Diving with gradient factors for a new recreational diver

[Wibble]

How was this table created ? I am interested in generating some of the buhlman NDLs for the GF factors in between.

Use MultiDeco and play with the settings

 

[scubadada]

How was this table created ? I am interested in generating some of the buhlman NDLs for the GF factors in between.

Use MultiDeco and play with the settings

I used the NDL planner on my Teric and on an Oceanic Geo 2.

I also use MultiDeco but it does not give you NDLs

 

[inquis]

I used the NDL planner on my Teric

A note for others doing this who may not live at sea level, this will skew the times since the "current" atmospheric pressure is used.

Subsurface is another tool that will give NDL times directly (arguably easier than MultiDeco).

 

[scubadada]

A note for others doing this who may not live at sea level, this will skew the times since the "current" atmospheric pressure is used...

@inquisit makes a good point. That is the reason I included the atmospheric pressure for the table I posted earlier, 1013 millibar Diving with gradient factors for a new recreational diver

This table shows the range of NDLs with an atmospheric pressure of between 985-1028 millibar. Normal pressure at sea level is 1013.25 millibar. You can compare the sea level NDLs for air at a GF high of 95 from the other table to these ranges.

 

[badelaar]

I used the NDL planner on my Teric and on an Oceanic Geo 2.

I also use MultiDeco but it does not give you NDLs

Thanks, I tried MulticDeco but it didn 't show NDLs indeed. Subsurface does but it is a bit cumbersome, as is only shows when hoovering over the graph.

 

[inquis]

Subsurface does but it is a bit cumbersome, as is only shows when hoovering over the graph.

Look at the table on the right. NDL is shown on the line listing the dive depth. (That's when the plan has you starting your ascent.)

 

[exodusmaximus]

I think without technical dive training, it's not really smart or feasible to do "deco stops" on a rec dive. The main problem I see is that you could potentially consider that the stops can be ignored, since you aren't "actually" in deco. However, in this case then, how do you know if you truly ARE in deco (as in, a direct ascent to the surface is likely to cause injury) or not? Basically, the readout on your computer will no longer reflect reality, and you might then not believe it, making the whole situation too complicated.

My suggestion? This is what I do:
1) dive with a shearwater so you have access to your "surfaceGF", or what your % nitrogen loading is if you were magically transported to the surface.
2) set the gradient factors to low conservation (GF95), so that you aren't going to be running into deco far before your other diving mates.
3) keep an eye on the SurfGF. When you get to your safety stop, track it until it goes below 75 (equivalent to the high conservatism setting).

Now you effectively have the best of both worlds. Your computer isn't lying to you, saying "you're risking serious injury by surfacing now!" on a relatively benign dive, but you can also track your nitrogen loading so that you can offgas to a high degree before surfacing. I know a couple of people on here who effectively dive this way.

I got a recommended "deep stop" at about 15m few times when diving close to 40m on air (without passing NDL). Standard conservative setting on my recreational i770r

 

[boulderjohn]

I got a recommended "deep stop" at about 15m few times when diving close to 40m on air (without passing NDL). Standard conservative setting on my recreational i770r

Recommended by whom?

 

[Subcooled]

Let me be annoying for a moment. Forgive me, I've studied physics.

This sentence: since you aren't "actually" in deco
should read: since you aren't subject to mandatory decompression stops (or mandatory offgassing at constant pressure)
- compression and decompression happens on every dive.

I applaud the quotation marks, though!

Yeah, I know. I'm annoying

 

[lowwall]

Recommended by whom?

By the i770r dive computer? According to the manual, whenever the Deep Stop setting is on, it triggers on any dive that exceeds 80' and is set to half the max depth. The manual doesn't say (or I couldn't find) whether it is on by default which would qualify as a recommendation.

The manual also has this curious section under Specifications. I guess it's there if users want to chase down further info.

"DIVE COMPUTER PERFORMANCE
• Bühlmann ZHL-16C based Z+ algorithm
• Decompression in agreement with Bühlmann ZHL-16C
• No Decompression Deep Stops - Morroni, Bennett
• Decompression Deep Stops (not recommended) - Blatteau, Gerth, Gutvik
• Altitude - Bühlmann, IANTD, RDP (Cross)
• Altitude corrections and O2 limits based on NOAA tables"