Setting up a Reg for Travel

[vladimir]

Can you explain why? Mine has never had a problem that I know of...
Do people attach a second analog pressure gauge?

Yes, a lot of AI users attach an analog pressure gauge as backup. I don't bother for weekend trips, but I do for longer trips. I think there is a general consensus on Scubaboard that the analog gauges are more reliable, and my own experience bears that out. I have not, however, seen any broad statistical data that confirms that suspicion. What is certain is that your analog pressure gauge's battery won't quit on you.

 

[herman]

Can you explain why? Mine has never had a problem that I know of...
Do people attach a second analog pressure gauge?

I also realize it makes sense to keep things the way they are, I appreciate everyone's feedback.

First off, I do not like the transient response of AI gauges, in other words their sample rates is too slow. An early sign of reg problems or a tank valve almost closed is a swinging pressure gauge. So far, all of the AI's (hosed and otherwise) I have tested sample as a rate that mask the issue, not a good thing.
Then there is the possibility of failure. I have had 2 computers fail and another die during a dive due to batteries. While it's not an earth shattering event if you have been monitoring your gas, still it's a lot more of a deal if the computer is your only source of pressure info. I really like my computer and usually do not dive without it. However, the most critical bit of info I need under water is my tank pressure, I insist on a reliable indication of it. On the other hand SPGs rarely go bad unless grossly abused. The other problem with an AI dieing is you are no longer able to dive until you get some type of replacement.....usually a SPG. Might as well at least throw it in the checked baggage just in case.
Bottom line is you save little by leaving a simple SPG and hose at home but lose a lot if you AI dies. Cheap insurance IMO.

 

[Dave616]

vladimir and herman, thank you both for the detailed responses.

Do you guys have a favorite SPG? I currently own a Zeagle Slimline Pressure Gauge.

 

[RJP]

vladimir and herman, thank you both for the detailed responses.

Do you guys have a favorite SPG? I currently own a Zeagle Slimline Pressure Gauge.

While vladimir and herman are right - in theory and their own experience - in practice you can go an entire lifetime of diving with an AI computer (hosed or hoseless) and never have a problem. Millions of people dive AI computers without issue. (Sampling rate being too low and an issue sneaking up on you in the interim. Really? There are better ways to guard against your valve only being partially open.)

That said, I do bring an SPG and a depth/bottom timer with me on any dive trip in the unlikely event of an equipment failure. I keep it in my save-a-dive kit. (And I check to make sure my valve is all the way open.)

Your Zeagle Slimline Pressure Gauge is perfectly fine. Personally, I'd remove it from the rubber boot, as they can hide problems. (Though millions of people use SPGs with rubber boots with no problem.)

 

[herman]

While vladimir and herman are right - in theory and their own experience - in practice you can go an entire lifetime of diving with an AI computer (hosed or hoseless) and never have a problem. Millions of people dive AI computers without issue. (Sampling rate being too low and an issue sneaking up on you in the interim. Really? There are better ways to guard against your valve only being partially open.)

That said, I do bring an SPG and a depth/bottom timer with me on any dive trip in the unlikely event of an equipment failure. I keep it in my save-a-dive kit. (And I check to make sure my valve is all the way open.)
Your Zeagle Slimline Pressure Gauge is perfectly fine. Personally, I'd remove it from the rubber boot, as they can hide problems. (Though millions of people use SPGs with rubber boots with no problem.)

If you have total control of your tank valve it not an issue but there is little you can do about the "helpful" DM checking your tank valve while you are standing at the stern of a boat. An all too common occurrence in travel locations. A quick check for a swinging pressure gauge before descending will verify he has not been extra helpful, AIs lack the response time to show the problem. Finding it at depth is not the best option. I suppose you could make it a habit to check your tank valve after submerging but the SPG is easier and it can flag reg issues as well. A small piece of tape that was across the valve face that you missed during the inspection or when you allowed that helpful DM to set up your regs, for example. I have actully seen that happen and we caught it at the surface doing the SPG check. I am sure you don’t allow that and neither do I but let’s face it, a lot of divers do and those are the same ones that a partly open valve at depth would cause big issues for.
For anyone curious about the responce time of their AI computer, hook up a SPG along with it, crack open the tank valve and watch both while breathing off the reg. The SPG will swing, how much depends on how hard you inhale and how much you have the valve open, the AI on the other hand will not show any change most of the time unless you get lucky and hit it at the right time. Odds are you will not notice any differnce in the way your reg breaths but that will change at depth. Not a good place to realize you have a problem.

 

[vladimir]

In practice you can go an entire lifetime of diving with an AI computer (hosed or hoseless) and never have a problem. Millions of people dive AI computers without issue.

I agree with this. I try not to worry about low-probability, low-consequence events like computer failure. Bring an analog gauge--or don't.

 

[diver 85]

I pack my 1st, 2nd stage & octo in my carryon bag--wife does the same & we're ready to go...We use wrist computers that travel in the carryon's also....

 

[Dave616]

Your Zeagle Slimline Pressure Gauge is perfectly fine. Personally, I'd remove it from the rubber boot, as they can hide problems. (Though millions of people use SPGs with rubber boots with no problem.)

So if I run my AI with an SPG, would it be a good idea to attach the hoses together, and if so, what's the best way to connect them?

 

[RJP]

So if I run my AI with an SPG, would it be a good idea to attach the hoses together...

No

...and if so, what's the best way to connect them?

See above.



But seriously, the HP ports on your reg come out on opposite sides so trying to run the two hoses together is going to be problematic.

As mentioned above, there's no real good reason to have them both hooked up at the same time on a recreational dive. If either one fails (which is now twice as likely if you're running both) you're going to end that dive anyway. If it were me, I'd dive with the wrist computer and the AI computer and keep the SPG in my save-a-dive kit. Then, if the AI computer craps out on you you still have the wrist computer to safely end the dive with (depth, time, etc) and then you swap the AI for the SPG on your surface interval and just keep going without missing a dive on the trip.

 

[Dave616]

No



See above.



But seriously, the HP ports on your reg come out on opposite sides so trying to run the two hoses together is going to be problematic.

As mentioned above, there's no real good reason to have them both hooked up at the same time on a recreational dive. If either one fails (which is now twice as likely if you're running both) you're going to end that dive anyway. If it were me, I'd dive with the wrist computer and the AI computer and keep the SPG in my save-a-dive kit. Then, if the AI computer craps out on you you still have the wrist computer to safely end the dive with (depth, time, etc) and then you swap the AI for the SPG on your surface interval and just keep going without missing a dive on the trip.

That makes sense, I forgot about the port location problem.
I will do that, thank you for all the advice.

D