Question Redundancies

[stretchthepenn]

Sort of the whole reason I started this thread... pretty much came to be the other day while testing/setting up my new gear. I was in a pool getting everywhere where I wanted it and trying out all the new kit. At least three times my scubapro G3 lost access to the transmitter. All the stuff is new and this was the first time any of it had been in the water. This was pretty much the spirit of the thread and my initial question.

The dive computer was working... the Air Integration... MOSTLY. Would I need to stop a dive because the transmitter decided to take a lunch? I wouldn't think so... I had my console with the SPG and depth gauge on it (depth and everything else on the computer was working).

Transmitters and computers sometimes lose comms. It happens. But the computer will tell you that it happened (at least Shearwaters do, with a big yellow "LOST COMMS"), and moving the computer closer to the transmitter for a few seconds fixes the problem. I'm assuming, based on your post, that the same thing happened to you.

Thus, losing comms is a momentary glitch that lacks a negative end result, I don't see a need for the redundant console.

 

[went_postal]

Transmitters and computers sometimes lose comms. It happens. But the computer will tell you that it happened (at least Shearwaters do, with a big yellow "LOST COMMS"), and moving the computer closer to the transmitter for a few seconds fixes the problem. I'm assuming, based on your post, that the same thing happened to you.

Thus, losing comms is a momentary glitch that lacks a negative end result, I don't see a need for the redundant console.

Loosing comms for a moment I get but loosing it multiple times is a hazard.

Also... one of the nice "features" of a computer is the computed bottom time. Near as I can tell with most of the computers out there if they lose comms the bottom timer becomes useless per their instruction manuals.

So... I get it. I've had a few dives since I started this thread and I do dive with a console that has depth and air on it even though my computer has depth and air on them as well. So far... the console had not caused any entanglement or other problems. So for ME... its working out.

We also found another way to resolve some of the comm issues... Added a ~5" length of hose to the transmitter. So now instead of being directly on the 1st stage it sticks out a little bit. This has provided two things: 1) better communication with the computer and 2) limits someone accidentally trying to hoist a bottle/bc from the first stage and grabbing the transmitter (I've heard more than one story about transmitters being broken by inattentive deck hands).

So for right now... I am diving with my apple watch ultra2 w/Oceanic on my left hand, my G3 on my right and a console.

 

[inquis]

Near as I can tell with most of the computers out there if they lose comms the bottom timer becomes useless per their instruction manuals.

I'm afraid you've interpreted the manuals incorrectly. AFAIK, ALL computers will continue to track & display bottom time when AI comms are lost. Perhaps you are thinking of the "remaining gas time"? Or do you have an example manual excerpt?

 

[NothingClever]

But now how do you know when you've reached a safety stop depth if you don't have anything reporting your depth?

Experience.

 

[Belzelbub]

I don't look at it as just loss of data.

If you are using your computer to monitor your depth and air pressure... if that unit stops doing that for whatever reason. Sure... end the dive. But now how do you know when you've reached a safety stop depth if you don't have anything reporting your depth?

I know this is older, but it does seem to point to a bit of a misunderstanding that I'll reference below.

If you are diving recreationally, and have a computer failure, this is not as dire as it may seem. Time to ascend, but you are likely diving with a buddy, so can do the safety stop as usual.

If the diving is serious enough (mostly outside the realm of this sub-forum), then a redundant dive computer is strongly recommended.

Loosing comms for a moment I get but loosing it multiple times is a hazard.

Also... one of the nice "features" of a computer is the computed bottom time. Near as I can tell with most of the computers out there if they lose comms the bottom timer becomes useless per their instruction manuals.

Losing comms momentarily, and a computer failure are two completely different things. If losing comms multiple times, then something is amiss. I've been diving with AI wireless transmitters for many years. Early on (Oceanic transmitter and Oceanic DC) I noticed a couple short sections with no comms. Never saw it during the dive, but saw it in the profile later. At that point, I was finding which arm, and which side I wanted the transmitter on. Since I've settled on that, I no longer have an issue. I've never seen lost comms during a dive since. I change batteries on a regular basis, so that's one thing I don't have to worry about.

