Depth Notes
Field notes and dive theory from the depths.
Reading Your Dive Computer in Real Time
June 19, 2025 · 9 min read
How to use GF99 and Surface GF as live operational tools, what ascent rate data shows, and understanding what your algorithm cannot see — subclinical DCS, individual physiology, and the limits of the model.
Decompression Algorithms: ZHL-16C, RGBM, and VPM
June 12, 2025 · 7 min read
The three decompression models running inside modern dive computers — what separates dissolved-gas models from bubble models, how they handle repetitive dives differently, and what the outcome data actually shows.
Fit to Dive
June 9, 2025 · 9 min read
How chronic conditions like asthma, hypertension, and diabetes interact with diving safety — plus what physical conditioning actually looks like for a diver who wants to stay safe underwater.
Post-Dive Fatigue
June 9, 2025 · 6 min read
The two mechanisms behind post-dive fatigue — physical workload and subclinical decompression stress — and what you can actually do about each of them.
Pulmonary Barotrauma & AGE
June 9, 2025 · 8 min read
What pulmonary barotrauma is, how arterial gas embolism happens, and why even a shallow ascent with a closed airway can cause a life-threatening emergency.
Immune Suppression and Diving
June 8, 2025 · 6 min read
Why repetitive or deep diving temporarily suppresses immune function, what ROS and cytokines have to do with it, and how to recover properly between dive days.
Thermal Stress in Diving
June 8, 2025 · 8 min read
How cold water changes nitrogen off-gassing during decompression, why your dive computer can't account for it, and what thermal protection gear you actually need at depth.
Dive Computers: How They Actually Work
June 5, 2025 · 7 min read
What your dive computer is doing beneath the display — how it models nitrogen loading every few seconds, what every reading means, and the mistakes that turn a safety tool into a liability.
Predisposing Factors for Decompression Sickness
June 3, 2025 · 9 min read
Why identical dive profiles produce different outcomes in different divers — the physiological, environmental, and behavioural factors that shift decompression risk beyond what any algorithm can predict.
Diver Risk & Physiology
June 2, 2025 · 7 min read
What decompression sickness actually is, how nitrogen bubbles form, what they do to the body, and the basics of prevention — a practical primer for any diver.
Pulmonary Oxygen Toxicity
June 1, 2025 · 5 min read
Pulmonary oxygen toxicity — how it differs from CNS toxicity, what OTUs and the Arieli K-Index actually measure, and why CCR divers on long exposures need better tracking tools than a single daily limit.
CNS Oxygen Toxicity
May 31, 2025 · 7 min read
CNS oxygen toxicity — what actually happens in the brain when PO₂ gets too high, how risk accumulates over time, and how to manage oxygen exposure in technical and CCR diving.
Oxygen Toxicity & ROS
May 30, 2025 · 7 min read
What reactive oxygen species are, how they form at elevated PO₂, why diving accelerates their production, and how this connects to both CNS and pulmonary oxygen toxicity.
Gas Density and CO₂ Buildup
May 29, 2025 · 7 min read
Why gas density increases with depth, how CO₂ retention happens even when you think you're breathing normally, and why this is one of the most underestimated risks in deep diving.
Inert Gas Narcosis
May 29, 2025 · 8 min read
What inert gas narcosis actually does to your brain at depth — the membrane and protein mechanisms behind it, why the martini analogy undersells the risk, and how helium changes the picture.
M-Values, Half-Times, and Tissue Compartments
May 28, 2025 · 8 min read
How Haldane's tissue compartment model works, what half-times and M-values actually represent, and why your dive computer's decompression ceiling is only as accurate as the physics it assumes.
Gradient Factors & Dive Computers
May 23, 2025 · 9 min read
What gradient factors actually are, how GF Low and GF High shape your ascent, and why every diver using a modern computer should understand the numbers behind their decompression ceiling.
The Benefits of Nitrox
May 23, 2025 · 6 min read
Enriched Air Nitrox — how it extends no-decompression limits, why it matters for repetitive diving, and what the actual risks are if you get the planning wrong.
Breathing Underwater: A Guide to Diving Physiology
May 22, 2025 · 7 min read
What changes when you breathe underwater — gas density, partial pressures, and why every breath at depth is more complex than it looks on the surface.
Bubble Models
May 22, 2025 · 7 min read
How bubble models like VPM and RGBM differ from standard gas content algorithms, why microbubbles matter even on clean profiles, and what the research actually says about deep stops.
Sponges, Soda Bottles, and Safe Ascents
May 22, 2025 · 7 min read
How gas content models work, what tissue compartments and M-values actually represent, and why your dive computer is making calculations on every second of every dive.