Sidemount - SPG and Transmitter - HP Splitter? Button SPG?

[lostsheep]

I assume everything I’m diving with is going to fail at the worst possible time.

The spg assembly (Guage itself, spool Orings, hp hose) has got to have the shortest mtbf of anything on my rig.

 

[Umuntu]

I assume everything I’m diving with is going to fail at the worst possible time.

The spg assembly (Guage itself, spool Orings, hp hose) has got to have the shortest mtbf of anything on my rig.

The high pressure system in your rig is designed to transmit pressure and not high flow rates of air, unlike your low pressure system. When the o-rings fail you will get a very low flow of bubbles. Scuba hp hoses are (were ?) designed to leak bubbles along the length of the hose when they begin to fail. SPGs spring tension changes with age and should be recalibrated, but only industrial pressure gauges tend to be calibrated. The variance tends to be minor for scuba applications and it’s easier to replace very old gauges.

Make informed choices for the type of diving that you do. In OW applications it hardly matters as you can always call a dive and head to your safety stop, assuming you/your buddy can assess your depth. If you are deep in a cave system you don’t want to be guessing how much air you have left if you're solely relying on AI and it fails.

I’m old enough to have had multiple laptops, PCs, tablets, household appliances etc. fail. AI and dive computers are not any more reliable than those electronics, if anything they are subjected to a harsher environment — water immersion under high pressure.

Yawn

 

[lostsheep]

Make informed choices for the type of diving that you do. In OW applications it hardly matters as you can always call a dive and head to your safety stop, assuming you/your buddy can assess your depth. If you are deep in a cave system you don’t want to be guessing how much air you have left if you're solely relying on AI and it fails.


Yawn

ASSume much sir?

The straw that broke this camels back with respect to spg vs ai was having a hp hose blow ~1800’ back in a cave. I would have much rather had a transmitter just stop telling me than to have actually lost gas. Knowing how much gas you have is irrelevant to your survival; clearly you don’t understand gas planning.

Lastly, why were you diving with laptops , PCs, tablets , and household appliances?

Please don’t answer the last question, it too was rhetorical.

 

[Umuntu]

Lastly, why were you diving with laptops , PCs, tablets , and household appliances?

Perhaps you are being deliberately dense in failing to understand an analogy … all electronic appliances are prone to failure, particularly as they are all composed of multiple components each of which is prone to failure. Dive computers are subject to harsher environments than most other types of electronic devices.

BTW, if your electronic appliance (eg dive computer) was manufactured during or shortly after the COVID epidemic, those appliances are experiencing higher rates of failure.

YAWN

 

[scottgrizzard]

After much ado, I pulled the spg's off my regulators, and just dive two transmitters. I have two computers now that can read them, so I don't lose everything if a computer fails.

What happens if a transmitter fails?... I give it a few minutes to see if it will reconnect, and then I thumb it. I still have one working transmitter, and I am pretty good about switching my tanks and feeling if they are even. I haven't had one of the new shearwater transmitters fail on me (sure...disconnect for a minute or two, but never a full fail), so I am okay with it.

That said, I did toss the spg's in my bag, so if it fails to connect pre-dive, I can swap it out.

 

[Watthem]

After much ado, I pulled the spg's off my regulators, and just dive two transmitters. I have two computers now that can read them, so I don't lose everything if a computer fails.

What happens if a transmitter fails?... I give it a few minutes to see if it will reconnect, and then I thumb it. I still have one working transmitter, and I am pretty good about switching my tanks and feeling if they are even. I haven't had one of the new shearwater transmitters fail on me (sure...disconnect for a minute or two, but never a full fail), so I am okay with it.

That said, I did toss the spg's in my bag, so if it fails to connect pre-dive, I can swap it out.

Wholeheartedly agree with everything said here--I almost exclusively side SM and long ago switches to TX only (directly screwed into 1st stages) with no analog backups, just a second AI computer

 

[Rickk]

Did some searching and found SPG vs. AI transmitter discussions for a variety of configurations, but not much specifically on setting up sidemount regs for both SPG and AI transmitters. I'm new to sidemount and working through the gear setup process with the eventual plan to use this configuration in caves. Using a Hollis K2 rig with steel HP100/LP85 tanks, if that's helpful.

My initial preference is to have both SPG and transmitter on each tank, but I'd be comfortable with just one or the other if that makes more sense. Leaning toward using an AI transmitter on a short HP hose with QD fittings (in the typical SPG position) plus a button SPG on the opposite side.

I'm aware of the potential additional failure points with the button SPG and QD fittings, and I'm generally good with both of those items from using them with other configurations. Any specific drawbacks to this setup for sidemount?

Also, is anyone using an HP splitter for SPG and AI transmitter on sidemount regs? If so, would love to see some pics of your setup and get your thoughts on how you like it.

Thanks,

Lance

I have transmitters in the traditional SPG position on a short HP hosecwith button SPG as a back up. I also use button SPGs on my deco tanks.

 

[rjack321]

After much ado, I pulled the spg's off my regulators, and just dive two transmitters. I have two computers now that can read them, so I don't lose everything if a computer fails.

What happens if a transmitter fails?... I give it a few minutes to see if it will reconnect, and then I thumb it. I still have one working transmitter, and I am pretty good about switching my tanks and feeling if they are even. I haven't had one of the new shearwater transmitters fail on me (sure...disconnect for a minute or two, but never a full fail), so I am okay with it.

That said, I did toss the spg's in my bag, so if it fails to connect pre-dive, I can swap it out.

You're more likely to have the battery run out than outright fail.