About a year before the trip, a friend of mine invited me to a “Great Lakes Wreck Tour”. The trip was a bit over 2 weeks long with 12 days of diving planned over 3 different areas. The boats had been booked 3 years in advance and only had 6 spots total. It involved [...]
mCCR versus eCCR When you look into purchasing or diving a closed-circuit rebreather (CCR), you will quickly encounter two primary designs. These are the manual closed-circuit rebreather (mCCR) and the electronic closed-circuit rebreather (eCCR). Both types of rebreathers use electronics to monitor your breathing loop. The fundamental difference between them is how they add [...]
Technical diving involves carrying extra cylinders like decos or stages. More cylinders do not equal more safer, and a common issue for technical divers, even today, is breathing an incorrect gas mixture and having hypoxia or hyperoxia. Deco cylinders are used on the ascent and contain higher oxygen concentrations to accelerate decompression speed. Stage [...]
Gas Blending When you transition into technical diving, learning how to blend your own breathing gases is a valuable skill. When I became a tech diver, learning to blend was a standard requirement because team members had to prepare their own gases. Today, technical fill stations in technical destinations are common, but relying solely [...]
Stage Diving When divers get full cave certified and start exploring passages that were previously off-limits involving complex navigation, they eventually hit a wall. Not a literal wall of rock, but a strict limit on penetration. Even with increased experience, comfort, and large capacity cylinders, like HP133s, you can only go so far on [...]
Tank Factors In technical diving, executing the rule of thirds or planning gas management is simple when everyone on the team swims with the exact same cylinders. If both you and your buddy carry identical doubles and start with equal pressure, you will turn the dive at the exact same pressure. However, this [...]
Helium Penalty Technical divers use helium to reduce gas density and narcosis. The "Helium Penalty" is the theoretical idea that because helium is a smaller, faster molecule than nitrogen, it requires deeper stops and longer decompression times. Modern research suggests this is theoretically incorrect. The famous shearwater article described this inaccuracy and quickly [...]
Important Gear Technical divers are usually meticulous - or, at least I hope they are. We should analyze and label every cylinder, research relevant topics, and reduce risk as much as is reasonable. Regulators should be taken care of and serviced routinely. The same goes for CCRs, lights, and exposure protection. The most important [...]
I don't want to do open circuit trimix, I'd rather get a CCR and save the money As the cost of trimix continues to rise, this conclusion continues to be more attractive. But - does the math check out? Probably not. Open circuit trimix still has a place in diving and is the correct [...]
Oxygen Toxicity Most divers know the NOAA Central Nervous System (CNS) oxygen exposure chart and the CNS tracker on your computer — telling you how long you can stay at a given partial pressure of oxygen. It’s a useful tool, but like most tables, it only tells part of the story. Oxygen toxicity [...]
