What defines a "Deco" dive?

[ligersandtions]

Back to basics, I guess what defines Deco vs NDL is if the diver has a free ascent path (30'-60'/min) to the surface from depth. A MinDeco dive is not a NDL dive.

I would agree that a min deco dive is a "deco dive"....I also happen to believe that all dives are "deco dives". However, I also believe that a min deco dive is a recreational (i.e. not a technical) dive. I use the terms NDL and MDL interchangeably....and use the term "NDL" more often because I don't want to try to teach others about min deco.

 

[DwayneJ]

Tyler, borrowing your post -- sorry, nothing against it . . .

Nicole and Stephen were not technical diving, People!

These silly statements are just mud in the water.

Using GUE MDL techniques and no direct ascent to the surface makes it a deco/technical dive. Obviously needed doubles for the profile and gas redundancy although you are correct, doubles by themselves do not make a technical dive.

These are not silly statements - If specific facts are "modified" to better suit a point of view, then what other aspects of the story are accurate? You are directly responding to another post made stating it was an NDL dive, yet in the very first post there is a statement "...stop at 40..." and we subsequently clarified it was a deco dive using GUE Minimum Deco Limits with no free ascent to the surface.

Amazing how the same tail has two different summaries depending on what forum you use...
Near Miss on Marissa Dive Charters (5/15/11) - San Diego

Dwayne

 

[Mr Carcharodon]

Min deco uses a depth average compared to a "setpoint". MDL dives are less than the setpoint. MDL is not the same as NDL in that stops are done on 10 fsw (3 msw) intervals from half max depth up the the surface for MDL, but NDL allows a direct ascent. For most rec dives with a safety stop the run times look about the the same.

 

[Blackwood]

Using GUE MDL techniques and no direct ascent to the surface makes it a deco/technical dive. Obviously needed doubles for the profile and gas redundancy although you are correct, doubles by themselves do not make a technical dive.

These are not silly statements - If specific facts are "modified" to better suit a point of view, then what other aspects of the story are accurate? You are directly responding to another post made stating it was an NDL dive, yet in the very first post there is a statement "...stop at 40..." and we subsequently clarified it was a deco dive using GUE Minimum Deco Limits with no free ascent to the surface.

Amazing how the same tail has two different summaries depending on what forum you use...
Near Miss on Marissa Dive Charters (5/15/11) - San Diego

Dwayne

If I demand a safety stop, am I now on a deco/technical dive? Maybe so.

At some point, it's all personal choice. What model I elect to use and whether I elect to modify it (e.g. gradient factors) are personal choices. Same story for whether I elect to add deep or shallow stops to what the model computes, or in the case of NDL tables whether I hold to a slower rate than that which the model uses (e.g. PADI's table uses 60fpm, but they recommend 30fpm).

In this case they ran a bottom profile from which they could have surfaced directly without hosing most computers.

 

[TSandM]

PADI requires a "mandatory safety stop" for certain dive profiles . . . are they then technical dives?

All models assume an ascent rate . . . GUE's simply assumes 30 fpm to half maximal depth, and 10 fpm thereafter. The 10 fpm rate is usually accomplished by ascending 10 feet, and then staying there until a full minute has gone by from the time you left the last depth. These are short "stops", but basically just result in the desired ascent rate. I don't find this at all technical diving.

 

[ligersandtions]

Using GUE MDL techniques and no direct ascent to the surface makes it a deco/technical dive. Obviously needed doubles for the profile and gas redundancy although you are correct, doubles by themselves do not make a technical dive.

Doubles were NOT needed for the dive profile. Based on our SAC rates, we needed right around 100cf for the dive. With a single HP130 (the single tank we most commonly use), that would have been more than sufficient. Also, had we ever reached min gas, we would have begun our ascent....it was not a "requirement" that we max our our NDL/MDL, but just what we had planned (i.e. if we hadn't been able to max it out on the amount of gas we had, we'd have done what we could).

Additionally, if you even bothered to read the dive matrix thread that you linked, you'd see that we said that we did not use doubles for redundancy. We treated the two cylinders on our back as one big cylinder. We could easily have dived the profile on a single tank, but had planned to bring doubles such that we wouldn't need fills between dives (since at the time, they only filled air). We could have brought two single cylinders....but one set of doubles was much easier.

These are not silly statements - If specific facts are "modified" to better suit a point of view, then what other aspects of the story are accurate? You are directly responding to another post made stating it was an NDL dive, yet in the very first post there is a statement "...stop at 40..." and we subsequently clarified it was a deco dive using GUE Minimum Deco Limits with no free ascent to the surface.

Amazing how the same tail has two different summaries depending on what forum you use...
Near Miss on Marissa Dive Charters (5/15/11) - San Diego

Dwayne

Funny that you seem to think what was stated (by me) in the two threads are somehow different from one another. I've maintained the same stance in both threads....and that's that we did a recreational dive (whether you want to call it NDL/MDL doesn't make a difference to me), the crew didn't notice that they were drifting away and we were left sitting on a mooring ball for 27 minutes, and that they didn't address the safety concerns.

FWIW, I've been informed that they are now employing the use of a drift alarm and actively monitoring boat location while divers are in the water. That's all I had wanted from the time the incident happened till now, so I'm glad that something changed their mind. But you, who seem to disagree with EVERYTHING I've said, keep bumping the thread....I don't get it

 

[FWADIVER]

Funny that you seem to think what was stated (by me) in the two threads are somehow different from one another. I

now you are twisting words, he said the conclusions in each thread was different. Get off your soapbox already and go diving.

 

[Jax]

Using GUE MDL techniques and no direct ascent to the surface makes it a deco/technical dive.

Dwayne

Seriously? :w-t-f: I know the MDL techniques. Will you explain what your "no direct ascent to the surface" means?

I am not following this at all.

 

[ScubaSteve]

Looks like Dwayne and Voodoo are still trying to slime Nicole and Steven. The boat changed their equipment to prevent the incident that happened so it seems something good came from this. Maybe you two can lose the hatred and go diving.

 

[ScubaFeenD]

It is the case that the minimum decompression pauses, as GUE has them, are meant to slow the ascent rate and control bubble formation. It is theory, that when placed into practice works very well. HOWEVER, there is no time, on an MDL dive, that a diver cannot go directly to the surface at 30fpm as with any other dive agencies no decompression dives.