Scuba 6/14/21

Recollections by Richard Bleil

For a time, scuba diving was all the rage.  I’ve always wanted to learn to scuba dive (“scuba” is actually an acronym for “self-contained underwater breathing apparatus”), and in the mid ‘90’s I finally took lessons and obtained my open-water dive license.  This means that I can dive as long as there is a clear path above me to the surface.  There are special licenses to allow you to go into wrecks and caves. 

The training was brutal.  I was teaching at a medical arts college at the time, associated with a major medical center.  Our dive lessons were at the private heated pool of an anesthesiologist that worked there.  So difficult biting the bubbles. 

The license was from an organization called PADI, the Professional Association of Dive Instructors.  They’re still around today, and presumably the license never expires.  None the less, it’s been so long since I’ve been diving that I would take refresher lessons if I were to resume the hobby.  The photo for the license was taken immediately after the check-out dive, so my hair was rather wild and unruly.  I still carry the license today, and on occasion, if somebody asks me for a photo ID without specifying the type I will hand them the scuba license.  It never fails to catch them off guard.  Usually they timidly reply, “do you have a driver’s license?”, but I have had somebody accept it once. 

I’ve only been on one dive, which is very sad.  I did have a dive planned in Florida, but washing dishes the night before, I had a glass break on me while my hand was in it, cutting me severely enough that I felt I needed to go to the emergency room.  Driving to the emergency room with my hand wrapped in a towel, and being that I’m a man, I had two thoughts cross my mind.  The first was that, since my mother had given me the towel and it had flowers, I hoped it was masculine enough to be seen in public.  Then I thought, wait, it’s soaked in blood.  How much more masculine can you get?  Several stitches later, the doctor told me to keep it dry for longer than the dive trip was supposed to last, so, that was the end of that dream.

I did go wreck diving in Michigan.  Michigan has some of the strictest dive laws (as I understand it) in the country.  The wrecks in the great lakes are much like dive museums.  There are years of prison terms and tens of thousands of dollars in fines if you bring up any souvenirs with you.  As such, there are wrecks (I’m told since I cannot dive into the ship with an open dive license) that still have silverware on the tables.  The wreck I visited as an old cargo ship.  It was torn in two in a storm.  It’s amazing how sometimes there are reminders of just how powerful nature can be.  There was a bolt on the deck with a diameter that had to have been ten inches across that had been sheared off entirely. 

There are three types of dive suits.  For warm water, there are “dive skins”.  These are basically very thin material designed to protect the diver from stings like what from coral or jelly fish.  Of course, they’re thin material so there’s no protection against lager bites.  You really can only wear these in very warm water as it has no real insulation. 

One of the most interesting dive suits is the most common, called the “wet suit”.  These fit tightly and are like a thin layer of sponge.  These are designed, as the name implies, to absorb water.  The concept is that the water against the skin will warm up, and the wet suit will hold that layer of water near your skin so it does not flow.  Once warm, this water will keep the diver warm, and a “temperature gradient” will be created between the suit closest to your skin which is near your temperature and the suit closest to the water which will be the temperature of the water.  Because water is a relatively good insulator, this is an effective dive suit down to, oh, maybe 40 degrees Fahrenheit, water that is about the temperature of refrigerated water.

A “dry suit” is just that.  It’s vulcanized rubber with a liner designed to go over whatever you’re wearing.  This is effective down to the freezing point of water.  In spy movies, when they remove the dive suit and reveal a tuxedo underneath, they are wearing a dry suit.  I should try that, scuba diving in a tux.

We all know, by the way, that water expands on freezing.  This is why ice floats; the density of the ice is higher lower than the density of water.  In fact, water is the only chemical known to science that expands on freezing (although there is one metal in its elemental form that also does so).  What few people know is that, just like any other liquid, as water cools it still gets denser.  Water is most dense at about 39 degrees Fahrenheit (4 degrees Celsius).  This gives rise to what is called an “isotherm”.  There’s often a plane of water where there is a sudden and noticeable drop in temperature.  This is a layer of water that is more or less a constant 39 degrees to the bottom, the densest water in the body of water.

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