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  • Karl Huggins' Journey to the Edge (the development of the world’s first commercially successful electronic dive computer)

    © 2011 Steven M. Barsky. All rights reserved.

    There are many famous people in diving who have developed marvelous inventions that have changed the way we dive. However, unless you are interested in diving history, you probably haven’t heard of most of them, except perhaps for Jacques Cousteau
    , who is widely reported as the inventor of the AquaLung®, but that’s another story….

    The Edge Dive Computer was the first commercially successful dive computer that was based on microprocessor technology. It used a decompression algorithm, rather than tables.

    For most divers today, one person who helped change the way we dive is a guy by the name of Karl Huggins, who saw the future of decompression theory and helped develop the Edge, the first modern commercially successful microprocessor-based electronic dive computer. Without the development of the Edge, we might all still be using paper based decompression tables to compute our dive times. Huggins today runs the University of Southern California’s Catalina Hyperbaric Chamber on Catalina Island, a long way from his home state of Michigan. He first became captivated with the underwater world watching the Cousteau specials on television and seeing the undulating beauty of a Red Sea nudibranch, the “Spanish Dancer” in an eighth grade science course.

    Huggins Learns to Dive
    Karl remembers receiving a pair of Jet Fins in junior high and being amazed at their speed and power, when he unexpectedly ran into the side of the pool. He loved the water and took courses in lifeguarding. In high school, he, along with other lifeguards, found a full-face mask and compressor and tried it out cleaning the bottom of the pool, but as he puts it, “There weren’t many opportunities in the area for a person to learn to dive at that time.”

    But, it was his involvement in the attempted resuscitation of a man who had a massive coronary in Karl’s high school pool that left an indelible mark on Karl’s psyche. Although Karl and the others who made the rescue did their best, the man could not be revived. His memories of this rescue and the concern for others instilled into him by his parents were markers that changed his life.

    For college, Karl enrolled in the University of Michigan in biological oceanography and took courses in aquatic leadership. Following an introductory orientation to the use of scuba, Karl enrolled in a scuba course in 1976 under the tutelage of Dr. Lee Somers, a legendary educator in the diving field. He went on to take further courses in underwater technology and chamber operations from Somers, and began to assist with scuba classes.


    While taking the underwater technology course, Karl got interested in the concept of decompression tables and how they were calculated. Encouraged by Somers, who gave him several papers on decompression theory by Dr. Bruce Bassett, a diving physiologist, Karl spent his afternoons at the local bookstore, programming their HP67 calculator to run decompression tables.

    As Karl admits, “I used the display calculator in the store, because I couldn’t afford to buy my own $700.00 calculator at that time. Using Bassett’s ideas and the U.S. Navy diving medical officer’s handbook, I just started playing with decompression calculations.”

    When his father got a new calculator he gave Karl his HP55 calculator which could be programmed to do dive tables. Although it was less powerful, and had no print-out capability, it did the job.

    In 1979, Karl took a trip with the other scuba class assistants and instructors from the University of Michigan to San Salvador, in the Bahamas. While on this trip, he met diving instructor Dee Scarr, who introduced him to the concept of multi-level diving, similar to a practice widely used in the commercial diving field known as “repet-ups.”

    At that time, divers were trained to perform calculations for “square profile” dives, where, no matter what your profile was, you computed your whole dive as if it took place at the deepest depth you explored. This procedure “penalized” the diver for the maximum depth he reached. Scarr and other people, however, were using paper-based U.S. Navy decompression tables to calculate and perform extended dives by working their way “up” through the no-decompression tables to progressively shallower depths.

    Just as a modern dive computer will allow you to make a multi-level dive for a longer time than what you could spend at your maximum depth, a similar profile could be calculated using the tables. With their method, you could extend your bottom time and calculate what’s known as a “repetitive group” while theoretically taking into account the additional nitrogen you absorbed as you stopped at different depths as you worked your way to the surface.

    The concept of a multi-level dive intrigued Karl, but there were things that bothered him about it. Specifically, the Navy tables were based on six different theoretical tissue groups (compartments), while the calculations for repetitive groups were only based on one compartment. (For simplicity, you can think of a compartment like a particular type of body tissue, although it does not represent any specific tissue in the body).

    When Karl returned to the states, he began running various dive profiles on his HP calculator to see what was happening mathematically in the other five compartments of the US Navy model. Based on his calculations, he found that in some cases using the multi-level dive procedure, you violated the Navy model, which could place you at higher risk for decompression sickness.

    In his reading on decompression theory, Karl was given the work of Dr. Merrill Spencer, who had used a “Doppler meter” to detect bubbles in the bloodstream of divers, even those without decompression sickness. Karl began working on various ideas on how to put together a no-decompression table that would not cause the violations he found in the Navy tables when they were used for multi-level diving. Eventually, he developed a table with repetitive group designators that represented all six compartments.

    Based upon Spencer’s Doppler limits and the work of Bassett, Karl developed a set of tables that was published by the University of Michigan’s Sea Grant program. The publication was entitled “New No-Decompression Tables Based on No-Decompression Limited Determined by Doppler Ultrasonic Bubble Detection.” (You can still download the paper off the Internet.) After graduating cum laude with his bachelor’s degree in 1979, Karl took a year off before starting graduate school in bioengineering. During that year Karl went through scuba instructor training at the University of Michigan with Dr. Somers and got to know Dan Orr (now president of DAN) who, at the time was running the scuba program at Wright State University in Ohio.

