Gauges-Why Bother?

[FishDiver]

This is not a troll, but I am playing the Devil's Advocate.

I have a decent, not exceptional SCR of 15 LPM or .5 CFM. With a standard 80 cf tank air is always the limiting factor when diving depths of less than 70 feet.

In my area dive shops commonly offer DM lead double shore dives. All divers wear computers but the DM's NEVER look at them or ask people for their individual deco load. Surface intervals are always one hour. Most dives are 18m (60ft) or less.

I have completed dives to 150ft and often use nitrox on dives between 25 and 35 meters so I am certainly not saying that gauges have no place. My question is for shallow dives (<70 ft) that are all many divers do, why bother with anything but an SPG?

 

[Peter Guy]

Well, my husband would tell you that you don't absolutely need the SPG, either! He learned to dive when they didn't HAVE depth gauges or SPGs, and you dove until you ran out of air, pulled your J valve and ascended. Of course, it got interesting when the J valve had already gotten bumped or otherwise moved, and you turned out not to have any reserve any more . . .

Probably the biggest utility of a depth gauge in the kind of dive you're describing is to help the diver control ascent rate and to place a safety stop. Of course, if one stays with the DM, he can control all of that, but that goes against the idea that a diver ought to be able to conduct any portion of the dive for himself if it turns out to be necessary.

 

[MikeFerrara]

I don't use a computer at all but there are plenty of sites where I dive that are shallow enough and/or I know the site well enough that I always know my profile without a depth guage. I wouldn't have any problem diving those sites without one because I still know what my profile is.

I guess my answer is that a depth guage or computer is one way to track your your profile but not the only way.

 

[Sam Miller III]

Well, my husband would tell you that you don't absolutely need the SPG, either! He learned to dive when they didn't HAVE depth gauges or SPGs, and you dove until you ran out of air, pulled your J valve and ascended."...
_____________________________________________________________________
Hummm --Interesting!

Depth gauges appear in every US Diver catalog from 1952 to date
Depth gauges appear and are recomended in the 1948 Spaco Aqua lung instruction manual as well as the LA County UW receration manual of 1954.

SPG appeared on the market in 1954, manufactured by Marmac. By 1960s they were very common -many dive companys were marketing them.
Example-US Divers Sea Sea=#7013, $19.95, Voit and Sportsways also marketed them

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

...Of course, it got interesting when the J valve had already gotten bumped or otherwise moved, and you turned out not to have any reserve any more . . .
___________________________________________________________
The wise and knowledgeable diver of that era would disassemble the value, reverse the cam activator and reassemble the valve. Therefore, the valve was actived by pushing UP rather than pulling down, eliminating the possibility of accidental activation by bumping or entanglement.

Lets all endeavor to preserve diving history but lets preserve it correctly --no embelishements please.

SDM

 

[spectrum]

My question is for shallow dives (<70 ft) that are all many divers do, why bother with anything but an SPG?

Assuming the reationship of depth, air consumption, SI and supply you cite it is correct that the whole dive day is inherently self regulated.

On most shore dives a depth gauge is more for reference and interest than it is for any dive management need. However I would not want to dive without it for a few reasons;
*If you do not know the site terribly well you could end up deeper than planned, especially in blue water
*Lacking a visual reference it's very handy in making a controlled ascent. Going slower than your bubbles is a traditional fallback here.
*Knowing how your depth is changing supports navigation.

Compass? Well there are plenty out there just going for the swim with divers who don't understand them so I guess you could say they are expendable. :11: Knowing the site and following natural cues works to a point. If you are follwing the leader then hope it's a good one.

Computer; Absolutely expendable for the dives you talk about. When you start going past 2 dives a day, diving on sucessive days, using nitrox (especially assorted mixes) , higher capacity cylinders or going past 60 feet on multilevel dives the value blooms.

Also the DM may be looking more than you realize.

Pete

 

[Halthron]

Well, my husband would tell you that

::cough cough::

 

[agilis]

It seems to me that the issue being raised is really about depth gauges. Everyone seems to agree that an SPG is necessary. A compass is not a gauge, and placing total reliance on an air-integrated computer is not the smartest thing to do.
I have a light, streamlined scuba set up that I use under docks and in other very shallow areas while collecting fish. These areas often have limited visibility and fairly strong currents, precluding snorkeling. I use a 40cf tank, and a small SPG, but no depth gauge, and no BC. In any other application, I think a depth gauge is essential, absolutely indispensable. Proper rates of ascent, saftey stops, and the need to know exactly how deep you have been (and for how long) require a depth gauge. General time/depth limitations and the ability to do approximate mental calculations in that connection should be a requirement for certification. Computers, I think, are very useful for fine tuning what you have already figured out, and as a saftey back up. I can't imagine entrusting my life to a battery.

 

[kidspot]

Well, my husband would tell you ...

Why do I think that Peter forgot to log off and Lynne forgot to log in

While there are sites I know well enough that I don't need a computer and could dive without my depth gauge, it means knowing the site well and what to anticipate/how to plan. I've seen divers "following" a guide and not pay attention to their gauges accumulate 14 minutes of deco because they did the whole dive 5-10 fsw deeper than their guide. It's not your guides responsibility to make sure you dive responsibly, it's his job to make sure you see as much as possible and gets you back to the boat/starting point... If you decide to dive gaugeless, it means a lot more planning and greater familiarity with that site imho - you can take as many risks as you like, so long as you are willing to take responsibility for them as well... and I wouldn't take those kinds of risks when diving with a group as you can put them in jeopardy as well.

 

[Thalassamania]

What I suggest you do is get a poorly adjusted non-ballanced regulator. Then when it starts to get hard to breathe you can ascend a little and get a few more breaths, this will get you to the surface (and was what many of us really did in the old days).<G>

 

[drbill]

When I started diving, we had no PSI or depth gauges initially. I still keep my analog PSI gauge for purposes of gas management since I know my approximate air consumption at the different depths I dive. I keep an analog depth gauge in the event my computer fails (as it has) and am looking to buy a backup bottom timer or computer.

I prefer using them even at "shallow" depths (70 ft and above).