GF99/99
Contributor
Transmitter on O2 & transmitter on Dil. No SPG's
If your out of gas your out of gas, how is an SPG going to to help.
Shearwater Owners with AI, do you dive with a SPG?
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Transmitter on O2 & transmitter on Dil. No SPG's
If your out of gas your out of gas, how is an SPG going to to help.
Gas pressures on a rebreather are very much secondary information as you're using so little oxygen and diluent -- a fraction of a tiny cylinder's capacity even for a long dive.
On the other hand, open circuit gas pressures are critical information as everything depends upon it: turn points, planning, even backup plans.
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I appreciate your sharing the image!
My head is in sidemount mode right now, and the way your gear is configured in the picture with single 1st and 2nd stages on each could pass for SM setups , and why I wasn't sure how you placed the transmitter & SPG portion. But it's easy to envision what you done working with single or double backmount.
Thanks!
gordonscuba
Contributor
I think the photo was someone else's. On sidemount, I forgo the mechanical SPGs and just screw one transmitter directly into each first stage. I found it slightly easier and faster to check both pressures simultaneously with a single glance to the Teric on my wrist, versus with two mechanical SPGs it's always going to be two separate checks.
- Messages
- 232
- Reaction score
- 291
- # of dives
- 200 - 499
Yes, my mistake. The picture was from a post by @gmerick on page 1
Did you copy me? Dang!
I have never lost connection underwater. Adding an SPG does nothing but add another failure point.
The question I always ask people when they discuss this is "Do you dive with two SPGs?" If not, why dive with an SPG and a transmitter?
I also use the transmitter on the O2 and dil for the chestmount CCR.
The question I always ask people when they discuss this is "Do you dive with two SPGs?" If not, why dive with an SPG and a transmitter?
I also use the transmitter on the O2 and dil for the chestmount CCR.
Belzelbub
Contributor
Exactly. I don’t really understand why there are so many in the “both” camp. In addition to the extra failure point, you also have two gauges that may not agree. Which one is right? The failure mode on an SPG sucks. I’ve seen one fail underwater. The needle just stuck at the pressure at the point of failure. I’ve never seen a transmitter fail underwater, but have seen a failed transmitter topside. It just read “No COMMS” on my computer. One of those failure modes is detectable at first glance. The other is not.
gordonscuba
Contributor
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. 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.
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