If you’re a recreational diver who’s decided to take your first technical diving course, what should you expect to learn?

So, you’ve decided to see what the world of technical diving is all about and enroll in a foundation class. Wise decision. But what’s covered during your first technical diving course? What will you gain from the experience, and what will you learn? Here’s a little insight into both what to expect, and what not to expect from your first technical diving course.

Why take a technical diving course?

There are many reasons to become a technical diver. You can dive deeper and stay down for longer, or both. You may wish to become a more skilled diver in general and increase your knowledge of dive theory, or decrease your reliance on a buddy. Perhaps you simply want to challenge yourself, or pursue cave or wreck-penetration diving. It’s entirely possible though that none of this appeals to you, and you simply want more fish-watching time on your favorite shallow reef. These are all great reasons for starting tec training. So where do you begin?

If we leave rebreather diving for another article and use Technical Diving International (TDI) as an example agency, there are two main options: you can enroll in either the technical sidemount class or intro to technical diving course. Both courses provide similar information, but with a different approach and emphasis to the equipment set up.

What you will learn?

In a sidemount course, you will learn to set up and dive with two cylinders at your side. For intro to tech, you will get to know how a twinset works (two cylinders on your back, joined together with an isolation manifold). There are numerous reasons for using either method, which each course will outline.

Common to both methods is a redundant gas supply and ensuring that you have a backup of almost everything — torches, cutting devices, bottom-timing devices, etc. Pretty much the only thing tech divers don’t carry two of is pairs of fins. But it’s not just a question of carrying backup gear; you must know when and where to use it. A knife, for example, is useful for many things, but what if your tank valve becomes entangled in some fishing line in bad visibility? Do you really want to use a knife near your hoses and behind your head, where you can’t see what you’re doing? Maybe a Z-knife is better for that job.

Good tech divers carry appropriate items stowed for easy accessibility, but — and this is key — without turning into an over-encumbered Christmas tree. You will learn to carry only what you need for a given dive. This is for reasons of simplicity, streamlining, and minimizing task-loading. Tech courses will cover all these topics.

Having a technical diving mindset

Having a technical diving mindset means two things. First, as you progress, you will begin to understand that you’ll be engaging in increasingly risky diving activities. There are consequences to diving deeper and longer, so you must approach such dives with the seriousness that they deserve. Second, since safety is the top priority, you must diligently manage those increased risks. This involves looking at potential hazards associated with, for example, entering a cave or going into decompression. You must either eliminate the risk or reduce it to an acceptable level.

This task is all-encompassing. It includes choosing the correct equipment for the dive at hand, maintaining it, and checking it before and after diving. You must become highly competent at diving fundamentals such as buoyancy, finning techniques, guideline use, and emergency procedures, practicing them regularly. Having a technical diving mindset also includes proper dive planning, and a thorough post-dive debrief. A foundation course will introduce all these concepts.

Dive planning and gas management

Comprehensive and effective dive planning begins long before you don your drysuit or wetsuit. It includes consideration of environmental factors, such as weather and tides, team roles and responsibilities, thermal considerations and logistics. You must also consider the potential side effects of different gases, such as narcosis, hypoxia, hypercapnia and oxygen toxicity. You’ll begin to use dive-planning software to map out dives, and learn about decompression stress and how to reduce it with an appropriate dive profile.

When it comes to gas management, you’ll obviously have more gas available in double tanks. But when you know you will be going into decompression, and therefore unable to ascend directly to the surface, you must figure out exactly how much gas you’ll go through during a dive. There are two ways to approach this:  planning the dive first and then and then determining how much gas you’ll need to execute it, or starting with a fixed amount of gas and planning a dive within those limits.

Either way, during the introductory course, you will learn to calculate how much you breathe per minute, and how much gas you will go through at each stage of the dive. In subsequent courses, you will learn to add various contingency gases in case something goes wrong, and track other limiting factors such as CNS exposure.

Diving procedures

Planning a dive is one thing, but completing it properly requires skill that can only come from lots of practice and quality training. Controlled descents, good trim, team positioning, awareness, communication, and varying ascent speeds are all keys to a successful technical dive. An introductory technical course will lay out these important foundations in detail.

Lots of supervised time in the water is also key. Although technical dives are commonly 90 minutes, they’ll fly by as you learn to communicate with one hand, practice alternate propulsion methods and back-finning, and learn to deploy a DSMB from depth and wind it up as you ascend.

In each course, you’ll learn how to manage your gas in either a twinset or in sidemount. You’ll learn how to shut down valves in case of a gas loss, and then how to end your dive safely and efficiently. Courses cover other emergency skills as well, such as out-of-gas using the long hose, switching to a back-up mask, a malfunctioning Low Pressure Inflator (LPI), and free-flowing regulators.

What you won’t learn

Reading all of this, it can be easy to feel a little intimidated by the scope of technical diving training. But you will find that everything is incremental. If you have good buoyancy and want to learn, you will be surprised by what you pick up over only a few days of supervised training. You should emerge from a course with a solid foundation of knowledge and practical skills that you can build upon.

Things that you won’t take away from the course include any kind of decompression training, or any kind of penetration-dive training, such as entering caverns, caves or wrecks. Also, don’t expect reams and reams of theory. While you will learn some, the courses focus on becoming familiar with the equipment and procedures and logging plenty of in-water time to become competent with it all.

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