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 choice for most divers.

The numbers are not the only, or most important part. A common misconception is that CCRs are safer or better than open circuit. This is not true. Read more here.

Before looking at the numbers, let’s set a few boundaries.

  1. You’re a deco diver.
  2. You have experience deco diving.
  3. You want to do dives between 150ft-200ft

To do trimix on open circuit you need:

  1. Trimix class
  2. Go see the cool stuff at 150ft+

To get a CCR and dive to those depths you need:

  1. Buy a CCR and do the 150ft class.
  2. Get 50+dives of experience
  3. Do the 200ft CCR class*
  4. Go see the cool stuff at 150ft+

*Why can’t you go straight to 200ft on the CCR as an experienced deco diver? Rebreathers are a new tool. You need to build muscle memory and competence diving the unit at shallower depths before have a reasonable ability to handle emergency situations deeper.

If you’re not a deco diver, then it’s about the same parameters because you path would need

  1. CCR 100ft no deco class
  2. Experience
  3. CCR 150ft deco class
  4. Experience
  5. Do the 200ft CCR class
  6. Go see the cool stuff at 150ft+

This assumes:

  • $4/cuft of trimix – my local shop cost
  • 160cuft of trimix for each dive
  • Boat diving
  • 50 dives to gain proficiency for 200ft CCR dives (50 is minimum standard)

It’s missing:

  • Regs, cylinders and other gear we need. I left this out because each path requires more cylinders and regulators.
  • Diluent cost per dive for CCR.
  • Annual CCR service
  • CCR consumables like cells (~$300/year)

Takeaways

  • The per-dive cost of CCR is much lower, but the initial investment is much higher.
  • It takes >60 trimix dives to have a financial benefit of diving the CCR.

60 dives doesn’t seem like much, but we need to put that into perspective. If we are doing these dives a few times a week, then the CCR has a clear financial benefit. There’s still the additional risks of CCRs to consider, but from a money perspective, it makes sense.

Weekly 200ft dives is not a common frequency. Most trimix divers I know are doing <10 trimix dives a year, and a few dozen shallower dives. If you’re currently doing deco dives weekly, then you’ll still be doing air/nitrox deco dives to shallower wrecks after the trimix certification. Even if we do 24 200ft dives a year, it takes 2.5 years for the investment of the CCR to make sense.

So, why is it so prevalent to want a CCR to “save money” on trimix? Rebreathers are cool, that’s really what it boils down to.

Opportunity Cost

While we shouldn’t be in a rush to get to our dream dive, life changes. Gaining proficiency on CCR takes time, typically more than the 50 dive minimum required by standards. If there’s a shipwreck we want to see, why wait another 1-2 years to gain the proficiency on the CCR? I’ve seen many motivated divers move, have kids, or change jobs and never go to the places they wanted to. If they didn’t buy the CCR, they would’ve been able to.

Similarly, if we have $10k burning a hole in our pocket, we can travel and hit cool places instead of tying that capital up on a new unit.

Final Notes

Buying a CCR to save money on occasional trimix dives can be like buying a private airplane to save on airline tickets.

I am a rebreather instructor, I’m incentivized to sell CCRs, and I like diving my CCR. The numbers are for a specific scenario that frequently arises. There are other reasons to use CCRs and other factors to consider. Saving money on trimix isn’t one of them unless we’re going to dive deep a lot. The utility of hub-based navigation in cave diving, frequent deep dives, remote projects, and other logistically challenging OC situations are where the CCR shines.