No Drop Bottles for 30M+

[Blackcrusader]

I guess a lot of people would just call that "light deco" or something and treat it as a rec dive. I didn't mean to make such a fine distinction.

I've done dives on air where the deco multi level stops are totaling 35 - 45 minutes. I'm not sure if you call that light deco. In BSAC sports diving recreational dives are DECO planned on air back when I did my BSAC courses. I think technical diving is where you get to mixed gas deco dives like the GUE dives requiring the use of helium. The TDI Advanced Nitrox by itself recreational but the combined Advanced Nitrox and decompression course I guess some would call that technical diving as you need to do gas planning and generally that requires two tanks. Is diving with twin side mounts on air technical? I see divers in Asia with twins doing air or nitrox 32% - 40% dives staying within NDL doing recreational padi dives with them.

Lets say a Nitrox 32% diver does a 30m dive rock bottom for 40 minutes, that can be done on a single tank safely. You can stay at 30m can call the dive before you get to NDL or stay to 40 minutes then ascend and do your deco stop for 12 minutes at the safety stop depth ( on my settings on my Perdix FG 45/95. For me that is just a deco dive on nitrox. Is that technical? Being trained with BSAC deco on air the only difference is nitrox gives you much shorter deco obligations. Now if you are saying the deco is a soft overhead therefor technical then what about going into caves and shipwrecks where there are overheads and people do them on a single tank.

I would surmise that the TDI Advanced with deco compression course verges on being technical. Just my opinion I am not sure there is any hard line drawn for this. The defining from recreational to technical can get blurred. IF you only ever did padi which says do not exceed NDL or bad things happen then you might consider deco dives technical. II have a good friend who was a PADI instructor and she would always tell me hey you push the NDL too much other OW AOW divers on more conservative settings asked why I am staying deeper for longer on air as they would be past NDL already. Finally she did a side mount deco course last year. She said it still rattles her cage about going into deco as she is teaching all her students not to lol. Her mindset with padi is do not exceed or go to less than 5 minutes of NDL. For padi student safety this is fine.

 

[Blackcrusader]

I am fairly certain that in SSI deep diver training that the instructor has to carry (not leave hung) an alternate independent air source. The reason recreation diving is defined as being restricted to 35 or 40 m is because you can ascend to the surface from those depths without a stop, or having run out of air if you have to. It wont necessarily cause DCI but increases the risk and it would be advisable to breathe oxygen and take the rest of the day off diving is you have had to make such an ascent.

You can do dives much deeper on air and not exceed NDL and ascend to the surface as well. 40m is not the max depth on air for recreational for some agencies. I posted the 45m dive I did on air in this thread.

 

[beldridg]

AFAIK, there is no official definition of the term "technical diving." It does tend to depend upon the certification agency.

There is a tongue-in-cheek definition of "technical divers solve problems under water and recreational divers solve problems on the surface." I think that actually describes a potential definition.

I tend to think a technical dive involves either:

(a) A ceiling whereby you can't do a free ascent to the surface.

That could be a "hard" ceiling like a cave or wreck or a "soft" ceiling like a deco obligation. Either way, you cannot just go straight to the surface in the event of a problem and this inherently requires more gas planning.

AND/OR

(b) Trimix or a Nitrox mix more than 40%

It isn't always true, but if you are diving with (b) then you are probably into the territory of (a).

- brett

 

[Coztick]

AFAIK, there is no official definition of the term "technical diving." It does tend to depend upon the certification agency.

There is a tongue-in-cheek definition of "technical divers solve problems under water and recreational divers solve problems on the surface." I think that actually describes a potential definition.

I tend to think a technical dive involves either:

(a) A ceiling whereby you can't do a free ascent to the surface.

That could be a "hard" ceiling like a cave or wreck or a "soft" ceiling like a deco obligation. Either way, you cannot just go straight to the surface in the event of a problem and this inherently requires more gas planning.

AND/OR

(b) Trimix or a Nitrox mix more than 40%

It isn't always true, but if you are diving with (b) then you are probably into the territory of (a).

