Dive Computers – Insights for Divers & Professionals. Wolfgang Wild

      Incl. 58 illustrations

      © 2014 by Wolfgang Wild. All rights reserved.

      Publisher: epubli GmbH, Berlin (Germany)

      www.epubli.de

      ISBN: 978-3-7375-0616-8

      No part of this book may be reproduced in any written, electronic, recording, or photocopying without written permission of the publisher or author. The exception would be in the case of brief quotations embodied in the critical articles or reviews and pages where permission is specifically granted by the publisher or author.

      Although every precaution has been taken to verify the accuracy of the information contained herein, the author and publisher assume no responsibility for any errors or omissions. No liability is assumed for damages that may result from the use of information contained within.

      Cover Design: propublishing

      Cover Pic: innovasub.com, with kind permission

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       Introduction

       What exactly does “conservative” mean in diving?

       Dive Tables – the STUP effect

       An example for reliably developed, validated and documented dive tables – the Recreational Dive Planner (RDP)

       Reflections on a proper ascent rate

       Excursus – How do divers control their ascent rate?

       Saturation, halftime and M-value

       Halftime

       M-value

       Doppler ultrasound and other ways to detect bubbles in our tissues

       Understanding decompression sickness

       ”Tissue Model” vs. “Bubble Model”

       Tissue Model / 1-phase model

       Bubble Model / 2-phases model – Part One

       The Buhlmann models ZH-L12 and ZH-L16

       Gradient factors

       Bubble Model / 2-phases model – Part Two

       The attack on bubbles at depth

       The VPM model

       The RGBM model

       Deep Stops – what is that?

       Which stop-depth is the correct one?

       What to do? STUP is for divers no real alternative!

       Dive computers in practice

       From table towards computer – multilevel diving

       Preliminary evaluations of dive data banks – Wienke & DAN

       Dive Computers 1994 – results of own practice tests

       Dive Computers 2009 – practice test magazine Diver

       Dive Computers 2009 – practice test magazine Scuba Diving

       Practice tests in the hyperbaric chamber – Catalina Island (USA) 2011

       The crux with technology

       Closing chapter and perspectives

       Requirements for the validation of dive computers

       Dreams of the future – alternatives to the traditional dive computer

       Bibliography and Internet Links

      1 – Introduction

      Dive Computers – Computers?

      Here a selection of dive computer recalls published on the homepage of the Consumer Product Safety Commission (CPSC) which is in charge of consumer protection in the United States of America:

      • AERIS Epic – decompression hazard

      • Atomic Aquatics Cobalt – impact injuries and drowning hazard

      • Dacor Darwin Air – serious injuries, including decompression sickness

      • Hollis DG03 – drowning hazard

      • Mares Nemo Air – drowning hazard

      • Oceanic ATOM 2.0 – decompression hazard

      • UWATEC Aladin Air X NitrOx – possible decompression sickness

      Source: www.cpsc.gov

      These few examples of dive computer recalls do not only concern various manufacturers, but also different mathematical calculation models (aka algorithms) and varied technical problems of our popular dive companions: A display which fails to display under water, a leaking O-ring leading to wrong remaining air times under water, a software defect which is known by the manufacturer who is forced seven years later to admit this before a United States District Court (see bibliography, San Francisco Chronicle) etc. etc. The reader will be well aware of such product recalls not being limited to diving equipment, and they are not only nerving, but actually inacceptable for us as consumers when our safety is concerned. Visiting above US government website cpsc.gov or using your favorite search engine and the proper term for “product recall” in your language reveals horrifying results. Aren’t we supposed to have fun when we go diving, and isn’t safety a prerequisite for that?

      From the mechanic-pneumatic one-tissue (!) Decometer in 1959 (USA) via the legendary EDGE (USA, 1983) and Deco-Brain (Switzerland, 1983/1985) to present-day models, the dive computer has come a long way – more than half a century.

      And the research which divers know as decompression theory is quite a bit older. If we take John Scott Haldane as “father” of all dive tables in 1908 this history extends well over one hundred years.

      All diver training associations still regard it important that divers learn in any way why and how our body tissues are being enriched by gases which constitute the gas mixture divers breathe under water. And it is also still regarded essential for divers to get to know and manage the tools that are designed to avoid problems from this absorption of gases which always takes place in us when we use a “self-contained under water breathing apparatus” (aka “scuba”) to seek adventure and recreation in our fascinating under water realm.

      Some diver training associations continue to proceed via the dive table, others