Next step for longer bottom times on deep dives?

[Wibble]

Well, dive 36

Or take a stage of 80% and stay as long as you like.

 

[Marie13]

Or take a stage of 80% and stay as long as you like.

OP would still need to get minimum Adv Nitrox cert to have access to 80%. As far as I can tell, no way around getting an advanced cert or two.

 

[doctormike]

Rebreather.

Large entry cost in terms of finance and commitment -- think motorcycle. Once over that, it's amazing, cheap to run and flexible.

Failing that it's a twinset, stages and learning decompression procedures.

Other agencies factor in your future, not PADI.

I love my CCR, has really revitalized my interest in diving. I use it for pretty much every dive other than very shallow shore dives where I don't feel like setting it all up for macro work in 5 feet of water.

But you have to be doing a good bit of OC trimix before buying a rebreather saves you money. Just considering consumables alone (sorb, cells and maintenance), it's really not cheaper for the vast majority of divers.

Yes, there are big deco advantages, but for the kind of diving the OP is doing, that would be primarily in shallower dives where a fixed PPO2 of 1.3 will give you a lot longer NDL than any reasonable OC mix. For example, if you are doing a dive to 60 feet (2.8 ATA), you would have to be diving EAN 46 to get the same NDL as a CCR. With the OP diving a relatively square profile to 100 feet (4 ATA) on EAN 32, they would have similar NDLs on OC.

For what the OP posted, I don't see why anyone would be suggesting a CCR. I think that they are great, and while they add risks they also remove other risks, and that's a whole different argument. But given the limits of what they are asking, OC tech training seems to be a better use of time, money and resources for this particular situation.

 

[doctormike]

OP would still need to get minimum Adv Nitrox cert to have access to 80%. As far as I can tell, no way around getting an advanced cert or two.

Not just access to the gas.

If you are taking 80% to extend your bottom time, that's not a "stage", that's a deco bottle for accelerated decompression. And of course, if you are planning to "stay as long as you like", you had better have enough back gas to complete your lost gas plan if for whatever reason you lose access to that deco bottle.

 

[flymolo]

I see guys say that a lot but isn't that mentality a little bit of a hold over from the days where CCRs were a lot less reliable, a lot higher risk, and the only people using them were doing exploration dives?

In my neck of the woods, I see CCR guys doing rec profiles and basic tec profiles (40-50m with 30-40min deco) all the time. Of course those dives could be done on OC very easily. I see guys diving CCRs on 15m/60 minute rec dives a lot, but they need to be doing those dives with their CCR so they can maintain proficiency so that when they go do a 75m dive, their skills are sharp.

I'm going CCR very soon, and the primary driver for that is Helium, but I fully intend to dive my rebreather on most of my rec dives as well to get hours on the unit, and avoid maintaining unnecessary sets of doubles and regs that I won't need because I'll have a CCR. And even on rec dives, 5lb of sorb is cheaper than a doubles nitrox fill ($35) so it will save me a lot in the long run.

I think it's useful to rack up hours on ccr initially, but there comes a point where it becomes unnecessary to take the ccr on every dive, especially when oc will work just fine. There are other considerations too, like keeping your oc skills sharp, or avoiding "mixed-team" diving. Plus, sometimes it can be refreshing to just screw some regulators onto some tanks and go open circuit diving, without the need to perform a whole ccr build/teardown procedure.

Also, again, even the "safest ccr" still presents risks not present on oc.

 

[doctormike]

I see guys say that a lot but isn't that mentality a little bit of a hold over from the days where CCRs were a lot less reliable, a lot higher risk, and the only people using them were doing exploration dives?

In my neck of the woods, I see CCR guys doing rec profiles and basic tec profiles (40-50m with 30-40min deco) all the time. Of course those dives could be done on OC very easily. I see guys diving CCRs on 15m/60 minute rec dives a lot, but they need to be doing those dives with their CCR so they can maintain proficiency so that when they go do a 75m dive, their skills are sharp.

