Does everyone really need an SPG? (w/transmitter)

[diver00011]

As a general principle redundancy is a good thing to have on solo dives. If primary piece of equipment fails, you fall back to redundant and end the dive.

In practice, my SPG (actually a second computer on a hose) is more of a "save a dive" sort of thing for the 1 in 50 dives where I didn't realize my transmitter was failing to pair before entering the water.

But recently that redundant computer had to go back to the manufacturer for a warranty replacement, and I got really used to diving without that extra hose. I now have the replacement sitting on my workbench and I keep forgetting to reinstall it.

 

[Kimela]

My husband and I both had Cobras that failed - and he had a Datamask that wouldn't maintain connection - so when we were diving with an AI computer we also had an SPG and a backup computer (Gekko). My Cobra died a second time and wasn't salvageable. Then my Gekko died. Redundancy is sometimes very useful.

 

[woodcarver]

GF and I have identical Suunto D4i setups. There have been 2 instances that I managed to pair both computers to her transmitter. The SPG w/ depth gauge enabled me to continue the dives. On another trip, her battery died in her computer. Again, the SPG w/ depth gauge allowed her to finish the dive and then we got her battery changed. The battery in my transmitter quit once also. No need to end the dive
That "extra" hose has never caused me any problems, but has kept us diving a few times. A little redundancy is a good thing, imo.

 

[tridacna]

I keep a mini-SPG on my first stage. Lets me check tank pressure pre-dive without turning on my computer/s.

 

[napDiver]

In terms of reliability, I suspect a transmitter is roughly the same as an SPG in this day in age. This assumes it has adequate battery levels. In subsurface you can check your battery levels if there are any questions. So a prudent diver shouldnt have a dead AI transmitter due to battery issues.

Now if you dive with both. That's fine, but its like diving with 2x AI or 2x SPGs. What you gain is redundancy vs cost, clutter, and an extra failure point. But to be honest, I dont think it matters for open water one way or another.

Open water recreation, I dive with AI only. I have a spg in my bag cause my instructor and gf thought it to be prudent. I've used it a few times out of 200 dives but that's because I forgot my computer or my computer was out of batts. And for open water recreational w/ a trusted dive buddy, I have no issues diving with no spg and/or computer if I absolutely had to.

In a SM configuration, one day I plan to use 2x AI with a corresponding computer for each. So if one DC or AI fails, I'd still know my total gas via switching tanks at a time interval.

I think an spg only has only two real advantages. 1) You can see the instaneous reaction of the needle moving. 2) cost is much cheaper

 

[Anthony A.]

Years ago my suunto crapped out while in Aruba. Missed a week of diving cause of it. Ive since had an spg on my rigs and dont care for hoseless anymore. Its 100% reliable for me now. If i went back to transmitter, i would still keep the spg for backup but its annoying for a travel rig so i just use spg. Saves me money from having to buy an AI dc.

 

[TMHeimer]

With two computers no. If you have one computer the SPG can be the backup. If your computer fails you can continue the dive IF you have an analog depth gauge AND you marked the time you descended on your dive watch AND you know how to use tables and have them with you (or memorized as per the depth you know you're gunna do). That's what I do--show of hands who also does this.....
Also, my compass is in my console so I'd have to buy a wrist compass without the console. Or I could buy a second DC and a wrist compass and have 3 things on my wrists--instead of two and a console clipped.
Also, for the vast majority of my dives being 30' or shallower, I am almost never bothering with the DC (less to wash, less to get busted), yet I like to know my depth, time, etc.

 

[Marie13]

I’m noticing a pattern here - the transmitter issues here seem to be non-Shearwater.

 

[GreggS]

In subsurface you can check your battery levels if there are any questions. So a prudent diver shouldnt have a dead AI transmitter due to battery issues.

Okay, I may be dense or something, but I've been using Subsurface for a while now and I've never seen where you can check the transmitter battery level. And after reading your post, I've check every menu item in Subsurface and still can't find it. Please inform me as to where that information can be found.

 

[dirkhh]

It depends on which dive computer you have. Not all make this information available. If it is, you'll find it under "Extra Info" with every dive.
For example on every Shearwater dive computer. Or on newer Suuntos (EON Steel, Core, etc).