Dumb question, but... how deep can you go?

[Cthippo]

I ask this as a rec diver with no strong interest in going CCR. I've been working on my Puget Sound wreck database and have most of the recreationally accessible ones mapped out, but there are some monsters of the deep, including some big unknowns and I'm just wondering which ones are theoretically accessible to CCR divers and which would require a ROV to explore.

So what is the maximum reasomabke depth for recreational CCR use?

 

[Rayk]

Recently a diver made it to 312 meters.

308 meters in a cave

 

[Raphus]

I would say realistically, with a lot of training and still a moderate risk assessment, you can reach 100-150m.
Over 150m is of course possible, but in my opinion the risk increases exponentially. So somewhere in this area is the border for "normal" CCR dives.

If you go deeper (arguably even way shallower with decent bottom time) You need habits, bailout ccrs and a great team to support each other.

 

[BoltSnap]

Do CCR's need to be modified in anyway to go deeper than 100m or are there special ccr's that are rated to more than 100m? The specs of all ccrs I have seen state that their max depth is 100m, I haven't seen any that say deeper (that I have seen).

 

[Angelo Farina]

Do CCR's need to be modified in anyway to go deeper than 100m or are there special ccr's that are rated to more than 100m? The specs of all ccrs I have seen state that their max depth is 100m, I haven't seen any that say deeper (that I have seen).

Some CCRs have a "blocked" (not compensated for ambient pressure) 1st stage providing oxygen at fixed absolute pressure, which results in constant flow into the loop.
The IP of this blocked 1st stage is usually set just above 10 bars, hence the max depth of 100m.
of course these units need to be modified for going deeper.
But the real problem is the gas density and viscosity, which makes breathing with a CC rebreather very hard below 100m.

 

[MidOH]

Saturation diving can go deeper, and would be the next step after rebreathers 300-ish limit. Down to 2300 feet.

 

[ofg-1]

How deep can you go? Depends, do you want to be able to come back up?

 

[BoltSnap]

How deep can you go? Depends, do you want to be able to come back up?

Can you talk "apples and oranges" and answer the OP's question please?

 

[PfcAJ]

Somewhere around 500’ seems to be practical stopping point. There are instances of going deeper, but the risks and complications really skyrocket much past 4-500’.

Gas density is huge. HPNS becomes a factor. Not to mention the deco obligations one incurs really gets out of hand. There’s thermal, hydration, and nutrition issues to contend with on long dives.

In extreme cases, people are using experimental gases like hydrogen to help with some of those above factors, but this obviously has its own set of considerations.

 

[evandroairton]

Do CCR's need to be modified in anyway to go deeper than 100m or are there special ccr's that are rated to more than 100m? The specs of all ccrs I have seen state that their max depth is 100m, I haven't seen any that say deeper (that I have seen).

Indeed, i don't recall any factory stating deeper than 100m, and so goes most of Trimix certifications. But even the IP fixed MCCR can manage beyond (stronger springs with higher IP, open ADV on bottom mix, and other tricks), but, as sayed, deeper = more inherent dangers. It's up to individual risk acceptance