I'm going CCR very soon, and the primary driver for that is Helium, but I fully intend to dive my rebreather on most of my rec dives as well to get hours on the unit, and avoid maintaining unnecessary sets of doubles and regs that I won't need because I'll have a CCR. And even on rec dives, 5lb of sorb is cheaper than a doubles nitrox fill ($35) so it will save me a lot in the long run.

5 lbs is the low end of scrubber size - but figure about $20 for that sorb. Plus you will need 100% O2 fills, and $300 a year for sensors. Unless you are doing a lot of OC trimix, it will take you a long time to get your money back!

But congratulations on going to CCR... and I would say that you should dive it on every dive (OK, maybe not a quick last minute shore dive to 10 feet). Racking up hours is really important, and even experienced CCR divers should keep their skills up. I really prefer not going back and forth - better for muscle memory to stick with the CCR. Plus, it's a lot more fun to dive... who want's to go back to all of that noise?

 

[flymolo]

5 lbs is the low end of scrubber size - but figure about $20 for that sorb. Plus you will need 100% O2 fills, and $300 a year for sensors. Unless you are doing a lot of OC trimix, it will take you a long time to get your money back!

But congratulations on going to CCR... and I would say that you should dive it on every dive (OK, maybe not a quick last minute shore dive to 10 feet). Racking up hours is really important, and even experienced CCR divers should keep their skills up. I really prefer not going back and forth - better for muscle memory to stick with the CCR. Plus, it's a lot more fun to dive... who want's to go back to all of that noise?

Back in December I dove ccr almost every day for a month. By the end of the month I was feeling pretty tired one morning, so I decided to skip building the ccr and went on a shallow cave dive on oc, and I was surprised at how much my oc skills had deteriorated. It took me several hours to start getting back into the oc groove, not to mention I gave my friends some pretty good laughs watching me flail around in the process. During the month of February i dove oc almost exclusively, and only took the ccr on longer (4+ hour) dives. It was really nice to not add an hour and a half or so of setup/breakdown time to each day of diving, especially when diving multiple times a week. Ultimately I've come to the conclusion that it's valuable to be able to choose the right tool for the dive, which means keeping skills sharp on both oc and ccr. However, I will say that I dove ccr exclusively for the first hundred hours or so, and would recommend the same to a new ccr diver.

 

[100days-a-year]

Ya'll do realize we are in an echo chamber?

Probably less than .1% of the actual technical certified divers in the world will ever even make it to this forum much less to see your arguments for or against either gas choice.
Of the divers making these dives most will never consider HE and many won't even know it's a possibility.
The reality is that for a recreational hobby, the vast majority are not interested in spending the time and money to get the certification, not interested in spending the money on the gear and gasses, not interested in the extra gear and complexity and will dive air or nitrox whether a few internet Karens like it or not.

There is a post in Basic detailing the decline in participation in scuba in part due to younger generations having a different view on risk and investment of time, money and energy vs. reward. Figure how that will affect the future of diving. We will likely be dinosaurs in another generation because we actually go outdoors.

I disregard name droppers most of the time, but I'm home recovering from Covid-19 and pneumonia and have some free time.

For the OP, I know a lot of divers in your neighborhood and a few look for divers occasionally and they hit all those wrecks on private boats. If you're interested, I'll see if I can get ya'll hooked up. There are also some groups on FB that get some activity.

 

[ginti]

....

Accepting scientific results is exactly the opposite of being in an echo chamber.

That said, your arguments about price and rewards are more than reasonable and are the only reasons why I do not expect any diver to use helium, even if that is the optimal gas according to the pieces of evidence we have today.

 

[flymolo]

Accepting scientific results is exactly the opposite of being in an echo chamber.

That said, your arguments about price and rewards are more than reasonable and are the only reasons why I do not expect any diver to use helium, even if that is the optimal gas according to the pieces of evidence we have today.

I'm surprised nobody has mentioned the fact that diving helium actually feels better. You see more of your surroundings, you have better awareness, and you remember more of the dive afterwards.