Computers: air integrated or not?

[DA Aquamaster]

michaelp68 once bubbled...
What are your preferences for dive computers, air integrated or not, and why?

Thanks in advance for your thoughts.

I own an air integrated computer and refer to it occasionally more to see if it agrees with me and my estimates than to use it as a tool to plan the dive. (not the best idea in my opinion)

I know my air consumption, I know what I will need to surface and I know what I want in reserve at the end of the dive (1/3 in deep or overhead situations, 500 psi back at the boat in others) So in practice I will turn the dive when my planned bottom time is reached or when the pre calculated psi reading to turn the dive is reached - which ever comes first. And given my generally low air consumption the dive buddie's air remaining is almost always the deciding factor and the air integration feature on my computer is largely unused.

 

[String]

I never thought of running an analog SPG off one port and an air integrated dive computer off the other!!!

That is actually not a bad idea. Good backup. Kind of bulky though! Maybe a little tangly too.

The DIR guys are going to laugh at you. But then they laugh at everybody else as well !! [/B]

Get one of the small "button" SPGs that people use on ponys - you could clip that off somewhere and it wouldnt be bulky at all - it would give you a redundant SPG. Theres the argument about adding an extra failiure point but those are so rare i think having it is a good idea.

Pity i cant afford an AI vytec to put it into practice

 

[nwdiver2]

Buy the vytec then later buy the transmitter, this is one of the few hosless computers you can buy in stages. The Computer itself is all you will ever need.

 

[ew1usnr]

I'm reading this thread about having an battery powered air integrated SPG, and then using a mechanical SPG as backup in case the battery quits. ????????

You started with one gauge and now you have two. Instead of adding another gauge, what do you guys think of using a j-valve and pull rod as a backup to the electronic gauge? The j-valve would be less clutter and less of a potential failure point than adding another pressure gauge, and it would still serve as an indicator of remaining tank pressure.

 

[DA Aquamaster]

I started diving with a J valve in the early 80's and they have their downsides. Unless it is a depth compensating reserve valve (Scubapro used to make them in that flavor) the reserve air supply is inadequate for deep diving. To make it worse, most J's were designed to be used with 2250 psi steel tanks. The burst disc can easily be changed to accomodate the higher service pressure but the reserve pressure remains unchanged. And 300 psi in a in a steel tank is actually more air than 300 psi in an AL 80, so the already low resere gets down right scary if you are at depth with an AL 80.

Also it was pretty common for the reserve lever to get accidently pulled during the dive, so that when the tank got hard to breathe, you reached back and pulled the reserve only to discover you were in fact really out of air. The proper spelling is "S C R E W E D".

A J valve also has more opportunities to leak than a K valve and slow leaks around the reserve mechanisim are also pretty common. Parts are also not always available for older vlaves which aggravates the problem.

If you monitor your air supply as often as you should a failure of the air integrated computer or electronic SPG will not leave you high and dry as you will have apretty good idea what you have left and can end the dive accordingly.

The button style SPG is normally just that - a button that gets screwed into an HP port. They are basically impossible to see during the dive and even if they are on a stage bottle the guage offers a pretty rough reference to air capacity. There are mini spg's around and SP makes a nice brass one, but they are relatively spendy and you really need to consider if you really need one.

I would consider one if I used a hoseless air integreated computer as the transmission/reception can be problematic in some cases. They make a little extension to get the transmitter out away from the tank and reg and this is supposed to help, but in my opinion just poses an entanglement hazard.

In my experience with normal hose equipped air integrated computers, you still get an SPG reading if the computer dumps on you and most offer enough battery capacity to survive a dive with a low battery in cold water. With most air integrated computers as long as you preflight the unit to ensure the battery is not low, you'll be fine.

 

[ew1usnr]

That was a good reply. Thanks.

 

[ENikS]

I personally like AI computers. In my personal opinion they are a lot more reliable then mechanical SPG (well I’m EE and deal with computers on a daily bases so I tend to trust them). My basic points on reliability are: No moving parts, more precise readings, if it goes belly up it will just go blank and will not mislead you with incorrect readings (the needle will not get stuck).
I also have hyper aqualand watch which I have on my wrist. It is a lot smaller then dive computer and gives me time and depth. It also serves as backup timer and depth gauge. In case my computer dies I still know time and depth of my dive and I can still dive tables. I carry spare mechanical SPG (kind of DIR style ) in my save a dive kit so if Cobra gives up my vacations will not be wasted.
I know it is not the most cost effective solution but I generated all this equipment over the years and all together it gives me full proof solution for almost any situation.
If I do deco, I just put computer into gauge mode and enjoy precise instrument with logging capability.

Eugene

 

[Antonio Boga]

Years ago, when Uwatec Air X appeared on the market, I ran to my LDS to buy it. But when I studied the computer, I saw that the RBT said 0 minutes when yoour tank still had 50At (that means 1/4 of the capacity). Tuo could change this limit via PC to 30At, but you could neve overpass this limit. That means that you will see 0 RBT whern tou still had air for a lot of minutes in shallow depths.

I know this is safer, but it's not fair. I like the instruments tell me the truth. Why not tell me that I'm 50 meters down when I'm really only 40?. Of course it's safer, but I don't think anyone wants an unreal information.

Frow these old days until now, I've been lloking at the market, to see if it appears any AI Computer with 0 RBT at 0AT. But nothing (as far as I know).

I would use the RBT as a matter of information, not for pushing my limits, but then it's worthless if it lies me.

In case I would use an AI Computer, I would also use an SPG as a backup, so it doesn't frees me of a hose, so I thin I will keep using not AI Computers.

If anyoneone knows any AI Computer with 0RBT at 0AT, pleas let me know.