Dive Computer - History

History

The Office of Naval Research funded a project with the Scripps Institute of Oceanography for the theoretical design of a prototype decompression analog computer. The Foxboro Decomputer, Mark I was manufactured by the Foxboro Company and evaluated by the US Navy Experimental Diving Unit in 1957. Confusion between the diffusivity coefficient and the then new concept of tissue half time resulted in a device that did not properly mirror decompression status. Had this error not occurred, the U.S. Navy Tables might never have been developed, and divers might have been using instrumentation to control their dives from 1957 on.

The first recreational mechanical analogue dive computer, the "decompression meter" was designed by the Italians De Sanctis & Alinari in 1959 and built in their factory named SOS, which also made depth gauges. The decompression meter was distributed directly by SOS and also by scuba diving equipment firms such as Scubapro and Cressi. It was very simple in principle: a waterproof bladder filled with gas inside a big casing bled into a smaller chamber through a semi-porous ceramic cartridge (to simulate tissue in/out gassing). The chamber pressure was measured by a bourdon tube, calibrated to indicate decompression status. The device functioned so poorly that it was eventually nicknamed "bend-O-meter".

In 1965, Stubbs and Kidd applied their decompression model to a pneumatic analogue decompression computer.

Several analogue decompression meters were subsequently made, some with several bladders for illustrating the effect on various body tissues, but they were sidelined with the arrival on the scene of electronic computers.

In 1980/81, the Hans Hass DecoBrain, designed and invented by D.I. Juergen Hermann a Swiss electronic engineer, became the first popular decompression diving computer, capable of displaying the information that today's diving computers do. The Deco Brain was based on Prof. Dr. A. Bühlmann's 16 compartment (ZHL-12) tissue model which Hermann implemented on one of Intel's first single-chip microcontrollers as part of his thesis at the Swiss Institute of Technology. Hermann marketed the Deco Brain from 1982 on; in the following years he miniaturized diving computers to the size of a match box (called Micro Brain, DC11, DC12, TRAC and others), and finally sold his company, Divetronic AG, to Scubapro for several million US dollars in 1991. Today, Scubapro/Uwatec is still one of the leading diving computer manufacturers. At that time, only the Deco Brain was able to compute and display a decompression plan, displaying the total ascent time, the related decompression stops and decompression times.

The 1984 Orca EDGE was an early example of a dive computer. Designed by Craig Barshinger Karl Huggins and Paul Heinmiller, the EDGE did not display a decompression plan, but instead the EDGE showed the ceiling or the so-called "safe-ascent-depth". A drawback was that if the diver was faced by a ceiling, he did not know how long he would have to decompress. The EDGE's large, unique display, however, featuring 12 tissue bars permitted an experienced user to make a reasonable estimate of his or her decompression obligation.

In 1984 D.I. Juergen Hermann also developed the US Navy diving computer (UDC) which was based on a 9 tissue model of Dr. Edward D. Thalmann of the Naval Experimental Diving Unit (NEDU), Panama City, who developed the US Navy tables. Hermann completed the UDC development – as it had been started by the chief engineer Kirk Jennings of the Naval Ocean System Center, Hawaii, and Dr. Thalmann of the NEDU – by adapting the Deco Brain for US Navy warfare use and for their 9-tissue MK-15 mixgas model under an R&D contract of the US Navy. Divetronic also received further R&D work from the US Navy in the following years and received US Navy approval for their UDC's.

Even by the late 1980s, the advent of Dive Computers had not met with what might be considered widespread acceptance. Combined with the general mistrust, at the time, of taking a piece of electronics that your life might depend upon underwater, there were also objections expressed ranging from the ridiculous (dive resorts felt that the increased bottom time would upset their boat and meal schedules) to the sublime (knowledgeable divers felt that the increased bottom time would, regardless of the facts, result in many more cases of Decompression sickness). Understanding the need for clear communication and debate, Mr. Michael Lang of the California State University at San Diego and Dr. William Hamilton of Hamilton Research Ltd. brought together, under the auspices of the American Academy of Underwater Sciences a diverse group that included most of the dive computer designers and manufacturers, some of the best known hyperbaric medicine theorists and practitioners, representatives from the recreational diving agencies, the cave diving community and the scientific diving community.

