Oops! It appears that you have disabled your Javascript. In order for you to see this page as it is meant to appear, we ask that you please re-enable your Javascript!

Tag Archive: decompression


Mildly Bent – Decompression Stress and Micro-Bubbles by Andy Davis Sub-Clinical DCS Bubbles occur in our bodies on the ascent from most scuba dives, but those bubbles have to reach a sufficient size before they cause enough immediate harm to present diagnoseable symptoms of DCS. Bubbles of insufficient size to cause clinically identifiable decompression sickness […]

Decompression Sickness And the Immune System by Andy Davis It is known that bubbles within the body trigger an immune system response. For this reason, immune-suppressant drugs are often administered during hyperbaric treatment for decompression sickness.  The immune system reacts to bubbles as it would to any foreign body; such as a virus or bacteria. That […]

Technical versus Recreational Scuba Diving:  Why is there a need for Rules, Boundaries and Limitations? There is currently a strong debate about the need to differentiate between recreational and technical scuba diving. Some people believe that ‘diving is diving’ and question the need to draw a distinct boundary between recreational and technical diving pursuits. In […]

best ascent speed for scuba diving

Best Ascent Speed for Scuba Diving by Andy Davis Disclaimer: The opinions expressed in this article are those of the author, and they do not reflect in any way those of the dive training agencies to which he is affiliated. Information presented in this article is not intended to advocate breaching the Safe Diving Practices taught […]

scuba-tips-advice-how-to-professional

Scuba Q and A: Why Do Decompression Divers Use Nitrox? Q. Why do decompression divers need to use nitrox in the shallower part of their dive? Answer: A diver absorbs or releases inert gas based on the positive or negative partial pressure differential of those gases in their breathing mix and body tissues. We only […]

VPM varying permeability model

VPM For Dummies The Varying Permeability Model (VPM) for Dummies By Kevin Watts   Blog editorial:  I reproduced this article, for wider dissemination, from it’s original location at RebreatherWorld forum This article attempts to provide a basic framework for looking at the VPM. My hope is that a diver who may be intimidated or frustrated […]

Types of Decompression Sickness (DCS) by Andy Davis Decompression sickness is caused by inert gases leaving solution inside the body and forming bubbles. If allowed to grow sufficiently large, those bubbles present signs and symptoms, which allow DCS to be diagnosed, such as; Type 1:  Minor. Localized pain, skin itching (Pruritis) and skin rash (Cutis marmorata) […]

decompression theory technical diving

Decompression Theory – Links and Resources Here is my selection of educational articles and resources for further reading on scuba diving decompression theory… –  Bubble Decompression Strategies by Eric Maiken –  VPM Decompression Site by Eric Maiken –  Confessions of a Mortal Diver by Richard Pyle –  The Importance of Deep Stops by Richard Pyle –  Half-Times Explained by Mark Powell –  Deco Lessons by Erik Baker (pdf) […]

subclinical dcs decompression stress

Subclinical DCS, Decompression Stress and Post-Dive Fatigue by Andy Davis Post-Dive fatigue, malaise, lethargy, sleepiness and decreased vitality is an often-observed consequence of scuba diving.  Many divers can relate with this; having felt sluggish and in dire need of a snooze during surface intervals or after diving. Is it really normal and expected? Is it […]

technical diving subic bay philipines

An abridged version of this deep stops article was originally in DeepTech, 5:64; and the full version subsequently published in Cave Diving Group Newsletter, 121:2-5. The Importance of Deep Stops: Rethinking Ascent Patterns From Decompression Dives by Richard L. Pyle Before I begin, let’s make something perfectly clear: I am a fish-nerd (i.e., an ichthyologist). […]

Gradient Factor Comparison Using A Simple 60m Trimix Dive Case-Study By Andy Davis. As a follow-up to my previous article, ‘A Logical Application of Gradient Factors Settings for Open-Circuit Tech Divers‘, I have decided to write a comparative case-study that illustrates the effect that three different gradient factor settings can have on the dynamics of […]

gradient-factors-use-settings-decompression

A Logical Application of Gradient Factors Settings for Open-Circuit Tech Divers by Andy Davis As an active technical diving instructor for many years, I see many tech divers struggling to use Gradient Factors to their full advantage. This article explains my own systematic and easily applicable approach to setting Gradient Factors for optimal off-gassing effect. […]

TDC-3 technical diving computer

The Best Technical Diving Computers 2019 by Andy Davis Here’s my list of the best open circuit technical diving computers on the market in 2019. Note: I am only including ‘true’ technical diving computers; because there are some awful impostors on the market nowadays.  Manufacturers may simply boast that a computer offers multiple gasses and/or […]

Scuba World Depth Records – Science versus the Human Factor – Perspective on the future of scuba world depth records; the issue of human versus scientific & technological limitations on extreme diving depth.  by Andy Davis The way I see it, there are two ‘types’ of serious world records; those primarily dependent on human factors […]

Erik Baker Deep Stops 1

Clearing Up The Confusion About Deep Stops By Erik C. Baker The old adage, “an ounce of prevention is worth a pound of cure”, is certainly applicable to the various symptoms of decompression sickness (DCS). The best treatment of all for these maladies is to complete a sufficient decompression profile in the first place. Technical divers […]

Understanding M-Values By Erik C. Baker In conjunction with an array of hypothetical “tissue” compartments, gas loading calculations and M-values compose the major elements of the dissolved gas or “Haldanian” decompression model. Through the use of widely-available desktop computer programs, technical divers rely on this model for their decompression safety. A good understanding of M-values can […]

gradient factors

Gradient Factors by Matti Anttila Ph.d Remember your first diving classes and the lesson about bubbling soda bottle and too rapid ascents? No matter how deeply you study the decompression theory, this soda bubble analogy is still valid. However, it’s time to introduce some more fundamentals of the issue. But let’s start from the history: […]

Technical Diving Theory Sidemount Diving

Gradient Factors for Dummies By Kevin Watts (Article from RebreatherWorld.Com) This article attempts to provide a user’s view of gradient factors, an Erik Baker derived method of calculating decompression schedules. The title is not meant to be derisive, but simply an indicator that this article is meant to be a primer. Back to Buhlmann Everything […]

Sidemount Technical Wreck Diving Subic Bay Philippines

Decompression Gases – Efficiency Ratios Deco Gas Efficiency Ratio Air 1:1 32% 1:1.6 36% 1:1.21 40% 1:1.26 50% 1:1.32 80% 1:1.36 100% 1:1.40 Theoretical efficiency ratios for decompression gas options.