Do you rely on your computer to conduct a dive safely?

[nickb]

I was catching up on some old episodes of Seaside Rescue the other night and I saw one with a ‘Diver with the bends’ section.

The voiceover introduced the story by announcing that, due to a malfunctioning dive computer, a diver had missed 25 minutes of stops after diving to 35m for 45 minutes. Unsurprisingly, he had to be choppered off to the pot.

I was initially quite surprised that someone could be that dependant on a computer without having some idea that they’d need at least 25 minutes of deco, assuming ideal backgas and no deco gas. But I later realised that, as a dived-up BSAC Sport Diver, I was qualified to dive to that depth without having to know that sort of detail and without being accompanied by someone with more experience. It was only when I started to undertake ‘techie’ training that I really began to understand any of the underlying theory.

Having said that, my planning before the dive would have given me some idea what to prepare for; gas & deco wise

What would others do, if their computer packed up during a dive? Would you be confident that you could get out of the water safely?

[John Touhig]

I use a VR£ but at the end of the day its just another tool. The dive would have been pre-planned on VPlanner for depths, run times, gas etc and a set of tables produced and carried on the dive. I would always have a backup timer/depth gauge, plus my buddy would also have both so we have a fair bit of redundancy between us.


The only time I dive with just a computer is on holiday and these dives are always <30m and always no stop dives. If the computer died on the dive I am confident that I could ascend at a sensible rate...


John

[MartyC]

Used to rely solely on the computer, now I use tables, most inland site bimbles I use the computer in guage mode and use min decompression data ala GUE .
Sea dives I will use tables and bottom timer with a computer as back up.

[BigG]

Yes - but not a fair response as I don't (yet) do deco* but:

my sport diver training says to use a planning table (the one that comes with the BSAC tables).

so as soon as I get into deco training / doing - I'll either have this slate or a wrist mounted slate on me with the deco requirements on. So if computer says nooooo.. I should (hope to) be ok

G

* Im also only on a single 12 so can't do much if i try

[Lazlo]

Interesting.

1st - Leaving aside the POV that says all dives are deco..., I think that any diver who does a course providing formal deco stops really ought to already have a rough idea of when deco will be required - i.e. they should be instinctively aware of the NO-STOP times for various depths. If they're not experienced enough to realise that (to use your example) 35m for 45 minutes requires significant deco, then they've no place doing the dive in the first place. Such divers should restrict themselves to NO-STOP dives. Also, such divers really weren't paying much attention when the tables were taught.

2nd - What would I do? Well, if I've not done any special planning, then it's definitely going to be a no-stop dive, with maybe just a few minutes deco, say less than 10 minutes. Then, because I didn't really plan it, I'd be relying on my computer. If the computer failed, then I ascend. Carefully. If the computer gives me a strange reading, like no deco required after about 20 minutes(ish) at 35 metres (on air), then I know the computer has failed. I wouldn't do a dive with significant deco where I didn't have a backup plan for when the computer fails.

[warmwaterdiver]

Originally Posted by nickb

I was catching up on some old episodes of Seaside Rescue the other night and I saw one with a ‘Diver with the bends’ section.

The voiceover introduced the story by announcing that, due to a malfunctioning dive computer, a diver had missed 25 minutes of stops after diving to 35m for 45 minutes. Unsurprisingly, he had to be choppered off to the pot.

its one thing having a computer, another being able to read it

I use two VR3's as you know, but always run it through Vplanner just to see what kind of stops I'm likely to be doing and what kind of RT to expect

if I loose my buddy, and both VR3's fail then I'm having a bad day, and will just do as much deco as I can on the gases I've got

3 divers did a similar thing on the Elk out of Plymouth last year (or the year before?) IIRC, 35m down for 30mins+ and didn't have enough gas for deco (backgas cylinders only divers)

[Finless]

Originally Posted by nickb

What would others do, if their computer packed up during a dive? Would you be confident that you could get out of the water safely?

Yes.

If my bottom timer packed up as well whilst I was into deco then I would have guestimated as best I could and hang at 3ish mtrs until lack of gas or boredom drove me to the surface. Assuming I had no buddy present.

[milldog]

I'm a great believer in the "one pink elephant two pink elephant" deco system and thats if the VR3 goes tit's up loose my mate (if i have one ) and i cant find tricky to mug for his computer

however i know how to do ratio deco and have a Poseidon watch

Graham

[NotDeadYet]

I generally do a table for any deco diving. I've got a Shearwater which is a double check underwater but I normally stick to the table.

No deco diving then I just use a timer (which I always carry anyway).

[MonkeyPony]

All my deco dives are done on run times with an A and B plan (and sometimes a C). I generally also use my vytec and go with the one that is more conservative on the stops but I know exactly how much deco I'm going to be doing and when I'll be doing it before I hit the water.

Within my BSAC club however, I am the only one to conduct deco like this. The general norm seems to be falling off the back of the boat with the intention of 'doing a few mins of deco' and using the computer (and no backup).