I occasionally take some flak on some of the Internet SCUBA diving boards for the way I dive. It mostly comes from technical divers, but occasionally from some instructors. The gist of their criticism is that I should always "plan my dive" and "dive my plan." This is considered good diving technique by most agencies, and is very appropriate for most kinds of divers. However, it just doesn't work for me most of the time. Although some seem to suggest there is one right way to dive, I find it is highly dependent on what the purpose of your diving is.
Technical divers who do wrecks or caves definitely need to plan their dives. It is often critical if you plan to penetrate a wreck, or go deep into a cave. Planning for your needs in terms of air, in terms of time and in terms of special equipment can make the difference between coming back alive and over extending your stay... permanently. Of course technical divers often have a very significant advantage... they know where they are going! A wreck generally rests at a known location and depth, making calculations for bottom time and decompression (if necessary) fairly easy.
Videographers like myself have a different goal when they dive... to film marine life. My fellow Oak Parker, Ernest Hemingway, once referred to "A Movable Feast." This might be an appropriate phrase to use for my kind of diving. A mobile critter like an angel shark may be encountered... or not... at almost any point in my dive profile. Most of the time when I drop down at a dive site, I have no idea what I will find there. It is hard to plan your dive when Mother Nature is in control.
One example from my dives last week aboard the King Neptune illustrates this well. We anchored outside the reef at Torqua Springs, site of the old spring that provided early Avalon with much of its fresh water. There is a geologically interesting shallow boulder reef, but I usually drop down to at least 100 feet and slowly work my way up to the reef. Of course that's a loose dive "plan" in itself.
This time I dropped down to about 100 feet. As I started working my way upslope, my eye caught something swimming behind me. I turned to discover a Pacific electric or torpedo ray moving about 10 feet off the bottom. I rarely encounter these rays when they are swimming. I usually find them resting on the bottom, which does not make them a very interesting subject to film. It's kind of like filming a sleeping baby (or babe!). There was no question I would follow this one and take as much footage as it would allow. I expected a few minutes with it at most, but it kept swimming for 20 minutes with me in hot pursuit, camera rolling!
Keep in mind that the electric ray was behind me at 100 feet. My dive "plan" quickly changed so I could follow the ray. It took me even deeper, down to 115 feet, and kept me at depth for more than enough time to place me in a decompression or deco dive situation. In fact my computer said I would have to do a 15 minute deco stop in shallower water to release all the nitrogen I had absorbed. I dive with a large capacity 120 cu. ft. tank and carry my new, larger pony bottle so this would not be a problem. I slowly swam up to the shallow reef and spent a conservative 20 min at 10-15 feet to eliminate the nitrogen. No problem.
While filming a moving subject, I follow it looking through the tiny viewfinder in my camcorder. This gives me a very narrow view of the environment in front of me. In fact, while filming a swimming C-O sole, I ran into a rock on the bottom which stopped me cold (but fortunately didn't damage the underwater housing)! The electric ray presents a different problem. If I get too close or irritate it, this fish has the ability to deliver a potentially disabling shock! Several times the ray turned around to look at me and I had to quickly back pedal, or more accurately back fin. This could have turned into a rather shocking experience.
I thought back to another dive a few years ago in our Casino Point dive park. I had made a dive "plan" to go no deeper than 40 ft. and decided not to strap my pony bottle onto my main tank for backup. Of course as a videographer, dive "plans" are meant to be broken at the first sign of something interesting. At 40 ft. I saw a large bat ray swimming in front of me and followed it down to over 70 ft. At that point my tank valve clogged and no air came out of my tank... period. Thanks to excellent training, large lungs and lots of experience, I was able to make a controlled emergency surface ascent (CESA) and survive.
That dive reinforced in me the most important part of the dive planning necessary for my type of diving... proper equipment. From that point on I've always carried redundant systems to ensure a margin of safety since I dive mostly solo. My primary tank is equipped with a regulator that has three second stages on it. I always carry my pony bottle and its regulator regardless of where I think I'm diving. After a computer failure on a deco dive a month ago, I'm considering a backup computer as well.
So my dive "plan" usually consists of being ready to go anywhere that an electric ray, soupfin shark or mating squid may take me. I rarely know for sure what I will encounter, but I make sure my equipment can support me wherever "it" takes me (well at least down to a maximum depth of 180 ft.). You can't control Mother Nature, but you can ensure that you are ready for anything a dive might bring you. After all, I was a Boy Scout back in ancient times and still believe in being prepared. And that's my plan.
© 2006 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," or "Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!
The Pacific electric ray that became my dive "plan" at Torqua Springs.
This document maintained by
Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia