Category: Technical Diving Articles


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 risks

The Biggest Risk in Technical Diving (and how to avoid it) by Andy Davis There are old divers. And there are bold divers. But there are few old, bold divers. The biggest risk in technical diving is, quite simply, not having the capacity to resolve the next hazardous incident that occurs to you. This applies […]

nitrogen-narcosis-symtoms-signs

Nitrogen Narcosis – Perceptions of Susceptibility Examining the human factors influencing diver perceptions of susceptibility to nitrogen narcosis.  By Andy Davis Nitrogen narcosis is a hyperbaric neurological phenomenon. Its existence, symptoms and onset are known, even if medical science has not yet explained the physiological mechanisms causing it. Individual susceptibility to  the effects  of nitrogen […]

complacency-signal-scuba-technical-diving

Technical Diving – The Experience Paradox by Andy Davis. Many technical divers assume that acquiring greater training and experience must increase safety.  This is a flawed assumption. Accident statistics in technical diving, along with other sporting and industrial fields, show a distinct tendency for elevating risk as significant experience accumulates. The reason is complacency. A […]

sheck exley

Sheck Exley’s Razor – The Nature of Limits By R.D. Milhollin (Blog editor’s note: This article was first published in the March-April 1995, issue of Underwater Speleology. I have added it here on my blog to preserve and disseminate further, what I believe to be beneficial insights into overhead and technical diving knowledge). Sheck Exley was one […]

how to tie a regulator bungee necklace 1

How to Tie a Regulator Bungee Necklace Technical, sidemount and hogarthian configuration scuba divers utilize a regulator bungee necklace for stowage of the short hose back-up.  These regulator bungee necklaces are available for purchase in many scuba shops.  The manufactured ones are made of rubber, costs are relatively high and there is no option for […]

prestige diving

Are You A Prestigious Diver? by Andy Davis There are many motivations that drive divers to pursue higher level, more advanced qualifications and skills. There are many reasons why advanced divers are attracted to one agency, or methodology , or equipment brand over another. Some divers undertake further training and more ambitious dives, because they […]

diy-custom-sidemount-harness

How To Build Your Own DIY Custom Sidemount Harness by Andy Davis It’s pretty easy (and cheap!) to make a DIY custom sidemount harness for yourself. Configure it using THESE instructions.  All the components can be bought off-the-shelf at any decent dive centre; with the exception of the sidemount shoulder and lumbar plates, which you’ll […]

Decompression Sickness And the Immune System 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 reaction is as follows: […]

Sidemount-Harness-Setup-Configuration

Ultimate Guide : How To Set Up Your Sidemount Harness by Andy Davis A lot of divers find setting up a sidemount harness to be confusing, even those with experience diving backmount style wings.  Here’s my ultimate guide to setting up, sizing and configuring your sidemount harness. This article deals with ‘Mexican cave’ (aka UK) […]

sidemount cylinder trim

Ultimate Guide to Sidemount Cylinder Trim by Andy Davis This is my comprehensive guide to the good, the bad and the ugly of sidemount cylinder trim.  The aim of this article is to illustrate and explain the common errors that cause less than ideal sidemount trim and frustrate sidemount divers. Use the illustrations and diagrams […]

observe-analyse-adapt technical diving performance development

Performance Development for Technical Divers Observe – Analyze – Adapt by Andy Davis As a technical diving instructor, a primary aspect of my work is the process of observing diver performance (both in my students and their peers across the diving community), analyzing successes and limitations and finding the root causes for them; before adapting […]

nitrogen-narcosis-critical-flicker-frequency-fusion-study

Does Nitrogen Narcosis Impairment Persist? by Andy Davis. A new study on nitrogen narcosis challenges the long held presumption that nitrogen narcosis impairment dissipates immediately on ascent from depth.  A scientific study, ‘Persistence of Critical Flicker Fusion Frequency Impairment; Evidence of Prolonged Nitrogen Narcosis,’ first published in 2012 in the European Journal of Applied Physiology, by Costantino […]

human factors in diving course

A Review of the Human Factors in Diving Course by Andy Davis   I was recently given the opportunity to undertake the online Human Factors in Diving course.   The online version of this course is self-contained, but also acts as a primer to the full course which is delivered in a classroom.  Here’s my […]

sidemount technical diving training course subic bay

Goal Setting for Technical Diving Training by  Andy Davis Technical diving is a serious endeavor, that requires a significant commitment in respect of money, time and effort.  For that reason, very few divers embark on technical diving training without having some sort of plan of what they wish to achieve in the long-term. Setting long […]

technical diving computer perdix

The Best Technical Diving Computers 2017 Here’s my list of the best open circuit technical diving computers on the market in 2016.  I am only including ‘true’ technical diving computers; because there’s some awful impostors on the market nowadays.  Simply boasting multiple gasses and/or trimix capability does NOT make a computer ideal for modern technical […]

technical-diving-philippines-subic bay courses instructor lessons

Prepare Yourself For Technical Diving by Andy Davis Technical diving is increasingly becoming more mainstream as a diving activity; and that is a good thing.  Many more divers are now opting to pursue tech training as a means to increase the range of their potential diving and enjoy new experiences in their favorite hobby. However, […]

Mildly Bent – Decompression Stress and Micro-Bubbles Sub-Clinical DCS Bubbles occur in our bodies on 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 symptoms are named […]

Types of Decompression Sickness (DCS) 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) Type 2: Cardiovascular/Pulmonary […]

doc deep garman fatal world depth record attempt scuba diving accident

A Fatal Attempt: Dr Guy Garman’s World Depth Record 2015 Analyzing The Psychological Factors That Can Lead A Team Into A Destructive Goal Pursuit.  On the 15th August 2015, the technical diving community received sad news that the latest World Depth Record attempt, to 1200ft/365m) had ended in tragedy when the participant, Dr Guy Garman, […]

technical-diving-formulas

Technical Diving Formulas The scanned page below highlights key formulas for technical diving.  This is useful as a review, or for technical diving students preparing for courses.

best ascent speed for scuba diving

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

technical diving subic bay philipines

Technical Diving Skills – Valve Shutdown Drill Explained This article, posted at Dive DIR, provides a very clear explanation of valve shutdown drills for isolated manifold doubles/twinset cylinders. Great reading, if you are thinking about technical diving or just doing recreational scuba dives with doubles cylinders. A sample: Tuesday, 02 November 2010 17:39 This article […]

technical diving subic bay philipines

Technical Diving Skills – Reaching Your Valves This article, posted at DiveDIR, gives great advice on how to reach your valves when conducting valve shutdown procedures.  It’s the most comprehensive analysis of this key skill attribute that I’ve read to date.  They call it the ‘ultimate guide’… it really is! Direct Link: http://www.divedir.com/Drills-and-Skills/valve-drills-the-ultimate-guide.html Sample: Reaching Your […]

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) […]

Sidemount Technical Wreck Diving Subic Bay Philippines

Tech Diving – Turn Pressure Calculator Use this spreadsheet to help calculate your turn pressure on technical/overhead dives: turn_pressure_calculator