so bad, most of the time) were helpful or humble, depending on their own [in]experience with welding. Of course, the obvious flashdance comparison came up in my mind, and since Jennifer Beals is gorgeous, I'll continue to allow that little fantasy (and that catchy tune... What a feeling!/Bein's believing/ I can have it all/ Now I'm dancin' for my life!/Take your passion/ and make it happen!) to run and play in my mind, as much as it wants.

Another class, Hyperbaric Chamber Operations. For whatever reason, this class was one that caught my eye from the first. Quick background: when using scuba, a diver is breathing air, which consists of 21% oxygen, and 79% nitrogen (a bit of this and that also mixed in, but essentially what we breathe in the atmosphere is contained in scuba tanks to be breathed at depth). Nitrogen is an inert gas, and plays no real role in metabolic function. At the surface, it's harmless, and generally speaking, it's also harmless at depth, so long as a diver, upon ascending, allows the nitrogen to be released properly out of the system by ascending slowly, and by taking short breaks along the way (ie decompressing). If a diver ascends too quickly, the nitrogen in a diver's system can be released too quickly, forming bubbles that can increase in size as pressure on the body decreases closer to the surface, causing any number of problems, depending upon where in the system the bubble is located. As diving depth and time increases, so does the amount of nitrogen in her system, and the longer she'll need to decompress. Decompression can last for several hours.

A hyperbaric chamber simulates pressure and, in diving, can be used in 2 different ways: first, as a method to treat illness brought about by diving, usually related to gas bubbles in the system; second, as a way to decompress out of the water, and this is common practice in commercial diving. The chambers owned by the MDT program aren't huge, each measures around 9 feet long, with a 5-foot diameter, and looks like a big metal tube, with a bunch of gauges and meters and pipes and hoses coming out of one side. When going for a *dive, the divers get in, seal the hatches, and enough air is introduced into that air-tight space to simulate the same pressure one would experience at any depth between 0 and 165 feet of sea water. A few of us went down to 30 feet last week. Today we went to 90.

A funny thing happens when a diver is at a significant depth, like 90 feet. For whatever reason, nitrogen at depth can have the effect of making a diver feel a bit tipsy, like after having a few drinks. The effect is called nitrogen narcosis, or getting narc'd, or martini's law. This has happened to me one time, and I was deep: 160 feet. I felt silly and happy and wonderful. It's really an amazingly good feeling, except that you're at depth, with impared judgement, but you don't really think of that, because it feels so damn good, and everything looks really beautiful and fascinating. Today, sitting in that cold metal chamber, we got narc'd at 90 feet. Can't say I've ever felt so good in class.