P.O.D.I.

A Brief Explanation AS UNDERSTOOD BY SKIP

Technical diving is what happens when recreational diving and poor financial decisions have a baby that owes money to the gas supplier. It involves deeper depths, longer bottom times, multiple gas bottles, decompression stops, and at PODI, a complete absence of any of the training that normally accompanies these activities. Skip describes it as "when you bring two of everything and still run out of gas." We printed that on a shirt. We sell it for $35. It costs $28 to make. We have sold four. The four people who bought it all asked about helium. They are on the list.

A Glossary of Terms ACCURATE ENOUGH TO SOUND SMART ON A DIVE BOAT

Real tech divers have a vocabulary that separates them from the recreational crowd. We have memorised these words. We do not know what half of them mean. But we say them with confidence, usually while adjusting a piece of gear we have no business touching.

Our Gear Philosophy HOGARTHIAN? WE ARE DADAIST. NOTHING MATCHES. NOTHING WORKS.

Real tech divers follow the Hogarthian / DIR (Doing It Right) philosophy: a standardized, minimalist, and rigorously consistent gear configuration. Every bolt snap is in the same place. Every hose is the same length. Every backup is identical to the primary. The goal is that in an emergency, your muscle memory works even in total darkness. PODI's philosophy is the opposite. We call it "Doing It Random." Our rigging changes week to week based on what Gary found on sale. Your primary regulator is a Scubapro. Your backup is a Cressi that came with a starter kit. The hoses are different lengths. One is yellow. One is black. Your long hose is 7ft on the left side and 4ft on the right because we ran out of 7ft hose. Your backup regulator is on a necklace made of paracord that Derek tied himself. It will not break. It is not adjustable. It will choke you gently for the entire dive. Our twin-tank manifold is an isolator valve from a salvage shop. The isolator knob is stripped. It is permanently in the "open" position. If you have a catastrophic right-post failure, you will empty both tanks into the water column and we will wave at the bubbles. Our wing is 40lbs for a set of 12L doubles. We do not know where the other 10lbs of buoyancy went. We assume it is "somewhere in the loop." We do not have a drysuit. We dive wet at 6°C because "your core will warm up eventually." It does not warm up eventually. You will shiver through your deco stop. The shivering is good. It moves the blood. The blood has the gas in it. It is fine. Everything is fine.

PODI Gas Services PARTIAL PRESSURE? FULL PRESSURE. LOW STANDARDS.

Real tech dive shops blend gas using partial-pressure methods: they calculate the exact amount of oxygen, helium, and air needed, fill them sequentially using a booster or bank system, let the cylinder sit overnight to "vortex" (the gases mix by themselves if you are patient), and analyze the result with a calibrated analyzer. PODI Gas Services uses the "close enough" method. We fill your tank with whatever comes out of the hose first. Then we fill it with something else. Then we shake it. We do not know what is in there. We will analyze it once with our analyzer, which was dropped in 2019 and now reads in what appears to be Portuguese. If you ask for a specific blend, we will nod confidently, walk into the back room, and wait 10 minutes before coming out to say "the trimix machine is broken." There is no trimix machine. There never was a trimix machine. We bought a trimix machine once. It arrived in boxes. We did not open the boxes. The boxes are in the corner. They have become storage for other, smaller boxes.

O₂ Cleaning: Oxygen service requires all components to be cleaned of hydrocarbons to prevent spontaneous combustion under pressure. The official standard is CGA G-4.1. Our standard is "wipe it with a paper towel and if the paper towel comes back clean-ish, send it." We do not know what hydrocarbons are. Someone said "they are in everything." We assume that means it is fine.

Regarding Helium: No. The answer is no. We do not have it. We will not get it. If you arrive with your own helium, we will ask you to leave. If you insist, we will ask you to leave permanently. If you ask us where to get helium, we will say "try the internet" and close the door. We priced it once. The quote had so many zeros that Kyle asked if it was a phone number. He dialed it. It was a pizza place. He ordered a large pepperoni. It arrived in 30 minutes. It was hot. It was good. It was cheaper than helium. We have since ordered from that pizza place 47 times. That is 47 more times than we have ordered helium. We are okay with this.

Why We Don't Stock It HELIUM IS A NOBLE GAS. WE ARE NOT NOBLE. WE ARE BROKE.

Real tech divers know that helium is available in two grades: Grade A (99.995% pure, used for breathing, costs approximately your firstborn) and Grade D (98% pure, cheaper, but also used for welding. we are not sure if Grade D is breathable. we assume it is. we would probably buy Grade D. we cannot afford Grade D.) There is also a global helium shortage that has been ongoing since approximately 2012. Every tech diver has a story about a trip cancelled because the helium bank ran dry, or a fill scheduled weeks in advance, or paying $200 for a trimix fill and getting 17 minutes of bottom time out of it. Helium is a finite resource. It is also an expensive resource. We priced it once. The gas supplier asked if we were sitting down. We were sitting down. We sat down harder. The quote had so many zeros that Kyle asked if it was a phone number. We dialed it. It was a pizza place. We ordered a large pepperoni. It cost $18. We tipped $5. We ate the pizza. It was excellent. We have ordered from that pizza place 47 times since then. We have ordered helium zero times. The pizza place has never let us down. The pizza place understands our budget. We are loyal to the pizza place.

