Quick Disconnect Dive Computers

[Scared Silly]

Another mention of padded sleeves. Time to look for them.

A beer cozy works reasonably well in many case.

On my last LOB (the Aquacat in Oct 2017), my dive computer, an Oceanic PP3 AI hosed DC, failed 108' on the first dive of the day.

I am curious to know what exactly failed. Was it the actual hose? If so what many people do not realize is that many (most?) QD systems are independent of the hose. That is the hose is just a std. HP hose where the female portion of the QD has been added on. It is rare that the QD is integral to the hose (Though I think the Oceanic may be). The same with the male portion of the QD it is not integral to the computer (Which I think is true of Oceanic). Though I there are some exceptions like the AA Cobalt. At the end of the day if the hose blows all one needs to is replace it. Or in the case where the QD is integral to the hose the male fitting can be removed from the computer and attached directly to a HP hose.

https://www.oceanicworldwide.com/us/media/wysiwyg/manuals/12-2169-r01_1.pdf

Also a dive computer can be submerged in water without the hose attached. So in a pinch one could still use it.

The bottomline is that folks should understand the in ends and outs of their gear a bit more. As everything I wrote above also applies to integrated inflators/backup regs. The QD while specialized to the inflator can be removed from the hose (a std. second stage hose).

 

[Hoag]

I am curious to know what exactly failed.

It was the computer itself. At first, the display was fine (when I hit the water), but by the time I got to depth (the bottom of the swim through was at 108ft), all that was displaying was my depth and everything else was just the LCD "8's ".

By the time I got to my safety stop, there was no display. Something inside the computer failed. It was on a QD, so if I had a 2nd PP3, I could have simply swapped it out for the one that failed.

 

[JackD342]

When you get your Vision, let me offer a word of advice on that HP QD hose. Unless there has been a recent change, that has one slightly unusual feature. Aside from the "bayonet" female fitting and the rubber hose protector, there is an additional QD "lock" that you twist closed to keep the QD from disconnecting by mistake.
Do NOT screw this part down tight!! Gently snug is all you need. If you actually tighten it, it may/will eventually jam closed and prevent you from removing the DC from the hose. It is a PITA to deal with after that.

 

[Scared Silly]

It was the computer itself.

Thanks ... that sucks. We actually had something similar. Gear did not arrive us so we used the boat's computers for the first day and a half. Then got our gear and computers. Did worry about N2 loading so the next couple of dives were conservative.

 

[stuartv]

@divinh If an SPG fails, the most likely failures will be from the spool, O-rings, or the hose itself. If the gauge is working when you splash, it is very unlikely the gauge itself will fail while you're in the water.

Having 2 SPGs on your rig is just doubling the chances of that happening. And for what benefit? Redundant computers are good because if one fails, the other allows you to continue your dive. Redundant SPGs are of no practical benefit (at least, in my opinion) because the vast majority of the time, if one fails, it will result in some level of gas loss and you'll have to end the dive early anyway. I.e. if a spool or O-ring or hose lets go, your dive is over, regardless of whether you have a redundant gauge. So, the extra SPG is, like I said, doubling your chances for a problem and giving almost zero benefit.

To me (just my personal opinion), the most reliable setup is one (known reliable*) AI transmitter and no other SPG. A spare SPG (or AI transmitter) would be in your kit, on the boat. A single AI transmitter is the least likely setup (other than no SPG at all) to have a failure that results in gas loss. At least, that's my perception. Any failure that does not involve gas loss is, to ME, just not that big a deal. As long as I have a backup I can switch to for the next dive, of course.

* My experience is with PPS transmitters, as used by Shearwater and others. I believe them to be very reliable. I have no opinion on other brands. My original transmitter is now 4 years old and has 200-ish dives on it and is still on the original battery. I would recommend to anyone to replace the transmitter battery per OEM specs, which is, I think at least once per year. I am still running mine with the original battery just because I have wanted to see how long it would actually last. And I haven't been using it for dives where having the battery die during the dive would be a real problem for me.

 

[divinh]

A beer cozy works reasonably well in many case.



I am curious to know what exactly failed. Was it the actual hose? If so what many people do not realize is that many (most?) QD systems are independent of the hose. That is the hose is just a std. HP hose where the female portion of the QD has been added on. It is rare that the QD is integral to the hose (Though I think the Oceanic may be). The same with the male portion of the QD it is not integral to the computer (Which I think is true of Oceanic). Though I there are some exceptions like the AA Cobalt. At the end of the day if the hose blows all one needs to is replace it. Or in the case where the QD is integral to the hose the male fitting can be removed from the computer and attached directly to a HP hose.

https://www.oceanicworldwide.com/us/media/wysiwyg/manuals/12-2169-r01_1.pdf

Also a dive computer can be submerged in water without the hose attached. So in a pinch one could still use it.

The bottomline is that folks should understand the in ends and outs of their gear a bit more. As everything I wrote above also applies to integrated inflators/backup regs. The QD while specialized to the inflator can be removed from the hose (a std. second stage hose).

