Shearwater Owners with AI, do you dive with a SPG?

[Belzelbub]

I am in the "both" camp when I dive single-tank, at least for now. The main reason is that the transmitter has a battery. I know that in due course, the battery will get low before it then needs to be replaced altogether. I don't want to make assumptions about how quickly the battery goes from first seeing the red-light to unreliable transmission to finally, dead.

This is a risk that is easily mitigated. The batteries are pretty cheap. I make it a point to change them every year. I've been doing this pretty much since I started diving with wrist mount AI about 10 years ago. Still using that same PPS transmitter.

There is also the (probably small) probability that the transmitter has an electronics failure or is damaged on the boat. I think it is a little more fragile than an SPG made of tempered glass and steel. In any of these situations, I can continue the dive with no interruptions. If it's dive #1 of a day with 4 or 5 dives planned, I can continue the remaining dives with no inconvenience, and without worrying about whether there is a wrench on the boat.

Again, most likely easily mitigated. Biggest risk would be if someone were to use it as a handle to lift gear. That's probably not too common anymore as transmitters are fairly common and boat crews should be aware of them. Some use a short hose to avoid that. Either direct mounted, or on a short hose, the transmitter is out of the way and fairly well protected between BC and tank.

I keep an SPG in my SAD kit. Along with spare o rings and a wrench to change out if necessary. Never need to worry if one is on the boat, as I brought them with me.

 

[gordonscuba]

This is a risk that is easily mitigated. The batteries are pretty cheap. I make it a point to change them every year. I've been doing this pretty much since I started diving with wrist mount AI about 10 years ago. Still using that same PPS transmitter.

Again, most likely easily mitigated. Biggest risk would be if someone were to use it as a handle to lift gear. That's probably not too common anymore as transmitters are fairly common and boat crews should be aware of them. Some use a short hose to avoid that. Either direct mounted, or on a short hose, the transmitter is out of the way and fairly well protected between BC and tank.

I keep an SPG in my SAD kit. Along with spare o rings and a wrench to change out if necessary. Never need to worry if one is on the boat, as I brought them with me.

Regarding the Shearwater swift batteries, I agree they are cheap and easy to change, but to do it preemptively is one more thing to remember... with my setup I can just change the battery when it actually does die, and otherwise, never think about it. I also sometimes do shore dives where there is a nontrivial land hike from the car to the entry point, and the closest SAD kit is in the car. I consider keeping an SPG clipped to my hip D-ring to be extremely simple and easy, so I'm willing to keep it if there is even a small chance that it may help a diving day go smoothly. People who think it is an additional point of failure should also strongly resist introducing an additional high pressure hose between the first stage and the transmitter, yet I see that a lot.

 

[Belzelbub]

Regarding the Shearwater swift batteries, I agree they are cheap and easy to change, but to do it preemptively is one more thing to remember... with my setup I can just change the battery when it actually does die, and otherwise, never think about it.

I just change mine when I take my regulators in for service. I remove the transmitter an install the plug before taking them in to the shop. Then I change the battery while the regs are being serviced. Reinstall and test when I get them back.

I also sometimes do shore dives where there is a nontrivial land hike from the car to the entry point, and the closest SAD kit is in the car. I consider keeping an SPG clipped to my hip D-ring to be extremely simple and easy, so I'm willing to keep it if there is even a small chance that it may help a diving day go smoothly.

That's a fair point. I don't do very many shore or inland dives, and they usually don't involve a fair walk like you described. I could definitely see that being a consideration. Though, I'm not sure as the transmitters (PPS anyway) are pretty reliable. I test before diving, and being electronics (battery aside), they tend to fail on startup in most instances. So, I would see I have No COMMS and be able to rectify. Though, I'm usually diving from a boat, so everything I need is available, and no hike back to the car.

People who think it is an additional point of failure should also strongly resist introducing an additional high pressure hose between the first stage and the transmitter, yet I see that a lot.

No argument there. It does add additional failure points. I mount my transmitter directly to the 1st stage.

 

[nz03]

yes

 

[Thunder Struck]

Something I also like about running both is that when working with a class or diving with new divers I find that the act of physically putting the SPG in front of my face helps to reinforce for them to check their air as well. While I already know my air is good and don't need to check, I want them to see it's a routine and regular part of the dive. Often times it's monkey-see-monkey-do and when I look at my SPG they will often do the same. Just glancing at my wrist doesn't convey anything to them.

 

[Dan]

YES! For redundancy.

I had my Teric's antenna failed to read my pressure transmitter in the middle of a week of liveaboard trip. So, I used SPG for the rest of the week of diving without AI. Sent my bad Teric to Dive-Tronix after the trip. They verified that I indeed had a broken antenna.

 

[ScubaWithTurk]

Something I also like about running both is that when working with a class or diving with new divers I find that the act of physically putting the SPG in front of my face helps to reinforce for them to check their air as well. While I already know my air is good and don't need to check, I want them to see it's a routine and regular part of the dive. Often times it's monkey-see-monkey-do and when I look at my SPG they will often do the same. Just glancing at my wrist doesn't convey anything to them.

I don't believe this is needed with proper teaching. Now I am not saying you teach improperly but I use AI every time I teach and have had no issues.

We talk a lot about gas management as well as it being their dive and their life. They learn to check the dive time and depth and then make a guess as to how much gas they have prior to ever looking at it. This helps them to understand time, depth and gas consumption. They don't need to see me check my gas because they are already aware that they need to be in control of their dive and their gas.

 

[BlueTrin]

I used to have both for about 200 dives, I used the AI only for statistics when uploading. Never had a failure.

A tech asked me to remove the AI after in my OC setup during a cave class, I never put it back because I had switched to CC now and I don’t need the statistics as much at the moment.

 

[gmerick]

I don't think I'll be doing do this, but I'm curious how you position them on the tank? Band the transmitter straight down and simultaneously bend the SPG up towards the valve? Band it all downwards until you encounter a transmitter failure and then re-jigger the SPG to a viewable position? Something else? Any pictures?

It is visible on my profile avatar - Reg to splitter hose routed down along tank. Transmitter under top elastic band. SPG hanging free down the tank. Gauge is easy to see by grabbing gauge and looking down (through my gauge reader mask).

 

[Rilelen]

I use both on my single tank, and just an SPG on doubles (I leave my transmitter on my yoke reg and don't move it over). I'll second the note that others have made about how important social learning is for new divers; modeling behavior (checking the SPG) increases desired behaviors, and I check my SPG frequently when diving with new folks (even though I can of course see it just fine on my Teric).