PODI Gas Planning Methodology RULE OF THIRDS? WE USE THE RULE OF "HOW MUCH AIR DOES IT FEEL LIKE THERE IS"

Real technical diving gas planning is a precise science. You calculate your SAC rate (litres per minute at the surface), multiply by depth in atmospheres, add a safety margin for stress, and divide your cylinder volume by that number. For stage bottles, you use the rule of halves instead of thirds because stage bottles are smaller and the margins are tighter. You plan for total gas failure of your deepest tank at the worst possible moment. You write your plan on a slate. You carry the slate. You reference the slate. You do not deviate from the slate. PODI's gas planning protocol is called "vibes-based pneumatics." You look at your SPG before you jump in, ask Skip how long the dive is, he says "I dunno, like 30 minutes?", you add 50 bar because "that sounds like enough," and you hit the water. Your SAC rate has never been calculated. You breathe like a cartoon character who just ran off a cliff. Your actual consumption at 45m is four times your surface guess. At minute 14, your SPG is at 50 bar. We call this a "gas conservation drill." If you surface with more than 30 bar, we reduce your fill pressure next time to "save money." You will not learn to breathe more efficiently. You will simply accept the fear.

Dive Computer Configuration GF 30/70? GF 40/85? GF WHO-KNOWS? THAT ONE.

Every tech diver uses a Shearwater Perdix 2 or Petrel 3 — they come in a plain brown box (no marketing, no fuss, just a screen and a lot of buttons you are afraid to press). The first thing you do is set your Gradient Factors. The internet will tell you 30/70 is conservative and 40/85 is standard. You will not know what this means. You will set it to 30/70 because the forum post was written in 2016 and has a lot of upvotes. You will never change it. Gary's computer is set to 30/70 from a dive trip in 2019. He has not changed it. He does not remember why he chose 30/70. He will defend it to the death. Kyle's computer is in "Freedive" mode. He does not freedive. He does not know what Freedive mode does. The screen shows different numbers than everyone else's. He assumes it is fine. Skip's computer still contains 47 dive logs from the previous owner, a man named "Brad." Skip has never cleared them. He simply subtracts 40 minutes from the displayed runtime and calls it "compensated." Derek's computer is in a drawer. It has never been turned on. He says he "dives by the seat of his pants." Derek's pants have guided him through four decompression-sickness incidents. Tiffany's computer is configured to GUE standards with a GF of 30/70, deep stops enabled, and a 1.4 PO₂ limit. She will look at your computer when you board the boat. She will sigh. That sigh will be louder than any alarm your computer can produce.

Advanced Deep (Beyond 40m) DEEP AIR IS NOT A THING. WE DO IT ANYWAY.

There is a reason real technical divers do not dive past 40 metres on standard compressed air. It is called nitrogen narcosis — Martini's Law states every 10 metres is the equivalent of one martini on an empty stomach. At 50 metres, you have had five martinis and are having a conversation with a fish that does not exist. At 60 metres, you are having a conversation with the fish about your childhood while your computer screams at you about your deco obligation. Real tech divers use trimix — a blend of oxygen, nitrogen, and helium — to keep the narcosis under control and the oxygen within safe limits. We use air because we priced trimix once and the number was so large that we assumed it was a phone number. We dialed it. It was a pizza place. We ordered a large pepperoni. It was delicious. It cost less than trimix. We have eaten approximately 47 large pepperonis since then. That is 47 more helium purchases than we have made. Our deco stops are performed at depths we estimate using the "vibe method" — you look at the water column, guess how far down 6 metres is, and hover there until your computer stops beeping. If your computer locks out, we call that a "successful deco drill." There is no drill. You are just locked out. You will guess your ascent. If you surface early and get bent, you will receive a free T-shirt that reads "I WENT DEEP AND ALL I GOT WAS THIS LOUSY DCI." We ordered 200. We have handed out 14. Everyone who got one came back for another dive. We do not know if this says something about the T-shirt or about our divers.

Rebreather Familiarization eCCR? mCCR? IT IS A GARAGE KIT. IT IS WHATEVER IT WANTS TO BE.

