Dive Computer Alarms: should we even have them?

[doctormike]

Yes, and as I read the post I was replying to, it was more of a general question about computer alarms.

And the title of the split-off thread I replied in is "Dive Computer Alarms", not "Tactile dive computer alarms".

Right, just giving you the context in case you hadn't seen the original thread. Some of the answers may reflect that.

You said that they had no function for you because you can't hear them. But not all alarms are audible.

 

[GF99/99]

I can give you both, multiple reasons

1. Currents (obv something Maries doesn't come into contact with)

Ascent alarms can give you the first indication of an upwelling that you might not "see" especially when you can't see the bottom

In a downcurrent washing machine - your spatial awareness can be temporarily disabled - ascent alarms give you an indication of travel

Coming off a reef (in current) - and needing to shoot your dsmb pronto. Ascent alarms can be of value

In proper current when it's all going a bit south you are somewhat task/bandwidth loaded staring at yoru computer might be low on the list of immediate priorities

For reference I probably engage in 10 or so significant down currents per year at least once a year it's heart thumping event.


2 Training and rescue

More than once I (as a Guide/instructor) have had to take control of divers on their ascent - my hands are full, so ascent alarm provides immediate feedback while I'm engaged in other more pressing issues

Similarly on Rescue courses, when I'm the victim - if my alarm goes off on the ascent, the student is briefed to stop and restart (on the deeper exercises)

So that's a couple of real world example without even thinking of it

I am going to have to side with the group that is "pro alarms" (but under the stipulations that I do hate audible alarms I think these should not be allowed underwater and honestly I don't think I would feel the vibration alarms but I have never tried them) but I do think alarms can come in handy.

My reason/the alarms I like are:
-- Low battery alarm (especially for transmitters) always nice to get a reminder that your battery is low. I like this a lot I think this is my favorite alarm out of any alarm. If I could only have one alarm on my computer it would be this one.

-- High CNS alarm. Yes I don't need this and yes when I plan longer deep dives I am fully aware of my end CNS but I don't keep CNS on my main display so I have to scroll to find it so its nice to have that 80% pop up on your screen once you hit it. Especially since this is not something your constantly monitoring or checking and generally on most dives your never hitting 80% so its not something you looking out for. Its only 140m + dives or really long bottom times at 80m-100m when I start going over 80% so I like having it pop up.

-- Po2 alerts/buddy alerts on HUD's. I like these its nice to see your own or your buddy's computer and HUD flashing red.

-- This one is very questionable defiantly don't need it but I have it turned on. I like having a stack time warning, yes I don't need it and I am aware of my scrubber duration and this is all taken into account during the dive plan but its just a nice friendly reminder when you have 30min left.

 

[Storker]

not all alarms are audible

I missed mentioning that my PDC is on my HP hose, so a tactile alarm might, if possible, be even less useful than an audible alarm.

 

[doctormike]

-- Po2 alerts/buddy alerts on HUD's. I like these its nice to see your own or your buddy's computer and HUD flashing red.

Seen this?

 

[cipherbreak]

We increasingly have poka-yokes on every other aspect of life--even for far less dangerous undertakings.

Even though I think the color codes on my Perdix AI are sufficient to me wrt tank pressure, PPO2, and GTR, it is not in keeping with almost every other piece of technology humans operate which provide at a minimum visual + audible alarms.

 

[scubadada]

Use of alarms is a personal choice. With my hearing loss, I don't hear any audible alarms. Other people's do not bother me, they do seem to bother divers with normal hearing quite a bit.

I've been diving an Oceanic computer for 18+ years, I've never had the audible alarms on. I have specifically dived a VT3 for the last 10+ years, it has some visual alarms for important features. Most of the alarms it has are inactivated. I've been diving a Shearwater Teric for the last year and a half. I have both the audible and haptic alarms turned off. It also has visual alarms for important features. I pay an appropriate amount of attention to my computers and don't need alarms. The visual alarms I get are all expected

 

[OTF]

Let's say you drop something really important, like your beloved $6000 camera rig. Watching it plunge down into the depths you make the split second decision to swim after it. It'll only take a minute to catch. Current is high and vis is low. You're not panicking, but it's suddenly a high stress situation. You're checking your computer and tell yourself you won't exceed X depth or PO2, but your anxiety and determination to catch the camera builds. So does the CO2 in your system, and the creeping effects of narcosis. Your tunnel vision is locked in to catching that camera. It has all your trip pictures on it. Maybe you descend faster than you think. Maybe in the fog of battle you forget to check your computer as often as you should. Maybe you greatly exceed MOD, or burn through lots of gas, or learn what "dark nark" really means. Maybe you pass out and die, as other divers have died in this same circumstance. Or maybe a LOUD AND VIBRATING PO2 ALARM goes off, helping your narked brain snap out of this bad impulsive idea and go up.

Of course a clear headed, highly experienced diver who always makes the right choices (like yourself, dear reader) would never end up in this scenario. But maybe the dingus next to you on the dive boat would. Obnoxious alarms can save lives.

 

[GF99/99]

Seen this?

Wow! nice video, yup that's the waring I like. seen this be for not that high but I dive a JJ predominantly and that's the one flaw is the MAV's with 4 S80 bails out's on that is a lot of stuff congregated around your D-rings (I have never dove front mounted CL but it sounds even worse) and the MAV's are really easy to bump amongst all this stuff I have also found they get sticky really easily; always exciting when you have a free flowing MAV. Especially the dil side if your doing lots of dil switches I usually have to clean and re-grease these things all the time.

I guess the one plus thing out of this is at least he knows his cells are not current limited

 

[Blackcrusader]

Let's say you drop something really important, like your beloved $6000 camera rig. Watching it plunge down into the depths you make the split second decision to swim after it. Of course a clear headed, highly experienced diver who always makes the right choices (like yourself, dear reader) would never end up in this scenario. But maybe the dingus next to you on the dive boat would. Obnoxious alarms can save lives

Common sense without an alarm can save lives but I am all for others using audio alarms or what ever alarms they want. The Perdix has alarms but you need to be paying attention to see them

If your camera us so important why don't they have a safety line to the camera rig in case you drop it. I have a long sports shoe lace to my rig. It has come in useful. One lass on a morning dive dropped her camera rig, she watched it go to the depths where the sea bed was from around 40m - 50m on a slope. I was doing the same dive site my next dive 30 mins later so I said I would go look for it. Her guide told me where she lost her gear and I know the dive site. I retrieved it at 45m depth. I went with an instructor who I have dived with many times but he just waited at 40m as I got the camera. So even on air it was just watch NDL and pay attention. As this was right at the beginning of my dive it was on a full tank.

So she made a good decision not to chase her camera. She was hoping it wasn't damaged and also was still there when I went. Fortunately in that area not many divers go deeper than 30m. The site can have some fun down currents and I've done some nice drift dives there. That day was a dive against the current to get the camera then with the current to join the group. As you can see by the time I got the camera I still have 180 bar left. The instructor and I were first off the boat and later joined up with other divers from our boat after 20 minutes or so. Finished the dive after 70 minutes with 60 bar left.

If a diver is not narced and drop some gear they need to make a choice. Of course you can ask others to get your gear perhaps on another dive. I've seen guides and divers pick up dropped camera's and give it to our diver center manger who then makes sure it's not from out divers, then contacts are dive shops in the area. Some people like me have their name and whatsapp number on a sticker on the gear. I find most people to be pretty honest and return gear.

If you drop gear and really take off after it how fast can you descend in a minute? 50m or more?

 

[doctormike]

I dive a JJ predominantly

Excellent choice!