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Discussion Starter #1
Time for silly questions, which, as we all know, don't exist!!

I have been doing "accelerated deco" for a while now and after mch ribbing from Chasey and Paul Oliver I have come to think that I am doing something wrong. I have been using the tables that my Nautilus dive planner kicks out for me and have been typically been trying to dive on the best EANx mix I can get for dives in the 40m range, or air to 50m. My stage is usually filled with 50% and my grip on maths is not that strong......

I have been diving the most conservative tables for a while now whilst I try to get to grips with the programme and only recently managed to figure out deep stop into the equation. Sometimes when I have had no access to the computer I have been letting the Suunto Vytec plan my stops for me but these are so padded that I find I am spending far too much time in the water off gassing.

I posted a thread in the I learnt from that thread, and in that dive I ended up doing over 35-40 mins of stops on the vytec for a 27min dive to 43m.

The profiles the nautilus have kicked out vary from uber conservative (50 mins+) to very quick (for me) at just over 20-25 minutes.

I am thinking of starting to use the more aggressive profiles on tables with the computer in gauge mode but want to know some of the pitfalls and advantages that go beyond the obvious "i'll be out of the water quicker" that I can see at the minute.

All help appreciated!!
 

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aka Chimp 1 or Mavis...
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I posted a thread in the I learnt from that thread, and in that dive I ended up doing over 35-40 mins of stops on the vytec for a 27min dive to 43m.
The deco I would do for this dive on 21/35 and 50% would be 30mins from 21m to 6m and then 6min to the surface from 6m using RD.

Decoplanner on 20/85 using 26% and 50% gives 23 mins from 21 to 6m plus 6mins from 6m to the surface. The profile is [email protected], [email protected], [email protected], [email protected], [email protected] and [email protected] with 3m/min between 21 & 6m.

Therefore I don't think that 35mins is too excessive. The important thing is 'Do you feel okay when you get out?'
 

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DUE CEO, Booking agent, Coffee maker & Dogsbody...
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I am happy with the SUUNTO Deco, but then i am older, fatter and wiser ;) than you.

I like deep stops but my SUUNTO don't, i just carry on the penalty this gives i.e. It marks time during deep stops.

I do try to max my O2 for the depth and the Deco, as you have seen i have as rich a mix as i can get in my stage, 80% is my favorite, i don't like with a passion 100%, but anything from 50-80% will do.

I think most of your deco issues come on dive 2, try maxing the bottom gas O2 level for this, it may save some time and ribbing ;) :)

Please note i talk even more boll*cks than Chasey on Deco ;) :)

Of course if you work Chasey Ratio Deco you could do even longer :)
 

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Discussion Starter #4
I don't get it.

I just tried a 25 minute dive to 45m with 27% as my back gas and 80% as my stage gas, and I get to come out after a whacking: 48 minutes deco.

This is given as:

0 msl stoptime 16-Compartment-Buhlmann
45 msw 25min EAN 27
ascent 1min EAN 27
33 msw 1min EAN 27
ascent 0min EAN 27
27 msw 1min EAN 27
ascent 0min EAN 27
18 msw 3min EAN 27
15 msw 4min EAN 27
12 msw 5min EAN 27
9 msw 7min EAN 80
6 msw 27min EAN 80
0 msw 1min AIR

This is the sort of stuff I am trying to get away from. I know I have to do deco, but these numbers seem to be the total opposite of accelerated deco.
 

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Discussion Starter #5
If I try the same profile with the next most aggressive plan I come out with this:

0 msl stoptime HKBM
45 msw 25min EAN 27
ascent 1min EAN 27
24 msw 1min EAN 27
21 msw 2min EAN 27
18 msw 1min EAN 27
15 msw 4min EAN 27
12 msw 3min EAN 27
9 msw 2min EAN 80
6 msw 14min EAN 80
0 msw 1min AIR

27 minutes.....which seems a lot better but still longer than other people are doing - and I am not counting RB or trimix divers.
 

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Discussion Starter #7
The one I like the look of is this one:

0 msl stoptime VPM
45 msw 25min EAN 27
ascent 1min EAN 27
27 msw 1min EAN 27
21 msw 2min EAN 27
18 msw 2min EAN 27
15 msw 3min EAN 27
12 msw 4min EAN 27
9 msw 2min EAN 80
6 msw 11min EAN 80
0 msw 1min AIR

Now this is a nice quick profile. I am not bothered about the ribbing, just the amount of gas I am wasting doing unrequired stops, and the general novice feel to my deco planning.

Is doing a profile as agressive as this going to bend me silly?
 

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I dont do any diving at the moment that requires any planned deco and wont be until i've completed and passed a course, so my stupid question is why can you not use the ratio deco method as described by Garf??? (i think). Where you would have 25 mins of deco to do?
 

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I dont do any diving at the moment that requires any planned deco and wont be until i've completed and passed a course, so my stupid question is why can you not use the ratio deco method as described by Garf??? (i think). Where you would have 25 mins of deco to do?
Because he is using the wrong gasses.
 

