Dive Timer with Multiple Alarms

[John Touhig]

Guess I opened a can or worms by asking, on reflection, a stupid question.

I should have engaged by brain before allowing my fingers to do the walking...

GM

[Andy Phillips]

Originally Posted by Mark

Basically, you don't. Don't lose your buddy EVER and carry a spare mask.



Have you been trained in and practiced no-mask DSMB deployment and controlled no-mask ascents? I rather think not. Have you ever done a no-mask ascent from depth? How about from 6m? I doubt it. It is an extremely intimidating experience even when you have an trusted and very highly skilled buddy to help you. The best you could hope for would be to reach the surface (with or without your buddy).

Having a stupid extra beeper on your computer would be a total watse of time. You would almost certainly trigger the rapid ascent alarm and would be unable to work out what it is trying to tell you. Beep, beep, beep, beep ,beeep, beep.......all the way to the surface.

Regards,

Mark

Eh up Mark,

We agree entirely, flipping heck, it does happen.

Andrew

[Andy Phillips]

Originally Posted by GasMuncher2

Guess I opened a can or worms by asking, on reflection, a stupid question.

I should have engaged by brain before allowing my fingers to do the walking...

GM

I think it is Bren who keeps saying "the only stupid question is the question you don't ask"

The purpose of a site like this is to inform and entertain, the reason this particular site is so successful is that 99% of the time it manages to do just that.

Keep asking,

All the best,

Andrew

[alunharford]

Originally Posted by imported_andyp

I get your point, but, I think you have to accept there is risk.

My problem is in whether this increases or decreases that risk. There's always going to be a risk, whatever you do.

Originally Posted by imported_andyp

If you go deep, you have a backup mask, in fact, all essential pieces of equipment are duplicated.

I thought there was some debate on whether you should duplicate a mask, but I'm probably wrong.
Even so, if you've lost your other one you are reasonably likely (5% of the time maybe) to drop the spare because you can't see what you're doing.

Originally Posted by imported_andyp

A computer that just beeped at gas switch depth would be of little use, how would you know when to stop at each stage of the deco.

I'm pretty sure I could judge distance well enough. I have at least a reasonable idea of how big a metre is and could get it right +/- 10cm. Doing the deco below your first gas switch could be a problem, but providing it's not a huge length of time I would have thought you could get it *about* right (right enough to come up bent instead of dead).

Originally Posted by imported_andyp

Plus, how would you see to send it up. A self inflating blob would give you a chance, just not much of one.

Oh come on, even I probably send up a blob without being able to see it probably 75% of the time (never tried it mind, so it might be more difficult than I think). You might get caught on it, in which case you're almost certainly dead, but assuming that doesn't happen you've got at least two tries.

Anyway, my point is that it COULD help (no matter how remote the chances), and that I can't think of a drawback (other than perhaps using some battery life on your computer, but I think it's fair to say that's even less of a problem.

[Mark Powell]

Originally Posted by alunharford

I'm pretty sure I could judge distance well enough. I have at least a reasonable idea of how big a metre is and could get it right +/- 10cm. Doing the deco below your first gas switch could be a problem, but providing it's not a huge length of time I would have thought you could get it *about* right (right enough to come up bent instead of dead).


Oh come on, even I probably send up a blob without being able to see it probably 75% of the time (never tried it mind, so it might be more difficult than I think). You might get caught on it, in which case you're almost certainly dead, but assuming that doesn't happen you've got at least two tries.

My only advice would be to give it a try (in a safe environment with a good buddy).

Both of these are much harder then you might think. The only way to be sure that you are going to be able to do this for real is to practice. In the thread above there are a number of experienced divers who have said that it's difficult, requires practice, etc. They are speaking from experience.

When I teach tech courses people often say that they carry a spare mask, DSMB, etc. I always get them to fit the spare mask (at a shallow depth) and deploy their spare DSMB. Very often they find it very hard the first time as they have never tried it before. By the end of the course they can fit a backup mask and send their backup DSMB with no problem.

You don't want the first time you try something to be the time when things are starting to go wrong.

[Andy Phillips]

OK, this is now getting silly so this will be my last post on this thread, well certainly on this subject.

1) Whether or not it beeps will not make the slightest bit of difference, so pointless

2) Drop the Mask, no, we practise things like this reasonably often, the idea is to not drop it, you are making up arguaments to support what is becoming an untenable position, please stop it.

