I’m frequently asked if you need a rebreather for technical diving or if you can still use open circuit. It’s a tough question, and I don’t have a definitive answer. I can give you some things to consider that may lead you to the answer that works best for you.
Where I’m coming from
Here’s a bit of my background for context. I got certified a long time ago and had been diving for about 20 years when tech diving was “invented”. Back then (mid-1990s), tech diving meant diving with nitrox, diving deeper than 130’, or decompression diving. I got into tech diving because I wanted to learn how to do decompression dives to expand my wreck diving. I became a tech diving instructor in 2000. I’ve been a technical diver since the 90s and have been teaching tech diving for 25 years. Most of those dives have been open circuit. I did my first CCR class in 2019 and have been diving a rebreather pretty much exclusively since then.
Pros and cons
When it comes to tech diving, the choice between open circuit and closed circuit depends on your diving goals. You’ve probably heard about the benefits of CCR diving: longer gas supply, no bubbles, warmer and moister gas, optimized decompression, and they are lighter than double tanks. But you’ve also heard about the drawbacks: CCRs are pricey, have more parts and pieces (higher likelihood of failure), and they require more maintenance. All of these are true. Our goal is to maximize the benefits while minimizing the risks. Rebreathers are no longer experimental or cutting edge technology. They’ve been around awhile now and rebreather design is pretty solid. Equipment failure in a well-maintained rebreather is uncommon. We can do a pretty good job of minimizing the risks by following established safety protocols. Another factor to consider is where you’ll be diving and how often. If you only dive a few times a year, you might not need a CCR. Rebreather diving demands lots of practice to become proficient. Active divers will become good at diving a rebreather and reap the most rewards.
Geographical considerations
Think about where you’ll be diving. CCRs aren’t easy to take on a plane. It can be done, but it’s more of a hassle than just throwing some open-circuit gear in a suitcase. You also need to make sure your destination is rebreather-friendly. That means they can supply absorbent, oxygen fills, bail-out tanks, and other gasses. If you mostly dive locally, CCR actually has some great advantages over open circuit. I dive in many different locations around the Great Lakes. Almost all of them are remote and have no gas fills available. You have to bring everything you’ll need. When my dive buddy and I would do a 3 or 4-day trip on open circuit, we pulled a trailer full of diving gear. A 4-day diving trip with my buddy meant taking 8 sets of doubles and 16 deco bottles.
And then there’s the cost
There is no doubt rebreathers are costly, but let me provide some perspective. If you had to buy all your open-circuit tech gear brand new, it would cost about the same as a rebreather. And let’s not forget about the cost of gas fills. For my 4-day dive trip, I can either pay to fill 4 sets of doubles and 8 deco bottles, or a few small rebreather tanks. If you’re diving trimix, the cost savings is huge. The main difference in cost as I see it is that you have to pay a big chunk upfront when you buy a rebreather. With open circuit equipment, the cost might be more spread out because you can build your equipment collection gradually.
The other cost
Another “cost” many divers buying a rebreather don’t think about is the time commitment required. Rebreathers require a lot of practice. If you decide to get one, you have to know going in that you absolutely must dive it a lot to build your proficiency. The main reason I see for people getting out of rebreather diving is the lack of time to dive. A lot of the ads for used rebreathers are from people who bought it, took the class, and then only used it a few times. They quickly figured out how much time and effort they had to put in to rebreather diving.
Temperament
Lastly, there’s the matter of temperament. Rebreather diving isn’t for everyone. Rebreathers demand discipline and patience. You have to be diligent and careful when preparing your CCR. You have to follow the checklist to the letter. If you find any faults, you must take the time to find the problem and correct it. After the dive, you have to clean and sanitize the unit thoroughly. There’s no room for shortcuts, no skipping steps, and no putting it off until later. If you don’t have the self-discipline to do that, open circuit might be a better choice. Open circuit equipment is much simpler than a CCR, so it has fewer failure points and is more forgiving. If you get home after diving and put your open circuit equipment in the garage and leave it for a few days, there’s no real harm done. You cannot do that with a rebreather.
Wrap up
I know that’s a lot to take in, but hopefully these thoughts will help you make a decision that works for you. I switched to CCR 6 years ago, and I don’t regret it one bit. My rebreather is great for my Great Lakes diving, and it’s not too inconvenient to take on a plane. Whether you choose open circuit or closed circuit equipment, there’s a lot of fun and adventure to be had underwater!