Gauge backup or not?

[RAWalker]

Exactly!!!

If a diver were to have no faith in either air integrated computers or wireless air integrated computers, then don't bother spending money on them. What's the point of getting one and then add a gauge? Might as well go with a gauge and a non-air integrated computer and save the money.

If you have no faith in your equipment then you should have made a better selection of said equipment.

It's not a matter faith in the devices I have absolute faith in the fact that given enough time each and every type of instrument would fail.
This is a matter of using probability and statistic with instruments of increased accuracy to management risk to a level that an individual is comfortable with. I'd expect an engineer to understand how they interelate that and what part redundancy plays in reducing the risk. These risks are not just the risk of DCS but also the risk of loosing dive time on a trip due to a failure.

 

[Nemrod]

It's not a matter faith in the devices I have absolute faith in the fact that given enough time each and every type of instrument would fail.
This is a matter of using probability and statistic with instruments of increased accuracy to management risk to a level that an individual is comfortable with. I'd expect an engineer to understand how they interelate that and what part redundancy plays in reducing the risk. These risks are not just the risk of DCS but also the risk of loosing dive time on a trip due to a failure.

Here are the facts, where one mechanical spg was previously considered adequate for single tank no-deco scuba, users of air integrated units now find themselves with two pressure instruments because they are concerned about the reliability of the air integrated unit and then starting threads asking if they should have redundancy.

As to old school or whatever you are going on about, the air integrated spg function is not what is tracking the nitrogen loading, the dive computer function is tracking that information and my dive computer does not have air integration and even if it did, I would put that piece of silliness in a shoe box and loose it. Old school, lol.

Failure of a quality mechanical spg is exceeding rare compared to failure of hose integrated pressure units. A mechanical spg does not have to be accurate to the numbers on the gauge, it just needs to go up when you fill the tank and down when you breath it, when the spg is at ambient, notice the "zero" point, when the needle hits that point, you are OOA.

N

 

[RAWalker]

Failure of a quality mechanical spg is exceeding rare compared to failure of hose integrated pressure units. A mechanical spg does not have to be accurate to the numbers on the gauge, it just needs to go up when you fill the tank and down when you breath it, when the spg is at ambient, notice the "zero" point, when the needle hits that point, you are OOA.

N

Failure of a quality mechanical SPG is exceedingly more common than most people realize often it goes unnoticed until it creates a OOA incident or just stops functioning all together. In the case of a failure reading lower than actual pressure it may never be noticed and never causes a critical condition yet it is still a failure.

Even without AI feature on your computer if the computer dies you may not be able to safely convert to tables and continue diving due to the fact that the table may show you in violation where the computer tracking real time nitrogen loading and PO2 would not. This is the reason for redundancy of computers even if you don't use AI and why the SPG as a backup is inferior. Would you like to be on a expensive live aboard and be told you need to stop diving for 6 hours or the rest of the day? Those are facts!

As a side note just because a divers uses AI doesn't require the backup be AI just use a compatible algorithym that is equally or less conservative for backup. If the need arises to use the backup computer on a subsequent dive a SPG will need to be added but valid data from prior dives insure the safety margin of your nitrogen load and PO2 with the backup computer.

The reason many divers opt for AI features is that in addition to tracking realtime nitrogen load it also gives you realtime calculations of dive time remaining (based on tank pressure, depth, PO2 and nitrogen load) and reminder alarms for depth, turn around, safety stops, PO2 and Nitrogen load. Also based on the realtime data surface interval and subsequent dive planning are enhanced. In doing this it makes it easy for divers to maximize their dive time.

I have a quality SPG just in case it's needed. I prefer to leave it in the reg bag where it has been for the last 3 years. Who knows maybe one day I'll be diving one of those places where wireless just won't work. So far I haven't found one to get my SPG wet in.

 

[bubbleblowindude]

GUEFundiesDiver?

I dont know what that is, but I received my training from IAOID (International association of Internet Divers) where I was able to show equivelency to other agencies Advanced Helitrox without getting in the water. I know there are others here who might qualify if interested, as the time logged in and arguing about the semantics of scuba diving will qualify you as well.

 

[Blackwood]

What if you get a sprain in your neck and cannot look to the left D ring, maybe have two spgs on the right side also.

Naw, just unclip it and bring it to your face

 

[fnfalman]

It's not a matter faith in the devices I have absolute faith in the fact that given enough time each and every type of instrument would fail.
This is a matter of using probability and statistic with instruments of increased accuracy to management risk to a level that an individual is comfortable with. I'd expect an engineer to understand how they interelate that and what part redundancy plays in reducing the risk. These risks are not just the risk of DCS but also the risk of loosing dive time on a trip due to a failure.

So, would you use a backup gauge if you were using gauge/computer combination?

When is enough redundancy too much?

I'm all confused now. Are you advocating diving with an AI computer/wireless AI computer AND a gauge at the same time or are you advocating having a set of gauges in your dive bag as backup? Those are two different issues.

I have a set of SPG in my dive bag for if my 'puter conk out for whatever reason. I don't dive with both AI computer AND SPG at the same time, and neither are you.

 

[Nemrod]

So, would you use a backup gauge if you were using gauge/computer combination?

When is enough redundancy too much?

I'm all confused now. Are you advocating diving with an AI computer/wireless AI computer AND a gauge at the same time or are you advocating having a set of gauges in your dive bag as backup? Those are two different issues.

I have a set of SPG in my dive bag for if my 'puter conk out for whatever reason. I don't dive with both AI computer AND SPG at the same time, and neither are you.

I am confused also because I think what they are attempting to justify is two of each, spg, wireless spg, computer for a total of six instruments.

N

 

[RAWalker]

I advocate using a backup particularly if using a computer whether it is AI or not.
I also advocate understanding the difference in using a computer or tables and gauge.
Because of the difference I understand (as should other computer users) that a computer can be a better backup to a computer and a SPG and tables can lead to a senerio that could keep you out of the water where the backup computer would not.

The pressure gauge reliability/accuracy issue is a separate issue that proper knowledge and practices can keep you in relative safety in any case whether B&G SPG or Wireless digital.

The choices come down to what the diver wishes to accomplish in terms of dive conditions, personal comfort and personal risk assessment.

For me this mean 2 instruments under most but not all conditions.

When diving for simple recreation at local shore sites if a computer failed I'd simply abort the dive and call it a day. So far even this hasn't happened with my computers.

 

[SeaArch1]

My computer is a wrist mounted AI unit that i have had fail. I always keep a simple spg clipped on. I have found never to exclusively trust electronics when your in the water.

 

[Paladin]

I have no worries about computer failure. SPG backed up with a J valve and a watch. Works for me.