How important is a depth gauge as part of a reg set?

[drk5036]

If you were renting gear, what kind of half assed dive ops were you using that did not provide you with an operational depth gauge, and why would you accept that as normal? I own two dive computers (not cheap ones), and I would bet good money that both of those will fail long before my mechanical depth gauge quits.

Because I’ve always had a dive computer and not once have felt the need to look at my depth gauge. It was also never explained how to use it in my open water class, for example...we only ever used computers to measure depth. My guess would be the shops also don’t consider it essential equipment since they require everyone to have computers?

it was also in the Philippines, for what it’s worth. Second time was in Okinawa, and the gear didn’t have a depth gauge just SPG. Third time was in Malaysia (advanced open water), depth gauge needle didn’t move. After that I just bought my own gear

(FWIW I only use a single dive computer now, but always with a buddy and divemaster)

 

[Zef]

I dont think a backup analog depth gauge is very useful. For ascent rate one would need an additional timing device...most divers that I see who use a single computer when diving are not sporting a separate timing device to use in conjunction with their depth gauge...so in the event of a computer failure they are just estimating their ascent time, which is not something one really needs an analogue depth gauge to do.

Further, to continue diving with an analogue depth guage after a computer failure is not realy the safest thing to do, again one would need a separate timing device and know when the dive started and at what time point during the dive the computer failed....then one would also need to be familiar enough with a dive table and know the max depth....yet if multiple depths were explored during the dive then that would throw a wrench in those gears frome a safety perspective.

If diving with a computer, the prudent thing to do would be either:
1. End the dive in the event of failure, making as slow an ascent as prudently possible.

Or

2. Dive with a backup computer to switch to if the primary computer fails.

If one is going to dove with an analogue depth gauge, then plan the dive around a dive table and stick to the guage and bottom time limitations.

The idea of having an analogue guage so the dive is "not ruined" in the event of failure during a recreational dive is a rather specious argument that introduces risk into the equation for the purpose of pleasure (ulitmately the purpose of recreational diving), and that risk is better to be avoided. The risk is further compounded in scenarios where multiple dives are done in either the same day or over a series of succesive days.

-Z

 

[halocline]

Who says that I don't have the training?

I never said or even meant to imply that you don't have the training and experience needed to do the dives you describe. But the OP of this thread, the one seeking advice, is a new diver with 0-24 dives. He is talking about the need for redundancy in the dives that he is doing. I don't think your example of dives exceeding NDL is relevant to his question. Nobody is going to argue against the need for redundant information in technical (or 'semi-technical') diving.

 

[Ben_3]

For open water level diving I only have my depth on my computer. If it fails I will end the dive as safely as possible. My buddy should have some idea of what depth we are at unless his stuff failed too, hopefully unlikely.

 

[Bigbella]

I never said or even meant to imply that you don't have the training and experience needed to do the dives you describe. But the OP of this thread, the one seeking advice, is a new diver with 0-24 dives. He is talking about the need for redundancy in the dives that he is doing. I don't think your example of dives exceeding NDL is relevant to his question. Nobody is going to argue against the need for redundant information in technical (or 'semi-technical') diving.

Exceeding the NDL had nothing whatsoever to do with my recommendation for redundant equipment to a new diver -- nor was I suggesting that he do so.

Crap can fail at ten or thirty meters; either way, it is a drag and an end to a dive -- perhaps, even an expensive one, in the stickier parts of the world. I had a failure of electronics in the Coral Sea, years ago, but didn't miss a beat; and simply dove with tables and analogue instruments -- since a computer replacement was only about 120 nautical miles away . . .

 

[CT-Rich]

Don’t waste you money on a back up depth gauge. A puck computer will fit in the same space on your console. A new out of the box depth gauge will cost almost as much a slightly used puck computer and the DC will have far more utility.

A computer is not life support equipment and you will not drown if it fails. If you are pushing or exceeding the NDL, it has extremely important Information and a back up is appropriate. For the purposes planned and executed no NDL dive, I want four pieces of information: Tank pressure, depth, direction and time. For most of my diving (above 50’) tank pressure and direction are mission critical. The other stuff is nice to know, but not essential for getting out of the water safely. Even a failed AIDC Will not drown you, but it does mean you are turning the dive.

 

[Landau]

I always dive with a redundant depth gauge - my buddy's computer.

If either or our computers should fail we will abort the dive and use the one still working computer to measure our ascent and safety stop. Never needed to do that yet in 350+ dives.

Note: I only do recreational, no deco stop diving.

 

[CycleCat]

For the cost of a nice brass SPG I was able to buy a used computer console on ScubaBoard classifieds. So not only will I have redundant depth tracking, but redundant everything else too. And I can compare different algorithms betweencomputers.

 

[Altamira]

I always dive with a redundant depth gauge - my buddy's computer.

If either or our computers should fail we will abort the dive and use the one still working computer to measure our ascent and safety stop. Never needed to do that yet in 350+ dives.

Note: I only do recreational, no deco stop diving.

You a very fortunate to have a dive buddy that you can count on to be there when needed. Most of my dive buddies have been instabuddies, and I would not rely on any of them to be there for me when I need them the most. Although I am not a "certified" solo diver, I approach every dive as if I am on my own, and plan accordingly, and that includes having redundant gauges.

 

[Eric Sedletzky]

We’ve had this discussion many times in the past.
The only thing I can add that is if you decide you want to use a completely analog system with tables to back up your computer then you will need to run the tables along side your computer from the start, so that in the event your computer fails you will be able to calculate repetitive dives using pressure groups. You can’t just decide to start using tables on your next dive after a computer failure without having some clue about accumulated nitrogen load, and if your computer fails without you jotting something down on paper before hand you won’t have that.
And good luck trying to get the two systems to jive. The computer is very good at milking every drop of bottom time out of your NDL, where a table is not.