Real closed-circuit rebreathers (CCRs) are sophisticated life-support systems that maintain a constant partial pressure of oxygen using electronic solenoid injection (eCCR) or manual addition (mCCR). They use three oxygen sensors that vote on the PO₂ — if two sensors agree and the third disagrees, the third is wrong. The CO₂ is removed by a canister filled with Sofnolime (sorb), which must be packed correctly, sealed correctly, and replaced after every use or every 3 hours, whichever comes first. Properly configured, a CCR lets you breathe the same gas for hours, produce no bubbles, and explore depths that would be impractical on open circuit. Gary's rebreather does none of these things. It was assembled from a kit purchased at a police auction. The oxygen sensors are three different brands purchased from eBay. They do not agree on the PO₂. None of them are correct. The solenoid fires at irregular intervals based on what Gary describes as "vibe." We believe the solenoid is actually a sprinkler valve that Gary modified with a drill. The sorb in the canister was replaced "sometime after the pandemic." That is not a specific date. That is a range. The range is 2021 to 2024. The sorb is pink. It should be white. There are no more questions about the sorb. The pre-breathe check involves breathing on the loop for 3 minutes while watching the screens. If the PO₂ drops, you add oxygen. If it rises, you add diluent. If it stays the same, it is a miracle and you go diving. Our pre-breathe check takes 45 seconds and ends with Gary saying "good enough." The pool session will involve the loop flooding. It will flood immediately. Gary will say "that's never happened before." It has happened before. It has happened every time. Everyone will bail out to a spare regulator while Gary disassembles the unit on the pool deck. You will receive a certificate that says "Rebreather Familiarization — 1 Day." It does not specify whether the day included actual rebreather diving. It did not. The certificate is nonetheless valid. We have decided it is valid.

Decompression Procedures PLAN THE DIVE. DIVE THE PLAN. LOSE THE PLAN. IMPROVISE.

Real decompression procedure courses teach you to use proper deco software — MultiDeco, DecoPlanner, or Shearwater's built-in planner — to calculate a gradient-factor-based ascent schedule. You learn about Bühlmann tissue compartments (ZH-L16C vs L16B, and yes there is a difference and yes people argue about it), M-values, and the deep-stop controversy (Pyle stops reduce bubbles but increase slow-tissue on-gassing — nobody agrees on whether they help). You write your plan on a waterproof slate, hang it around your neck, and follow it exactly. Your computer cross-checks your plan. If they disagree, you follow the more conservative one. PODI's deco course uses Skip's personal Excel 97 spreadsheet. It does not account for repetitive dives. It does not account for altitude. It does not account for your SAC rate. It does not account for the fact that you are breathing helium — actually this is fine because we do not have helium. The spreadsheet does have a Word Art title that reads "DECOMPRESSION PLAN — SERIOUS BUSINESS" and a gradient background with the colours of the Australian flag. We believe this qualifies it as international standard software. The practical component involves a controlled ascent from 30 metres to a simulated deco stop at 6 metres. You hover for 15 minutes without a reference line. If you drift above 4 metres, you restart the clock. If you drift below 8, we consider that a "new deco obligation" and add 5 minutes. If you surface with less than 5 minutes of simulated deco remaining, you get back in and try again. You will be cold. You will be bored. You will understand why real tech divers are so meticulous about planning — because being wrong means doing this for real, except for real it is 30 minutes at 3 metres in 7°C water while your computer counts down from 47 and the boat drifts away from you. We call our version "decompression-adjacent training." Your certificate will not say "adjacent." It will say "Decompression Procedures Qualified." This is technically true. You qualified. You qualified in something.

Staged Cave Diving GOLD LINE? WE USE TWINE. CAVE FILLS? WE HAVE GARY'S COMPRESSOR.

Real staged cave diving uses goldline (a specific fluorescent yellow line that is the global cave-diving standard), jump spools and gap spools for navigating between permanent lines, certified cave fills from a bank system, and the rule of thirds so strict that you turn around at one-third of gas, not one-third of distance. The minimum training for full cave certification is usually several hundred cave dives over multiple years. We have done zero cave dives. We do not own goldline. We own mason's twine from the hardware store. It is white. It will disappear against the pipe walls immediately. You will navigate by feel. The rule of thirds is hard to enforce when none of your cylinders were filled to the same pressure by Gary's compressor. One tank has 200 bar. One has 170. One was filled last week and has been sitting in the sun. You will manage your thirds differently for each tank. You will not do this correctly. Your stage bottles are clipped to your hip D-rings with bolt snaps that Gary sourced from a bin labelled "mixed hardware — $5." They will work or they will not. We will find out underwater. If you emerge from the correct drainage outflow, you pass. If you emerge from a storm drain in front of a school, you will have a conversation with the authorities. We will not join. We will be in the truck with the engine running. Not because we are fleeing — because it is cold outside and the heater works.

What Our Grads Are Saying QUOTES COLLECTED BEFORE THE BENDS SET IN

We asked our graduates to describe their PODI Technical experience in their own words. These are those words, reproduced exactly as they were said, before the nausea started. Some names have been changed. Some stories have been shortened. One story was told to us through a chamber window. We included it anyway.