SPG and Computer?

[Sam G]

Hi,

I am relatively new to diving, and have been exclusively renting gear (besides mask/fins etc). I would like to start buying items as my budget allows, and haven't seen my specific question addressed (but please point me to a thread if it has).

Let's say I wanted to have regs as my first major purchase. I would have to buy a first/second stage primary, and then equip it with an octo. I would also need instruments as well, like an SPG/depth/compass console. When I've looked at prices however, the instruments seemed quite expensive considering there is no computer (e.g. the Oceanic Navcon at $229 MSRP). I have been happy so far diving just on tables/timers, but at that price point, wouldn't it just be better to buy a console computer? On the other hand, I tend to think I would prefer a wrist-mount computer when I do get that far along, but don't I still need the basic SPG etc on the HP line? Are there people out there with more efficient set-ups that I haven't noticed?

Thanks for your advice,
Sam

 

[muddiver]

Unless you purchase an Air Intagrated (AI) computer that has a connection to the first stage (either hard connetion with a hose or an electronic sending unit) to read the cylinder pressure, then yes you do need an SPG.

Where you cary your computer and compass is up to you. Just because you have an SPG on a hose does not mean the computer (and compass) must be on the hose. I have an AI computer that I strap to my wrist which gives me cylinder pressure and depth as well as dive time. Therefore the SPG, dive timer and depth guage functions are covered. I have not figured out what to do with the compass yet, but I think I will go with the Aries clip boot with a double snap bolt on my harness.

 

[ae3753]

Sam,

Welcome to diving and the fun of gear purchase.

After going through multiple set-ups, we've settled on using wrist mounted gauges (computer/bottom timer and compass) for easier accessibility/visibility. This makes ascents (and general diving) much easier.

For pressure, we use a simple brass and glass SPG on a HP hose (22" or 24"). This keeps our system very streamlined and unencumbered.

Consoles with SPG + Compass + Depth are bulkier and not as convenient as wrist mounted units.

Here's two pictures for comparison:
Console:

Wrist gauges and brass SPG:

As purchasing a computer or SPG, take a look at ScubaBoard's classifieds. Simple Air only computers or Bottom timers regularly go on sale for approx. $100-$150. In addition, SPGs with HP hoses are pretty inexpensive as well, usually < $80.

Good luck on the research.

 

[GrumpyOldGuy]

I have had a variety of dive setups. The console works, but I really dislike them. To much to dangle, to easy to get crunch on the boat and it requires more effort to pick it up and read it when diving. The wrist mount solutions avoid all these issues. I use an SPG and basic dive computer on my wrist because it is cost effective and KISS. I might be tempted to an AI if I had unlimited funds, but there are so many scuba toys to buy.

IMHO, there is one console some might consider if they have bad eyes, the ProPlus 2 has huge numbers which might make it worthwhile for some despite the other issues.

 

[Sam G]

Thanks for the replies. To those of you who use wrist computers and a simple SPG, do you have a depth gauge as well, or do you rely on the computer? If your computer crapped out, wouldn't you need a gauge to make a safe ascent?

thanks,
Sam

 

[GrumpyOldGuy]

The computer functions as the depth gauge, timer and computes your NDL.

If you ever need to ascend without a depth gauge, your buddy should be able to use his to set your rate. Failing that, ascend slower than your smallest bubbles. Then once you are close to the surface, you can count off your safety stop.

FYI: Basic dive computers are very reliable, they rarely fail during a dive. Common problems are dead battery, dead on start up or flooding after an improper battery change. For AI wireless, there is some additional complexity with the transmitter for the air pressure that can fail during a dive (loosing the link, etc.)


BTW: I have had one analog depth gauge die on me, never a computer. Just my experience, nothing significant.

 

[muddiver]

I just happen to have an old computer so I strap it to me as a backup to my primary computer. I bought it back when simple dive computers were around $100. Or just get a capillary tube guage

and strap it to your wrist as a back up. You will also need a watch.

I have had one computer failure and it was after a dive that I noticed that teh computer was reading way off from the reading of my backup computer. Since I had both it was no big deal and the manufacturer replaced it at no cost.

 

[Sinbad the Diver]

Last year I moved my computer (non-AI) to my wrist and have a console that has a depth gauge and compas on one side and an SPG on the other. In low viz when trying to navigate I find that setup to be optimal for me since I can see the compas and depth together...it also gives me a depth gauge as a backup to make a safe ascent in case my computer goes kaput.

 

[rongoodman]

Go for the SPG, avoid the bulky console. As you become more comfortable with you gas usage, you'll probably be referencing it less and less anyway, as your bottom timer/computer/watch becomes your primary instrument for keeping track of how much you've used and the SPG becomes the back-up.

 

[paddler3d]

Thanks for the replies. To those of you who use wrist computers and a simple SPG, do you have a depth gauge as well, or do you rely on the computer? If your computer crapped out, wouldn't you need a gauge to make a safe ascent?

thanks,
Sam

I have my SPG clipped to a D-ring on my left hip. I wear my computer on my left wrist. I wear my compass on my right wrist.

I have no other depth gauge.

Knock on wood, I have not had my computer go South on me while diving.

If your computer craps out, that is the end of the dive. I would make a nice slow ascent to the surface. To do this I would go with the rate that my buddy is ascending with and go off their depth gauge. If you didn't have a buddy (you should though at this stage in your diving game, you'd likely have a backup computer with you for situations just like this. Also there is the old PADI trick on not ascending faster than your slowest bubble. Although I believe this is faster than what most would suggest today.

I've heard of computer crapping out, but they seem to happen before the dive or after in the SI. I haven't heard of one that crapped out in the middle of the dive that wasn't the divers fault, i.e. - diving when it is flashing low bat at you.

Your regulator is going to be expensive. Don't skimp on this item. As they say, buy it right, buy it once.

If you think you may get into your local diving, look at what the locals use. What may work fine in warm waters may not the best for your local area.