Use a backup SPG with air integration?

[hammet]

Thinking about the perdix AI. I get it that two is one and one is none when it comes to equipment failures, but what is the consensus for warm rec diving only?

 

[tbone1004]

I think you should have a SPG/Hose on the boat in your save a dive kit, but I don't personally see the need to bring one with you on every dive. Many disagree

 

[tursiops]

It is a recreational dive. You always can come to the surface. If your AI goes out, you end the dive and come to the surface. Just like if your computer stops, you end the dive and come to the surface. The issue is not what you do if the AI goes out, the issue is what do you do on the NEXT dive? With an SPG and hose (and wrench) in your kit, you can keep diving.

 

[JohnN]

Thinking about the perdix AI. I get it that two is one and one is none when it comes to equipment failures, but what is the consensus for warm rec diving only?

How often do you get out diving? For me it's a bitch to get out and I'd be completely pissed if the AI decided to blurp. The backup gauge doesn't add any drag and my dive can continue

 

[tbone1004]

How often do you get out diving? For me it's a bitch to get out and I'd be completely pissed if the AI decided to blurp. The backup gauge doesn't add any drag and my dive can continue

do proper, conservative gas planning, and set a dive time limit predicated on your max depth vs. planned avg and a surface value of 700psi and so long as your SAC rate stays consistent, you can run to that time limit with minimal risk. You could also plan based on a SAC of 1.0 which is more conservative than your actual and while when you call the dive on time, you are likely to surface somewhere around 1000-1500psi, you at least got to dive to that point

 

[Dan]

I have 2 dives computers (one with AI) & SPG. Had experience 2 type of problems during couple diving trips that avoided from thumbing the dives:

Case 1:
My non AI dive computer (SUUNTO D4) was accidentally set on free diving mode. I didn't notice it until I was 80 ft deep. So, I relied on the other AI dive computer (SUUNTO Cobra3) for the rest of the dive. When I was back on the boat, D4 locked out for 48 hours as it thought I was free diving for 45 minutes.

Case 2:
The Cobra3 ran out of battery during one of a week-long liveaboard trip. So, I continued my remaining dives with the backup SPG & D4.

I use 2" Hinghland Thinline SPG with 1/4" x 30" Miflex hose, so the setup is small & light.

 

[divezonescuba]

My wife has tried to go down to an air2 and AI transmitter. That's leaves only one hose for your primary. She always travels with a hosed AI computer and has had to revert back to it multiple times.

You wouldn't even notice a small gauge on a short hose wire tied to the inflator hose.

I use a Perdix AI, a backup wrist computer, and an analog pressure gauge. Double redundancy.

 

[tbone1004]

to @Dan_T 's reference. The technology Suunto uses is not exactly known for reliability compared to the type of technology used by the PPS transmitters that Shearwater uses though you don't reference and loss of connection

Case 1: the Shearwater is not able to lock you out regardless of what you do, so no real benefit to fix that situation
Case 2: the Shearwater uses AA batteries of basically any voltage. Alkaline, SAFT, NiMH, Li-Po, it doesn't care. Can be changed with a coin or the end of a triglide on your harness and the o-ring is a standard DIN o-ring. SPG or backup computer wouldn't have really done anything to that one provided you carried a spare AA battery of some variety

 

[wetb4igetinthewater]

If you look at the manual, you see that Shearwater recommends an SPG as backup. I follow this advice, even for recreational dives, as I don't want to have to end a dive prematurely in the unlikely event that the connection goes kaput for whatever reason.

 

[Dan]

to @Dan_T 's reference. The technology Suunto uses is not exactly known for reliability compared to the type of technology used by the PPS transmitters that Shearwater uses though you don't reference and loss of connection

Case 1: the Shearwater is not able to lock you out regardless of what you do, so no real benefit to fix that situation
Case 2: the Shearwater uses AA batteries of basically any voltage. Alkaline, SAFT, NiMH, Li-Po, it doesn't care. Can be changed with a coin or the end of a triglide on your harness and the o-ring is a standard DIN o-ring. SPG or backup computer wouldn't have really done anything to that one provided you carried a spare AA battery of some variety

Sounds like I should have Shearwater

However these SUUNTOs have kept me saved for the last 8 years I've diving with. So, I try to make the best use of them until they go caput.

After the Case 2, I start bringing spare CR2450 batteries, O-ring kit for them & right screwdriver for DIY battery replacement.