Error in current issue (July/Aug. 2008) of "Alert Diver" Magazine?

[sytech]

In the article "Adapting to Change" (starts on p. 22) the author is trying to make the point that the rapidly advancing technology coupled with a seeming lack of standardization between mfrs. regarding say, gauges and how to read them can be problematic and dangerous.

In the middle of p. 23 he says:

"A diver familiar with one computer could easily make a mistake interpreting the display on an unfamiliar dive computer or in programming an unfamiliar yet somewhat similar device. Imagine what could happen to a diver breathing standard air but using a computer programmed for enriched air nitrox 36-a breathing mixture of air with a higher-than-normal oxygen content formulated for 'deeper, longer dives'. Such a mistake could be serious, especially if the diver doesn't recognize the mistake until the dive is over and he begins to feel a twinge, tingle or pain".

My question is Nitrox-36 for "deeper, longer dives"??????

Comments will be appreciated.



Sy

[drbill]

More bottom time depending on the depth, but I hope they don't do much deeper dives on 36.

I think the author has a good point. However, it can apply not only to equipment made by different manufacturers, but also different models made by the same manufacturer. Computer displays and functions obviously vary from model to model, and I've experienced some difficulty and the need for "retraining" to read my newer computer from the same manufacturer as my old standby. Of course I'm an "old dog," so it is hard for me to learn new tricks!

[BKP]

I think you can interpret that as "deep, longer, dives," [within the MOD].

However, I agree with drbill... I'd like to see a Nitrox "flag" on the main screen, as a standard, just indicating whether the computer is profiling air or EAN.

[deco_martini]

When they talk about deeper/longer dives, they most likely mean spending more time at 100 or 80 feet on a recreational dive. (versus a 60 for 50 profile)

[debersole]

I know the screen on my Sunto mosquito says EAN vs. air and all of my other computers (Uwatec, Zeagle N2ition, and VR3) all display the breathing gas on the screen.

The only problem with a nitrox "flag" is, obviously, not all nitrox is created equal. While a lot of divers dive standard mixes such as EAN32 or EAN36, basic nitrox divers can dive anything from EAN21 (air) to EAN40 with greatly different MODs. Then there are the two gas computers for advanced nitrox, etc.

And don't get me started on us crazy trimix divers! :)

I guess I would say is that it is your responsibility to know your breathing gas and to know your computer. If you don't know your computer, dive tables.

To answer the original question, I'm sure the author was well intentioned and was referring to "nitrox" allowing for longer no-decompression limits compared to air at the same depth due to the lower partial pressure of nitrogen. However, as you implied, nitrox is certainly not for "deeper" dives as as the fraction of oxygen in the breathing gas increases your MOD decreases.

Just my 2 cents.

[ianw2]

Nicely put, Doug. Your last paragraph answweres the OP on the money. Unfortunately, this misstatement/msiconception seems to be rife among the divng community.

BTW - My Suunto Cobra and Vytec 2 also display the NITROX flag. I usually dive EAN21.

[don Francisco]

I think you'd have to ask Bill Clinton what "deeper" means.

The article is on point about the non-standardization of equipment. I've buddied with divers who having a porblem swim up to me showing me a air-integrated computer console. I have NO IDEA from looking at it, as to what the problem might be. I've had to become familiar with 2 different computers which for instance differ in how they show hitting the NDL. Mine says "ascend/ceiling", my wife's says "DECO". (?!)

I'd hate to be a divemaster today, having to deal with all kinds of "instrumention" issues, besides the differences in hand signs country to country, and all the other newly introduced variables.

The article also touched on but, I feel, glossed over another important issue in diver training. That is the reduced emphasis in theory in OW courses. New divers are being trained straight to computer, with little or no training on using tables, or dive profiles & planning. This leaves them totally dependant on hardware with insufficient programming of the onboard (between the ears) computer for effective problem solving. dF

[dumpsterDiver]

I thought the article on reels and equipment associated with sMB deployment presented some things incorrectly. The first problem is a big picture of a big yellow plastic line holder that a person manually wraps up. The implication is that this would be used to deploy a smb. That type of gear would be entirely inappropriate for deployment at depth since it is pretty much unmanagable once the smb takes off for the surface. (of course it is fine for towing a float around in shallow water).


Another big problem I had was that the author indicated that the SMB should always be deployed slowly when using a reel. The diver is supposedly directed to control the reel so line is taken off slowly. ANYONE who has ever deployed a decent sized SMB from any depth knows that the thing takes off like a bat out of hell once it has ascended 50 or more feet and to try to really control the rate of line taken off the reel is impossible to do when nuetrally bouyant in the water column (unless you want to go for a ride, that is). We commonly use a 6-8 foot smb with maybe 75 lbs of bouyancy and this thing really takes off. Some people say you shouldn't use a reel for this application (I've heard)but, the diver needs to be prepared to drop the reel if a problem develops NOT try to deploy it slowly??????