The basic issue was made clear by Dr. Andrew A. Pilmanis, in his introductory remarks: "It is apparent that dive computers "are here to stay" but are still in the early stages of development. From this perspective, this workshop can begin the process of establishing standard evaluation procedures for assuring safe and effective utilization of dive computers in scientific diving."

After meeting for two days the conferees were still in, "the early stages of development," and the "process of establishing standard evaluation procedures for assuring safe and effective utilization of dive computers in scientific diving," had not really begun. University of Rhode Island Diving Safety Officer Phillip Sharkey and ORCA EDGE's Director of Research and Development, prepared a 12 point proposal that they invited the Diving Safety Officers (DSO) in attendance to discuss at an evening closed meeting. Those attending included: Jim Stewart (Scripps Institution of Oceanography), Lee Somers (University of Michigan), Mark Flahan (San Diego State University), Woody Southerland (Duke University), John Heine (Moss Landing Marine Laboratories), Glen Egstrom (University of California, Los Angeles), John Duffy (California Department of Fish and Game), and James Corry (United States Secret Service). Over the course of several hours the suggestion prepared by Sharkey and Heinmiller was edited and turned into the following 13 recommendations:

1. Only those makes and models of dive computers specifically approved by the Diving Control Board may be used.
2. Any diver desiring the approval to use a dive computer as a means of determining decompression status must apply to the Diving Control Board, complete an appropriate practical training session and pass a written examination.
3. Each diver relying on a dive computer to plan dives and indicate or determine decompression status must have his own unit.
4. On any given dive, both divers in the buddy pair must follow the most conservative dive computer.
5. If the dive computer fails at any time during the dive, the dive must be terminated and appropriate surfacing procedures should be initiated immediately.
6. A diver should not dive for 18 hours before activating a dive computer to use it to control his diving.
7. Once the dive computer is in use, it must not be switched off until it indicates complete outgassing has occurred or 18 hours have elapsed, whichever comes first.
8. When using a dive computer, nonemergency ascents are to be at the rate specified for the make and model of dive computer being used.
9. Ascent rates shall not exceed 40 fsw/min in the last 60 fsw.
10. Whenever practical, divers using a dive computer should make a stop between 10 and 30 feet for 5 minutes, especially for dives below 60 fsw.
11. Only 1 dive on the dive computer in which the NDL of the tables or dive computer has been exceeded may be made in any 18-hour period.
12. Repetitive and multi-level diving procedures should start the dive, or series of dives, at the maximum planned depth, followed by subsequent dives of shallower exposures.
13. Multiple deep dives require special consideration.

As recorded in "Session 9: General discussion and concluding remarks:" "Mike Lang next lead the group discussion to reach consensus on the guidelines for use of dive computers. These 13 points had been thoroughly discussed and compiled the night before, so that most of the additional comments were for clarification and precision. The following items are the guidelines for use of dive computers for the scientific diving community. It was again reinforced that almost all of these guidelines were also applicable to the diving community at large."

The remarkable thing about this process is that after the AAUS workshop the opposition to Dive Computer crumbled, numerous new models were introduced, the technology dramatically improved and Dive Computers became, virtually overnight, the standard pieces of diving equipment that they are today.

In 2001, the US Navy approved the use of Cochran NAVY decompression computer with the VVAL 18 Thalmann algorithm for Special Warfare operations.

In 2008, the Underwater Digital Interface (UDI) was released to the market. This dive computer, based on the RGBM model, includes an underwater communication system that enables divers to transmit text messages, also featuring SOS and homing capabilities, and digital 3D compass.