- brett

I think it's all fun and games, (rec.)
until you're not allowed to surface! (Tech)

 

[Blackcrusader]

AFAIK, there is no official definition of the term "technical diving." It does tend to depend upon the certification agency. There is a tongue-in-cheek definition of "technical divers solve problems under water and recreational divers solve problems on the surface." I think that actually describes a potential definition.

I tend to think a technical dive involves either: (a) A ceiling whereby you can't do a free ascent to the surface.
That could be a "hard" ceiling like a cave or wreck or a "soft" ceiling like a deco obligation. Either way, you cannot just go straight to the surface in the event of a problem and this inherently requires more gas planning.

AND/OR

(b) Trimix or a Nitrox mix more than 40%
It isn't always true, but if you are diving with (b) then you are probably into the territory of (a).
- brett

This lass solved her slipped tank underwater. Now I would have switched to my longer secondary but is she now a technical diver? lol

 

[Blackcrusader]

I think it's all fun and games, (rec.) until you're not allowed to surface! (Tech)

That's a fair point. Funny thing though is that some people calling themselves "technical divers" will go on about how my BSAC Sports diving doing deco dives on air is not technical diving as it's not mixed gases lol. The overhead seems to have slipped their minds lol.

 

[Jackie Treehorn]

I believe I recall seeing the hang tank in Morehead City, as well as Utila. I can see the argument against it being the possibility of emboldening divers to run their air down lower than they otherwise would have.

Yeah. Olympus in Morehead drops a hooka'd second stage off the stern that is zip tied to a chain. The tank stays on deck.

Roatan aggressor does it as well.

 

[boulderjohn]

This lass solved her slipped tank underwater. Now I would have switched to my longer secondary but is she now a technical diver? lol

View attachment 635846

A technical diver is trained on the understanding that problems must be solved under water because the surface is not available.

For a recreational diver, problems usually should be solved under water, but if not, the surface is always available.

In the case of this picture, what the diver is doing is taught during beginning open water training, during one of the final pool sessions. It is not remotely an advanced skill. Many instructors have students do that skill while kneeling on the floor of the pool, but others have them do it in mid water, as she is doing it. I had them do it in mid water myself when I taught OW classes.

 

[Degenerate]

Lets say a Nitrox 32% diver does a 30m dive rock bottom for 40 minutes, that can be done on a single tank safely.

For most people that could definitely not be done safely on a single tank.
Using a SAC of 15lpm (which is probably lower than what the average diver has) you would need ~2700l of gas for that dive.
You would barely get by with a 100cf tank on that dive, but there would be pretty much zero margin for error.
I'm talking about divers in general here, we all know you have the SAC of a fish because you've mentioned it in every single thread you've participated in for the past month, but making a statement that a dive plan like that is in any way safe for the large majority of divers is ignorant and reckless, mate...

 

[yle]

In my AOW where we did 3 deep dives there was always a drop bottle at I believe the safety stop depth but in these dives none; not even when we were at 33-36M. On one dive we were at 35-36M just minutes into it and one of the divers panicked, he started breathing real fast and was down to 1000 psi. At what depth should there be a drop bottle (I’m not even sure that’s the proper term) just for sh&*$ and giggles?

You've actually asked a few questions together without realizing it.

First, as so many others have replied already: always plan your dives, including gas requirements. This doesn't have to be complicated, but it is an important step to help mitigate problems.

Second, recognize that what you are taught in courses, like your AOW course, may or may not be standard practice everywhere in the diving community. Some things you are taught, e.g. leaving a tank hanging at 5 meters during a deep dive, are optional practices that are introduced during the class. The instructor should explain the advantages and disadvantages of these practices. It's also nice when they can tell you how common such practices are in the diving community (i.e. how likely you will be to see them.)

Third... the best way for you to figure out which things you learned in your courses are standard practice and which are not is to just dive as much as possible and learn from experience. In this case, you'll find that hanging a tank at 5 meters is not really a common practice (although I've seen it done a few times.) Expecting divers to manage their gas supply, however, definitely is a common practice.