Confused about REC vs TEC for "certain" activities!

[Rhone Man]

If in doubt, I like to refer to the following helpful flow chart:

 

[danvolker]

The issue with the desiring to have no bubbles coming out to scare the fish....this is a huge money maker for the dive industry, pushing you into a CCR.

In the scenario of the OP, a person NOT wanting to move beyond recreational risks....I think this is a travesty.
Open circuit is much safer and easier to enjoy, and it "can" be silent/without noisy bubbles as well.

The best way would be to get a natural sponge and some pvc to fit into your 2nd stage exhaust ---capture the exhaust with the pvc, the pvc is filled with the sponge, and the sponge will need enough surface area to handle the volume of exhaust...it turns the big bubbles into micro bubbles, much like fiz.

Jack Kellon had something like this on the early predacessor to today's RB 80 rebreather....On the Odyssey and maybe on the BMD before it.
The 2nd stage was rear mouted, like the Vintage stuff you see on Sea Hunt..but this just makes it easier to keep the sponge out of your way.
As an engineering issue, this should be simple to accomplish...with the early Kellon designs, the burping of the Semi closed rebreather or even bypassing, caused only fiz, and zero sound.
This could be done for very little investment.
Of course, the dive industry would not like bubbleless diving to be possible without thousands of dollars in additional instruction, and thousands in new rebreather gear.
So if you want to make your bubbles silent, and do not want to be a "patsy" for the Dive Industry, then put some time in to playing with some sponge and pvc DO NOT BUY A REBREATHER JUST BECAUSE YOU THINK THIS IS THE ONLY WAY TO BE SILENT ENOUGH TO SEE THE FISH THAT SCARE EASILY.....

 

[flots am]

Hopefully someone can help alleviate my confusion and if I've been misinformed they can point that out.

The "line in the sand" for determining if you're doing a "technical" or "recreational" dive is: "Can you safely surface at any point during the dive with minimal risk?"

The last, fail-safe option for nearly any emergency you're likely to encounter on a recreational dive is "getting to the surface and staying there"

A technical dive is either a physical or virtual overhead environment, which means that you can't surface if something bad happens (there may be rock or a ship overhead, or you may have a significant decompression obligation). Either of these means that no matter what happens, you need to take care of it where you are, and OW training does not teach this.

I have no idea what PADI teaches for Ice Diving, but if you stray from the hole, it's definitely an overhead environment. They might consider the line and tender(s) to compensate for this, but the truth is that if there's any point where you can't "go up", OW training isn't enough. This is why you see cave/wreck/ice divers with so many tanks. Some may contain different mixes for different depths, but others are just for dealing with emergencies.

flots.

 

[markmantei]

If in doubt, I like to refer to the following helpful flow chart:

View attachment 117405

This is hilarious, probably because it's true. Trying to do the sell job right now that it doesn't need to be more dangerous and the education would be good none the less. The wife isn't buying it yet though.

 

[Dive-aholic]

Well there has been some good info so far but I'm not ready to jump in just yet. Could be a very long time if ever. Tec diving appears to demand alot of attention to detail and alot of respect, both of which I'm willing to give/do but not anytime soon. I'd love to go cave/cavern diving and ice/iceberg cavern diving but only if they are well within the limits. I think a cave at 40ft that went about 50-100 feet would be very cool but I'm not into staying great lengths of time or going 4500 ft from the entrance. Maybe I'm just cavalier or ignorant but I don't really think of SCUBA as an "Extreme" sport but I think doing a cave dive that long or really deep certainly is very extreme. Night diving is definitely getting more into the extreme end and I plan on doing that but as for the rest, for me, I'm just not sure yet if the risk is worth the reward.....

It's all a matter of perspective. I've done dives 7000' back into cave systems and don't see that as extreme. With the proper training, equipment, and planning such a dive can be done quite safely. But I also don't find night diving as extreme. To me, extreme is jumping out of an airplane!

So what is the actual difference then? Is it considered a cavern because you are still in the light zone whereas cave is pitch black? Or is there a size requirement? If I came across a big open space the size of "one" movie theater would you consider that a cavern whereas the exit hallway would be a cave? To be honest, they both pretty much look the same to me and in either case you're still under an overhead. Where is the differentiation? What dictates the shift and how is either one really different from the other?

The cavern zone is limited to 200 linear feet from the surface. This means if you're 50' deep you can only penetrate 150' into the overhead. However, you must also remain in the daylight zone of the overhead. In that 50' deep cavern if the daylight cannot be seen 100' into the overhead then it's no longer a cavern.

 

[waterpirate]

This is hilarious, probably because it's true. Trying to do the sell job right now that it doesn't need to be more dangerous and the education would be good none the less. The wife isn't buying it yet though.

My wife "bought it" after I bought the life insurance that insured she would never have to work again upon my demise!
Eric

 

[Bob DBF]

Learn to dive vintage Double Hose and put your bubbles behind you, the fish are not as annoyed and you don't have to shell out the big bucks for a rebreather.

The confusion with Rec and Tech is because Tech is still recreational diving only at a more advanced level. The term Technical Diving only surfaced in the late '90's and prior to that it was all recreational diving with very advanced levels of diving such as Deep, Wreck, Cave, and so on.



Bob
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I may be old, but I’m not dead yet.

 

[geoff w]

Isn't the boundary between tec and rec a moving target? My wife will do a deep dive on a wreck in a dry suit and backplate/wing breathing nitrox and exploring the wreck with a scooter. I get the feeling that years ago this would be considered outside the realm of purely recreational diving; now it's all mainstream recreational diving. Trimix is becoming less exotic than before, and I'm sure PADI will have a trimix specialty at some point, just like they're starting CCR and sidemount recreational specialties. There are recreational dive trips into caves and caverns in some areas of the world, just like there are deco recreational tourist deep dives, like the Coolidge in Vanuatu. A lot of it seems to be a matter of technology advances, risk assessment and management, and putting more advanced activities within the realm of recreational divers - probably a bit of an over simplification, but certainly these factors all come in to play

 

[Jim Lapenta]

Hmmm. Taking a mechanical device to exist in an environment that is normally hostile to human life. One that if not respected will kill you very quickly in some VERY nasty ways. I'd call that extreme.

 

[fisheater]

PADI already has a trimix/tech program.


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