If there is a communication issue between the DC and the transmitter, and that is the only problem, all other functions of the DC will continue to work just fine. It will still calculate your bottom time, NDL, ascent rate, and everything else. It just will not be able to show pressure or calculate your remaining GAS time.

We also found another way to resolve some of the comm issues... Added a ~5" length of hose to the transmitter. So now instead of being directly on the 1st stage it sticks out a little bit. This has provided two things: 1) better communication with the computer and 2) limits someone accidentally trying to hoist a bottle/bc from the first stage and grabbing the transmitter (I've heard more than one story about transmitters being broken by inattentive deck hands).

Some do that. If it works for you then no problems. I mount my transmitter directly to my 1st stage. Works fine. The deck hand grabbing the transmitter as a handle is likely not an issue any more. I could see this being a problem when transmitters first came out, but today, it'd be difficult to find a crew member that hasn't seen lots of transmitters.

Also, on the transmitter failure. Not all transmitters are created equal. Some manufacturers seem to have a hard time with this. Others just seem to work.

 

[lizardland]

Personally I'm quite a minimalist diver and I think there is a lot to be said for diving with the absolute bare minimum, lowest level of technology equipment you can find. Understand how to do that first then layer in technology when and if it helps. There can be a real illusion with all new technology that up until that point we were only just barely surviving without it. It clearly was not the case and, with maybe the exception of rebreathers, LED lights and maybe scooters, technology hasn't really brought more than a fairly small benefit to diving in my opinion. I also firmly believe that more is not better than enough, especially when it comes to data.

Losing displays is an inconvenience, not a danger. Even in technical diving it's debatable. You either have enough gas or you don't. You either made a contingency for not knowing your stop depths or you didn't. If you didn't then you weren't technical diving, you were engaged in ******* about. In recreational diving you should never be in such a hole where it really matters.

If you think you need to carry an analogue back-up because it is more reliable than whatever the primary is then ditch the primary and use the back up. In my experience the big problem in diving is that new technology is often half-baked and it starts getting in the way of diving rather than helping it. If a piece of kit failing has the potential to cause big issues on a dive and that piece of kit isn't as reliable as it can possibly be then it better be bringing some really major benefits that I cannot get in an easier or simpler way.

My own way of diving is that I add in a new piece of kit when there is no other option. Modern diving seems to be ratchet up the complexity as your starting point. I feel old and cynical (and didn't realise I was either ).

 

[landphil]

Solo diving I carry 2 of a lot of important things. But for regular rec diving the only backup I feel is important is my analog pressure gauge. Every other piece of info, like depth and NDL and dive time is "close enough" on my buddy's computer. But if my AI computer fails, having to estimate my remaining gas kind of limits how we can safely finish a dive.

 

[went_postal]

I'm afraid you've interpreted the manuals incorrectly. AFAIK, ALL computers will continue to track & display bottom time when AI comms are lost. Perhaps you are thinking of the "remaining gas time"? Or do you have an example manual excerpt?

It does continue to count bottom time... but the timer restarts. I will try and find the section that explains it.

 

[Belzelbub]

It does continue to count bottom time... but the timer restarts. I will try and find the section that explains it.

Just trying to follow this. Are you saying that your elapsed dive time resets if your computer loses communication with the transmitter?

This is truly odd behavior. I can't think of a reason why a DC manufacturer would do that. I've never seen that happen on my Oceanic where I have seen some loss of comms. Dive Time, NDL, and everything else seemed to continue as normal.

 

[went_postal]

Just trying to follow this. Are you saying that your elapsed dive time resets if your computer loses communication with the transmitter?

This is truly odd behavior. I can't think of a reason why a DC manufacturer would do that. I've never seen that happen on my Oceanic where I have seen some loss of comms. Dive Time, NDL, and everything else seemed to continue as normal.

Not dive time... RBT - Remaining Bottom Time. That counter is based on air consumption and when the access to the air is lost... that timer more or less resets.

So yes.. the overall dive timer continues but the RBT gets flaky.