Friday, January 13, 2006
Scuba Lesson #1
I had my first scuba lesson this evening. When I showed up, they fitted me for a Buoyancy Compensator Device (BCD), a jacket/vest which holds the air tank and which has inflatable chambers to control buoyancy. They also gave me a regulator, weight belt, and air tank.
Then we met in a classroom. There are eight people in the class. We all introduced ourselves. The instructor gave a short PowerPoint-style presentation, then we went over the "Knowledge Quest" (a short quiz) for chapter 1 of the textbook. Then we went to the pool.
The instructor demonstrated how to assemble the scuba equipment (attach the air tank to the BCD, connect the regulator to the tank, connect a low-pressure hose to the BCD, turn on the air flow). We got into the pool, which was pleasantly warm, then donned all the gear. The instructor went over some hand signals and basic emergency procedures. Then it was time to start breathing underwater.
The first breath was very intimidating. I half expected to get a mouthful of water as I inhaled from the mouthpiece, but everything worked just as it should. Breathing from a regulator feels just like breathing through a snorkel, except that when you exhale, you get a lot of bubbles in front of your face. We all descended, crouching on our knees or sitting on the bottom (four-and-a-half feet deep), and just sat there breathing for a while to get used to it.
The first set of skills practiced taught us what to do if the regulator comes out of one's mouth. One must first find the regulator, which is not easy with the mask blocking one's peripheral vision. There are two basic methods: the sweep method, where one moves the right arm in a circular motion from the back, hoping to end up with the regulator hose caught in the arm; and the reach method, where one reaches back to the top of the tank, and grabs the topmost hose coming out of the tank. After getting the regulator, one must clear the water out of it before inhaling, which you do either by blowing the water out or by using the purge button. We practiced and demonstrated these methods.
Next was learning to clear the mask: that is, to get water out of it if it becomes full. This is easy: just exhale from the nose while slightly pulling the bottom of the mask away from the face.
Finally, we did a little swimming. The dive master noted that AMC is playing a bunch of James Bond movies this week, and recommended that we watch Thunderball to see some really good examples of divers swimming (Sean Connery's scuba double is particularly good, he said). The group was happy about that assignment.
After that, we had about fifteen minutes to just "play," practicing the skills. The only thing I really had trouble with was the swimming—I just couldn't move very well. I'll get more practice in the coming days.
Finally, we got out of the pool, disassembled and rinsed everything, and then went home. We'll meet again tomorrow.
A common problem with new divers is panic. The dive master noted that it is not uncommon for somebody to freak out during lesson #1. I didn't panic, but I'll admit there were a couple of times when I had an irrational desire to ascend to the surface as quickly as possible, as if I could sense that the regulator was about to stop working. There is something about breathing through a little tube in a strange environment that is unnerving. I kept my cool, but I can certainly understand how somebody could lose it, especially if some real danger were to present itself.
Two lessons to go . . .
My teacher spent one classroom session doing the physics of a rocketing air tank. Apparently, if the valve of the tank shears off (because you dropped it, dumbass) the tank will go from 0 to 60 mph in about 100 meters.
We also did some significant snorkeling in the class (again, probably to extend it to a semester) so I got a lot of opportunities to inhale a mouthfull of water. After snorkeling for a week, switching to a scuba tank was a breeze. (I think the teacher did this to ensure nobody panicked).
One of my favorite classes was 'tag'. Tanks were set at the bottom of the pool and each person dove down and started to breath. Once everyone was down and breathing, the teacher dove in and 'tagged' on of the students. That meant you dropped the regulator and swam to someone else on a tank and tagged them. Since there was always one more person than air tank, everyone got good at (a) making sure they could clear a regulator and (b) ensure you had enough air in case you got tagged.
A couple of weeks ago, I saw an episode of Mythbusters were they tested whether shooting a tank will make it explode, as at the end of "Jaws." The answer is no, but the tank did fly around a lot due to the pressure ejected through the bullethole. (But, of course, they wanted to see an explosion, so in the end they attached some C4 to the tank.)
AndI laughed at your matching column on my blog.
Have you tried LinkedIn? Good for tech sector jobs.
LinkedIn seems to be good only for people with whom I've worked with before. Not so good for expanding my career.