That's great info to know. When I ordered my Deep6 reg, the SPG hose length was too short and I ended up getting a longer MiFlex from the local dive shop. Should the Vision's QD hose be too long or short, I can swap it out.

 

[divinh]

When you get your Vision, let me offer a word of advice on that HP QD hose. Unless there has been a recent change, that has one slightly unusual feature. Aside from the "bayonet" female fitting and the rubber hose protector, there is an additional QD "lock" that you twist closed to keep the QD from disconnecting by mistake.
Do NOT screw this part down tight!! Gently snug is all you need. If you actually tighten it, it may/will eventually jam closed and prevent you from removing the DC from the hose. It is a PITA to deal with after that.
View attachment 494334

Oh! Thanks for the advice! Noted!

 

[divinh]

@divinh If an SPG fails, the most likely failures will be from the spool, O-rings, or the hose itself. If the gauge is working when you splash, it is very unlikely the gauge itself will fail while you're in the water.

Having 2 SPGs on your rig is just doubling the chances of that happening. And for what benefit? Redundant computers are good because if one fails, the other allows you to continue your dive. Redundant SPGs are of no practical benefit (at least, in my opinion) because the vast majority of the time, if one fails, it will result in some level of gas loss and you'll have to end the dive early anyway. I.e. if a spool or O-ring or hose lets go, your dive is over, regardless of whether you have a redundant gauge. So, the extra SPG is, like I said, doubling your chances for a problem and giving almost zero benefit.

To me (just my personal opinion), the most reliable setup is one (known reliable*) AI transmitter and no other SPG. A spare SPG (or AI transmitter) would be in your kit, on the boat. A single AI transmitter is the least likely setup (other than no SPG at all) to have a failure that results in gas loss. At least, that's my perception. Any failure that does not involve gas loss is, to ME, just not that big a deal. As long as I have a backup I can switch to for the next dive, of course.

* My experience is with PPS transmitters, as used by Shearwater and others. I believe them to be very reliable. I have no opinion on other brands. My original transmitter is now 4 years old and has 200-ish dives on it and is still on the original battery. I would recommend to anyone to replace the transmitter battery per OEM specs, which is, I think at least once per year. I am still running mine with the original battery just because I have wanted to see how long it would actually last. And I haven't been using it for dives where having the battery die during the dive would be a real problem for me.

Thanks! Noted. I was thinking for the situation where the Vision fails (the computer or display portion) and I can no longer see the gas pressure. I would still have a wrist computer to continue the dive along with the attached SPG. Basically, there's no failure in measuring the gas pressure, just the ability to read it.

 

[JackD342]

That's great info to know. When I ordered my Deep6 reg, the SPG hose length was too short and I ended up getting a longer MiFlex from the local dive shop. Should the Vision's QD hose be too long or short, I can swap it out.

Removing the female QD connector requires a special tool. May not be able to swap the hose protector(s) too, for that “finished” look.

 

[stuartv]

Thanks! Noted. I was thinking for the situation where the Vision fails (the computer or display portion) and I can no longer see the gas pressure. I would still have a wrist computer to continue the dive along with the attached SPG. Basically, there's no failure in measuring the gas pressure, just the ability to read it.

Okay, I think that is a legit thought. My bad for my tunnel vision. I sometimes forget about sport diving in favor of thinking about things in tech diving terms. On a tech dive, if one computer died (e.g. your Vision), the dive would be over anyway, so the redundant SPG would serve no purpose. But, you make a valid point. On a sport (aka NDL aka recreational*) dive, if you have 2 computers and one dies, you don't automatically have to thumb the dive.

That said, even on a sport dive, I still would not take a redundant SPG in the water. I wouldn't do it with a primary pressure gauge being a physical SPG (and I've never seen anyone else diving 2 physical SPGs). And I definitely wouldn't bother with a physical SPG as an installed backup when I was using AI for my primary cylinder pressure gauge. But, this does seem like a somewhat legit consideration in favor of using hoseless AI over a hose-connected console. With hoseless, I can have 2 computers both reading the same transmitter, so if 1 computer dies, I still have my other computer AND can still see my cylinder pressure. With a hose-connected AI computer, if that computer dies, there is no other means to see the cylinder pressure (other than, as you say, another device, like an SPG, connected).

Also, one would hope that on a hose-connected AI console computer failures would be rare enough that the risk would not really merit installing a backup SPG just for the benefit of possibly saving one dive from having to be thumbed early. In my mind, you'd be trading off the insurance against ending a dive early because the computer died against the chance that the SPG has an issue and you have to end a dive early because of that. Sort of you're damned if you do and damned if you don't.

*I'm trying to avoid use of the term "recreational" because, in fact, tech dives are also recreational dives. But, there's no denying most people use the term "recreational dive" to mean a sport dive, aka a "no stop" or "no decompression" dive.