Question When do we speak of technical diving ?

[Capt Jim Wyatt]

Let us say a divers SAC rate has been previously calculated at .75 FT3/min.

That Diver goes to 66 feet(3 ata), dives a square profile stays 30 mins
That diver uses (.75 X 30 X 3) = 67.5 cubic feet used.

Same diver, same time same square type profile at 99 feet(4 ata) (.75 X 30 X 4) = 90 cubic feet used.

 

[johndiver999]

let’s say the no deco limit for air is 60 minutes at 60 feet and 15 at 130 feet. Those are guesses, I think 130 has a shorter ndl.
Say sac is 1 cuft /min. 60 feet is about 3 atm so burn 3 cfm for 60 is 180 cuft

130 is about 5 atm so burn is 5 cfm for 15 minutes is 75 cuft.

 

[LordHavoc]

I recommend to never do that course. It is done in poor equipment, with poor training. I suggest serious technical training with TDI or GUE etc.

 

[Capt Jim Wyatt]

I have some formulas here that may help refresh memories.

Gas Math for diving

 

[L13]

I just ran NDL dives in SubSurface to 20m(65ft) and 30m(100ft) with GF high 80%, SAC(RMV)=20l/min.

• 20m for 30min : gas consumption 1837 liters of air.
• 30m for 13min : gas consumption 1067 liters of air.

It appears that physics agrees with @johndiver999

 

[lowwall]

Let us say a divers SAC rate has been previously calculated at .75 FT3/min.

That Diver goes to 66 feet(3 ata), dives a square profile stays 30 mins
That diver uses (.75 X 30 X 3) = 67.5 cubic feet used.

Same diver, same time same square type profile at 99 feet(4 ata) (.75 X 30 X 4) = 90 cubic feet used.

Yes, but @johndiver999's point was about diving to no deco limits at various depths. The bottom time is not equal.

I just looked at an old PADI table in meters. NDL at 20m is 45 minutes. At 30m it is 20 minutes.
.75x45x3=101.25 cu. ft
.75x20x4=60 cu ft (didn't even need the calculator)

 

[Capt Jim Wyatt]

Yes, but @johndiver999's point was about diving to no deco limits at various depths.

OK. I wasn't picking up on that distinction.

 

[Blackcrusader]

I'm ok with the fact that "my" definition makes it possible that the same dive profile is technical for one diver and not technical for another.

For me I do not consider deco as being technical as I was trained in deco and did not see that as not being anything other than normal diving at the time. Also it was on 21% not of the new fangled gases out then. Now over the years yes I have done Nitrox course. Is diving nitrox now a technical dive.?
Now let's say I dive nitrox 32% on a 30m dive and have a dive of 45 mins. I would need 19 mins deco time on 32% nitrox. Lets make it 20. I also sling an al 80 with Nitrox 40%. I ascend to deco stop but do not change my DC to 40%. I just do the stop with 32% factored in but use 40% for the duration of the stop.
Nitrox course allows anyone to use 40% for recreational diving. Does not require special equipment. My GF is 45/95

As I am deco trained I just plan for my gas consumption with my buddy. I would need around 2000 liters of gas for the dive. Maybe use an AL100 for my main tank so have more than enough gas even if was just on the single tank. Of course this would be at one of the dive locations I know well with little or no currents. Now a deco stop of 20 mins means just hovering and watching the tiny critters on the reef.
Even on an NDL dive sometimes I will do 20 mins just looking at things in shallow water.
Just my humble opinion.

If some want to say that having to do a deco stop make's it a technical dive then guess I've been a technical diving since 1986.

I suppose I just got used to calling it sports diving.

 

[Lorenzoid]

Is diving nitrox now a technical dive.?

From what I have read of the history of "technical" diving, nitrox was considered out of the bounds of recreational diving when sport divers first started experimenting with it. The major training agencies wanted nothing to do with it. Anything the training agencies declared to be outside their domain was something else, which would soon be dubbed technical diving. In a post above I mused that maybe the definition of technical diving is a moving target--a slowly expanding envelope.

 

[Blackcrusader]

From what I have read of the history of "technical" diving, nitrox was considered out of the bounds of recreational diving when sport divers first started experimenting with it. The major training agencies wanted nothing to do with it. Anything the training agencies declared to be outside their domain was something else, which would soon be dubbed technical diving. In a post above I mused that maybe the definition of technical diving is a moving target--a slowly expanding envelope.

Yes my BSAC instructor was a commercial diving instructor as well and he at the time was also of the opinion that anything other than 21% was going to need special skills. Nitrox allowed divers to stay deeper for longer and run themselves short on gas lol.

I'm going to stick with my deco diving not being technical diving but sports diving. Says so right in my BSAC training manuals lol.