3) Are you seriously saying that you can judge a 3M distance (generally speaking this is your distance between stops) when you are 60 ~ 70M underwater with no visible means of reference without a mask, somehow I think not.
Oh and don't forget you might just be feeling a tincy wincy bit stressed. This is a terrible thing to try and do, even when you are training and you know there are competant people in the water who know that you are going to attempt to do it.

4) OK, try unclipping, unraveling, inflating and sending it up without opening your eye's, no cheating at all. Yes it is possible, but a right royal pain in the a**e.

I am not being funny, but it is obvious you have not tried any of this, I don't wish to get into an arguament so please accept I will not discuss it anymore.

All the best,

Andrew

[alunharford]

Originally Posted by imported_andyp

OK, this is now getting silly so this will be my last post on this thread, well certainly on this subject.

Well I'll keep going anyway in the hope that I might learn something.

Originally Posted by imported_andyp

Are you seriously saying that you can judge a 3M distance (generally speaking this is your distance between stops) when you are 60 ~ 70M underwater with no visible means of reference without a mask, somehow I think not.
Oh and don't forget you might just be feeling a tincy wincy bit stressed. This is a terrible thing to try and do, even when you are training and you know there are competant people in the water who know that you are going to attempt to do it.

Skip all the stops below your next gas switch. You then know your depth (assuming you didn't know your depth before). Feel out 1m. Reel it in. Repeat three times. So you could well get bent as a result, but I don't see that this is any worse than "It's not worth bothering - you're dead!"

[Andy Phillips]

Try it

Andrew

[alunharford]

Originally Posted by Mark Powell

My only advice would be to give it a try (in a safe environment with a good buddy).

Both of these are much harder then you might think. The only way to be sure that you are going to be able to do this for real is to practice. In the thread above there are a number of experienced divers who have said that it's difficult, requires practice, etc. They are speaking from experience.

When I teach tech courses people often say that they carry a spare mask, DSMB, etc. I always get them to fit the spare mask (at a shallow depth) and deploy their spare DSMB. Very often they find it very hard the first time as they have never tried it before. By the end of the course they can fit a backup mask and send their backup DSMB with no problem.

You don't want the first time you try something to be the time when things are starting to go wrong.

I'm talking about the "general diver" rarther than me!
There are divers who could do it (I certainly wouldn't like to have to).
There are also divers who know what the bleeps coming from their dive computer mean.
Divers that fall into those two groups might be better off with it.

Anyway, ignore that - I'm trying to get information by playing devil's advocate and it isn't working. I'll try another method.

I agree that my agruments for it are far from strong (they were never meant to be - it was just an example) - my point is that I can't think of an argument AGAINST it, not that I think it's an essential piece of kit that everybody should carry!

[iainmsmith]

Originally Posted by Mark Chase

Hmmmmmm make up your mind, Standard gasses are expensive, If your using 18/45 on a 50max dive like the Moldavia your paying £48.oo for the gas (at my local prices) where as I am on 23/25 paying £26.00 isn’t THAT an expensive way to dive?

-snip-

Originally Posted by Mark Chase

Tables are OK but the anti computer arguments predate the latest units like the Abyss and the VR3. Its 2004 boys and girls computers are here to stay.

I don't see a contradiction. Standard/"Sensible" gases for those depths are expensive. They are also, IMO, essential for safety. They add considerably to safety and enjoyment. IMO, the same is not true of an expensive computer. Again, IMO, a technical dive should be planned down to the n'th detail before getting in the water - there isn't the same room for ad libbing that there might be on a recreational dive.

Perhaps with great experience and a true understanding of how variation from a rigid plan affects gas turn points, gas reserves, deco profiles, lost gas situations, etc, there might be room for "flying by wire" on a computer, but until one reaches that point, the discipline of planning and executing the dive should be sufficiently rigorous, to the extent that a computer adds nothing to the execution of the dive.

(For context, I have limited trimix experience - three years since qualification, probably still fewer than 50 mix dives, to 55m max, up to two deco gases. I very much put myself in the position of a trimix novice and firmly believe that I'm nowhere near experienced enough to be doing anything other than planning the dive and diving the plan. However, I've been doing accelerated deco dives for a few more years than that...and still approach them in the same way. I accept that my views may change in due course.)

Iain