    Going Over the Edge



    Huggins first publication on decompression tables was, "New No-Decompression Tables Based on No-Decompression Limits Determined by Ultrasonic Bubble Detection."

    -hh, muddiver, couv and 8 others like this.
    Comments 31 Comments
    1. TSandM's Avatar
      TSandM -
      Very interesting and very well written article! I enjoyed reading it; thank you.
    1. Steve Barsky's Avatar
      Steve Barsky -
      Glad you enjoyed it. Karl is a very modest person who deserves more recognition for his great contributions to diving.
    1. caseybird's Avatar
      caseybird -
      Nice article. I remember seeing a friend showing us an Orca about 1988 -89? It was at least 12 years before I began diving. I liked the way it displayed the compartments. It was very impressive.
    1. Steve Barsky's Avatar
      Steve Barsky -
      Thank you for your kind words!
    1. -hh's Avatar
      -hh -
      Very nice.There's been a lot of quiet pioneers whose works have improved both the quality and safety of diving by such work as Karl's, which made "non-military/commercial" (ie, non-square) dive profiles much more practical for the recreational diver in particular. And for the armchair historian, there's a lot more dive history to go delve into.I still have my old EDGE at home ... I'll have to go put a fresh 9V battery in it to see that it still is kicking. Perhaps I'll take it along on my next dive trip just to have fun with the Divemasters with it ...and if someone were to duplicate the EDGE's "Bar Chart" interface, I'd do what I told ORCA/EIT's Phillip May (RIP) many years ago: I'd buy what we called an "Edge-II" in a heartbeat. Its GUI is really a great illustration of the status of the controlling compartments, and nearly the perfect UI for the knowledgable diver to apply.-hh
    1. Steve Barsky's Avatar
      Steve Barsky -
      Some of the other "quiet pioneers" are:

      Bob Stinton, at DUI, who has done the grunt work on DUI's dry suits

      Pete Ryan, at Kirby Morgan, who did most of the engineering work on the EXO mask and many Kirby Morgan helmets

      Jerry Peck, the chief engineer at Ocean Technology Systems, who has developed most of their electronics

      All of these guys deserve way more recognition than they have received.
    1. drbill's Avatar
      drbill -
      Nice job, Steve. Karl certainly is a modest man who has done much to promote safer diving.
    1. Steve Barsky's Avatar
      Steve Barsky -
      Thank you, Dr. Bill!
    1. Texfrazer's Avatar
      Texfrazer -
      Awesome article Steve!It is great to know more about the men who have shaped modern diving. Thanks!!!
    1. Steve Barsky's Avatar
      Steve Barsky -
      Many thanks for your kind words.
    1. Blair Mott's Avatar
      Blair Mott -
      Great information as most of us know the unit, but not the man behind it. Where would be without Karl's invention? Thanks for keeping us informed about our diving history.
    1. Mark Guccione's Avatar
      Mark Guccione -
      Nice work Steve.
    1. Duke Dive Medicine's Avatar
      Duke Dive Medicine -
      Steve, thanks for the article and for giving Karl some well-deserved attention. Nice work.
    1. Steve Barsky's Avatar
      Steve Barsky -
      Thank you!'
    1. Karl Huggins's Avatar
      Karl Huggins -
      To clarify, the EDGE was not my invention, I helped develop it. It was the brainchild of Craig Barshinger who founded Orca Industries and pulled the team together to develop his idea into the EDGE. Without Craig the EDGE never would have happened and the Swiss Table reading Decobrain would have been the only dive computer available in the early 1980s. FYI: Craig is now Senator Barshinger, Senator at Large for the US Virgin Islands.

      Quote Originally Posted by Blair Mott View Post
      Great information as most of us know the unit, but not the man behind it. Where would be without Karl's invention? Thanks for keeping us informed about our diving history.
    1. HBDiveGirl's Avatar
      HBDiveGirl -
      Quote Originally Posted by Steve Barsky View Post
      Glad you enjoyed it. Karl is a very modest person who deserves more recognition for his great contributions to diving.
      So True! Thank you, Steve, for a well written story that needed to be told. Excellent! Thanks to Karl for.... well, for a very long list of enhancements to our wonderful world of diving.
    1. John C. Ratliff's Avatar
      John C. Ratliff -
      Steve and Karl, thank you for the article. As a "vintage diver," I've just recently gotten into diving with a computer. It's great to hear about its development. And Karl, thank you for mentioning Craig Barshinger. I looked up his profile here. Now I keep wondering about what my life would have been like had I taken a NAUI Instructor position in the U.S. Virgin Islands in about 1978? Well, we can all do that, and I would not trade what I've experienced for that, but those little decisions make a vast difference in what we do. Thanks for the information.

      SeaRat
    1. Steve Barsky's Avatar
      Steve Barsky -
      Karl continues to contribute to diving all the time. This month he traveled to Kwajalein Island to put on an Emergency Dive Accident Management course. He also lectured to the dive boat captains in So Cal this past week.
    1. Seastarson's Avatar
      Seastarson -
      Ah, the Edge! I had one of those!! Had all the Orca computers, and now, I dive Cochran exclusively. Computers have come such a long way!! As we all have I suppose!
    1. Steve Barsky's Avatar
      Steve Barsky -
      Yes, we used all the Orca computers, too (and have a couple Kristine still has stashed away). We've also used Scubapro, AquaLung, Cochran, and currently Oceanic.
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