Issue 12 Enter the Dragon: An Armchair Diver's Guide to Technical Dive Courses from the Archives of the Tanked Up Magazine

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23 November 2024

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	ISSUE 12 ARCHIVE - ENTER THE DRAGON: AN ARMCHAIR DIVER'S GUIDE TO TECHNICAL DIVE COURSES Paulo Vincenzo Toomer Continuing from the last edition – you all have the state-of-the-art kit money can buy. It's all boxed up and ready to go. Granny has been allowed to move back into the house, but your partner does not want you using any of the tech kit you have just purchased. Number one, it's deep and dark down there on a tech dive and number two, something will probably eat you. Well my answer is simple, get some proper technical diver training and second "Come dive the azure waters of Malta: walls, caves and deep wrecks, trimix, CCR... and you won't get eaten".
	So, the question is, how do you start? We have discussed training agencies and kit setup in the previous issues. Now, let's explore what an entry level programme actually teaches you. Before I go on, I would like to say that this article is NOT definitive and does not indicate all the skills from every agency. This is just a generalisation. The aim of an entry-level technical programme is to allow the diver to safely dive using twinset and a single stage decompression gas. To train the diver to safely plan and execute minimal decompression dives using air, nitrox, oxygen and sometimes (if you are lucky) trimix. Yeah man... TRIMIX! The training agencies IANTD, TDI and PADI have Trimix on their first level tech programmes. I am not really discussing GUE in this article, as their entry-level programme that is called Fundamentals is NOT a technical decompression programme. It and IANTD's Essentials programme are team building, equipment-orientated courses that focus on training a diver to become proficient in all the basic tech skills but also advanced buoyancy, propulsion techniques, trim and drag.
	Let's break it into sessions; class, confined or limited open water and open water. Class Generally speaking, academically you will look at: Equipment, what you need to use and why. The safe use of oxygen, including tracking oxygen exposures (this section is incredibly important due to the nature of oxygen when used at pressure). Gas laws and principles which enable you to select safe gasses for the dive. Inert Gas Narcosis and the use of helium gives you an understanding of what actually happens to you when you have narcosis and also why it is extremely unsafe as a decompression diver to dive under the narcotic effect.
Decompression covers the understanding of decompression tables, both computerised and in table format. Some training agencies cover deco ratio diving which allows you to compute your decompression schedule on the fly, while you are on the dive. Very clever stuff. Within this section we look at decompression sickness, lung overexpansion injuries, bubble mechanics, bubble formation and effective decompression schedules. Finally, we look at Dive Planning, putting everything together so we have a safe plan in terms of length and quality of decompression, oxygen exposures, failed gas plans and gas consumption rates, which tell us if we have enough gas to actually do the dive. All agencies have an exam and some have knowledge reviews. Confined Water Skill Circuit Now this is where the fun really starts. All the instructor's and training agency's have slightly different skill circuits, so I will cover only the popular skills. First off is, of course, the shutdown drill or drills. I break my intro shut down drills into four different shutdowns: First off, I do a primary (long hose) second stage free flow, where the diver simply switches to the backup regulator, and turns off the offending, in this case the right hand side, valve; Then we fail the left hand side. This is done in exactly the same way, but without the regulator switch. The next two drills are for a failure behind the diver's head, so a first stage, manifold or cylinder neck O-Ring failure: First close the isolator valve on the manifold, then work out which side is freeflowing. This can be done by feeling behind your head for the leak; you will certainly be able to work it out! Or you can pick up your gauge, which is on the left hand post. If the needle is dropping then the leak is from the left, if it is static, the leak is coming from the right. If it is the right valve, the diver switches to the backup regulator and closes the right valve. Then we need to see if there is any gas still leaking. This can be done as per the technique mentioned above. If there is still gas leaking, the manifold must be left closed. If there are no leaks the manifold can be re-opened. Executing the drill for the left hand side is exactly the same, but without the switch to the backup regulator. We also have gas sharing drills. These drills are obviously incredibly important in order to keep the team safe in the event of a gas problem. The primary aim for open ocean divers, not cave or wreck divers, is to be able to effectively hand over the primary regulator to a team mate that has no gas. The donor hands over the primary long hose regulator and switches to the backup regulator. The two divers then free all of the hoses so that both divers have some space, let's face it, a twinset and stage take up a fair bit of room. They begin their ascent and practice holding some decompression stops. Some agencies ask for this to be done without a mask, which makes for great fun and we also get to practice retrieval of the backup mask. Some instructors will teach these drills as per cave protocols, which, in all honesty, is no bad thing.
We then have stage removal and replacement, both on the surface and underwater. Some instructors also do stage swapping between divers; again more fun and the team really have to get their buoyancy and positioning perfect. Then we move on to Surface Marker Buoy drills. Here the diver gets taught the proper technique for sending up a 'bag' safely using a spool or reel. This is probably the hardest of all the drills to get right. Much entertainment to be had as the instructor watches bags and divers flailing about all over the show on the first attempt. Finally we have the decompression gas switch drill where you are taught to safely identify, turn on and switch, with a team mate's approval, to a high oxygen decompression gas. This skill is so very important as switching at too great a depth for a particular gas can cause you great harm, switching too late or too shallow can damage your decompression schedule. There are loads of other drills that can be and are put into the programme, but these (I think) I can safely say, are the fundamental skills of all technical courses. Open Water Dives All agencies have a different number of dives to get to the certifying dive and they are based on what the training agency sees as safe. On the training dives you will be challenged with the skills you learned in the confined water in a 'real world' way. Your instructor will do the drills in an environment where you are not put in any danger. These dives also take you through simulated decompression to full accelerated decompression dives. You will apply your knowledge and skills to plan and execute safe dives to the instructor's and training agency's standards. Thank you for taking the time to read this. As you can see, it's easy peasy to become a techie. No mystery or magic, just good training, knowledge, attitude and skills needed for your entry into our wonderful tech world. I hope this has removed some of the worries you may have regarding coming over to the dark side. All opinions in this article are mine and are not meant to upset any training agency or instructor. You can email Auntie Toomer with any of your dive queries and you might also like to check out The Diving Matrix.
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