Deco on the Fly....

[MATTBIN]

Blurb sent.

Matt

[chrisch]

I know Suunto have recently beefed up the RGBM aspect of their algorithm and the latest Vytec has the deep stop stuff in it. However, since there isn't really enough empiric data on "non standard" profiles its hard to see how the computer can "control" it.

The Suunto and its algorithm remain the decometer of choice for me for no stop or short stop but for planned stop dives I still prefer a PC based package.

My worry would be that a non-standard (eg saw-tooth) profile could result in deco that the diver has not got enough gas to complete. Even therefore if the decometer gives adequate stops the diver cannot make them.

Chris

[Colin Marriott]

Originally Posted by chrisch

I know Suunto have recently beefed up the RGBM aspect of their algorithm and the latest Vytec has the deep stop stuff in it. However, since there isn't really enough empiric data on "non standard" profiles its hard to see how the computer can "control" it.

The Suunto and its algorithm remain the decometer of choice for me for no stop or short stop but for planned stop dives I still prefer a PC based package.

My worry would be that a non-standard (eg saw-tooth) profile could result in deco that the diver has not got enough gas to complete. Even therefore if the decometer gives adequate stops the diver cannot make them.

Chris

And how does pre-cut tables solve this situation?

ColinM

[chrisch]

I doesn't.

My concern is simply that people would use the decometer to monitor dodgy profiles and think they are "safe". best not to follow such profiles at all and therefore I am curious to know if the idea of the Suunto modifications are designed to prevent the problem.

Its a difficult thing to debate without the data and its OT too.

Chris

[Finless]

No, I would not use deco on the Fly, I have a dive computer which tracks my profile accurately and then fudges some figures for me. I haven't got bent in 20 years (that I am aware of) so why bother?

I would accept it would be very useful skill to have as a backup, however, as my memory for such things isn't that good then .......

If doing a deco dive I almost always prepare a backup slate for use with my bottom timer if the computer goes to sleep.

With ref to plan the dive/dive the plan .... what happens if you get on a wreck and all the good stuff is at the deepest depth when you planned only to spend 5 minutes there? If you trust your computer then it is fairly simple to spend longer at the deepest depth and adjust the rest of the dive accordingly (don't know if the same applies for trimix).

Does doing deco "on the fly" limit your mixes (due to the mental calcs being simpler)? What happens if something goes badly wrong and you lose track of time and depth? Why run the risk?

If EVERYTHING failed then I guess I would ascend as safely as possible and just hang at 9m, 6m, 3m until I'd nearly used all my gas and hope that was enough.

Of course, my statement is from a point of relevant ignorance as I do not have the knowledge of deco theory that many do. All I can say is it has worked for me so far and I see no reason to change.

[MATTBIN]

Originally Posted by chrisch

I know Suunto have recently beefed up the RGBM aspect of their algorithm and the latest Vytec has the deep stop stuff in it. However, since there isn't really enough empiric data on "non standard" profiles its hard to see how the computer can "control" it.

The Suunto and its algorithm remain the decometer of choice for me for no stop or short stop but for planned stop dives I still prefer a PC based package.

My worry would be that a non-standard (eg saw-tooth) profile could result in deco that the diver has not got enough gas to complete. Even therefore if the decometer gives adequate stops the diver cannot make them.

Chris

Well, saw tooths are a no-no anyway (or at least that's what Whipps Cross told me ). How would a saw-tooth result in not enough gas, you would plan a max bottom depth and a max bottom time, this would then give you an ascent profile and you'd base your ascent gas requirements on that, if you saw toothed you'd actually have less max depth/time than planned (on paper) so you'd ascend when you hit max bottom time. If you are saying you'd follow the computer rather than your dive plan then I'd agree you could get yourself (and your buddy) into big trouble. A conservative dive plan would of course have double ascent gas.

Matt

[Colin Marriott]

Pity this is in the DIR forum ....


ColinM

[Finless]

Originally Posted by MATTBIN

Well, saw tooths are a no-no anyway (or at least that's what Whipps Cross told me ). How would a saw-tooth result in not enough gas, you would plan a max bottom depth and a max bottom time, this would then give you an ascent profile and you'd base your ascent gas requirements on that, if you saw toothed you'd actually have less max depth/time than planned (on paper) so you'd ascend when you hit max bottom time. If you are saying you'd follow the computer rather than your dive plan then I'd agree you could get yourself (and your buddy) into big trouble. A conservative dive plan would of course have double ascent gas.

Matt

Didn't they become extinct centuries ago?

[Finless]

Originally Posted by Colin Marriott

Pity this is in the DIR forum ....


ColinM

Oh FFS, I never noticed! Just ignore my posts as normal. I have just committed tautology .... there was no need to post this!

[chrisch]

Originally Posted by Colin Marriott

Pity this is in the DIR forum ....


ColinM

Start over elsewhere - there's plenty of interest.

Chris