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The important thing is 'Do you feel okay when you get out?'
This is what I'd be planning for...



The one I like the look of is this one:

0 msl stoptime VPM
45 msw 25min EAN 27
ascent 1min EAN 27
27 msw 1min EAN 27
21 msw 2min EAN 27
18 msw 2min EAN 27
15 msw 3min EAN 27
12 msw 4min EAN 27
9 msw 2min EAN 80
6 msw 11min EAN 80
0 msw 1min AIR

Now this is a nice quick profile. I am not bothered about the ribbing, just the amount of gas I am wasting doing unrequired stops, and the general novice feel to my deco planning.

Is doing a profile as agressive as this going to bend me silly?

So am I right saying this profile would save you about 13 minutes of stops on your previous plan. If we assume that these would be largely minimised stops at the shallower depths (say 6m for this example) then working on a SAC of 20L/Min then by my calculations you'd only be "wasting" about 150L of gas. It's not really an enormous amount... About 2% of your total supply (2x12's + 7L stage)

Obviously it's much earlier days in the world of deco for me but at present I'm happy to just try to make sure that I don't get a free trip on a helicoptor for the sake of saving that little gas or time.

Just my 2p's worth.

Si
 

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Silly question but cant you set the Vytec to be less conservative? or just accept that actually your probably safer by staying in the water that bit longer?

If you run tighter tables to me its like super chipping a car.

The manufacturers make a car with say 250bhp its tuned to run on any petrol station fuel which may not be that clean or perfect but the cars tuning takes this into account.

I can superchip my car to get 290bhp but this removes that margin of error, I have to make sure I put good fuel in the car and look after it maybe add octane booster.

Now to me the Vytec is running tables based on average Joe, maybe slightly overweight,maybe slightly dehydrated,maybe not an athlete. An Average car using average fuel..

You run tighter tables, you remove the "off day flexibility" so you have to be fit, you have to be hydrated, you have to have the stops perfect, you have to be in A1 shape. you have to run the car on good fuel.


Me id rather be safe, alive and feeling good, ten minutes extra in the water, so what, I like diving, I love being in the water, I want to live to come back and dive in again.


Granted I am saying this based on a handful of deco dives I have done although I am interested in reading about running aggressive / less conservative tables.


Davie
 

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I dont do any diving at the moment that requires any planned deco and wont be until i've completed and passed a course, so my stupid question is why can you not use the ratio deco method as described by Garf??? (i think). Where you would have 25 mins of deco to do?
Hi

Firstly, you would have 30 mins of deco to do as GLOC described, not 25. Or strictly speaking 27 rounded up to 30.

Secondly, he's on non-standard gases so he cannot use ratio deco as I described it.

Please be very very careful recommending ratio deco to someone not trained to do it. I was extremely careful to avoid doing this in my post and repeatedly stated it was there for informational use only.
 

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A short fat well off crap cave diver. Likes wrecks
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I would use Decoplanner on a conservitive setting of 10/85

Ascent rate 5m/min back gas 27%, 50% for deco

[email protected] Switch to 50%
[email protected]
[email protected]
[email protected]


Total Time to surface deco 21mins


Running streight Bhulman on 100/100GF this is 13mins deco so your padding by 30%


The deep stops dont show because the ascent rate takes care of them. Switch the same gas to 10m/min ascent and it adds deep stops


[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]



What ever this is an almost perfict ratio deco dive so the mental guide is 27mins on the bottom 27mins of deco. Its less for you as your using 27% not 21/35 but lets face it doing 27mins isnt going to hurt is it.


ATB

Mark Chase
 

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Discussion Starter #16
Hi,

where did that profile come from?

Cheers,

Mark.
The profiles all come from Nautilus dive planner.

Also: What gases should I be using if you say I am using the wrong ones? I am not the only diver on 27% nitrox down there, so why is my EANx wrong and everyone else's OK?

My deco just seems longer in comparison to everyone I dive with.

I know shaving time off puts me more at risk, and that is why I am not going to use the insane looking US Navy tables option. What I am talking about is cutting the 45-50 minutes that the vytec gives me to the more acceptable 25 minutes that most of my buddies seem to be doing.
 

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Also: What gases should I be using if you say I am using the wrong ones? I am not the only diver on 27% nitrox down there, so why is my EANx wrong and everyone else's OK?
You're not using the wrong gases per se, it's just that they're wrong for using the Ratio Deco outlined by GLOC.
 

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aka Chimp 1 or Mavis...
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What I am talking about is cutting the 45-50 minutes that the vytec gives me to the more acceptable 25 minutes that most of my buddies seem to be doing.
Dive tables then and not the Vytec. Or rather dive the Vytec in guage mode and have deeper/longer etc plans for the 'what if...' occasions. 26% is the correct gas (if using Nitrox) for this depth assuming a max ppO2 of 1.4 but 1% isn't going to make a massive difference in your deco.

The issue which I think Paul is alluding to is the second dive I presume is being conducted on the Vytec and to a similar depth which means it will be penalising you for the first dive. Use tables, correct ascent rates, a decent SI (2hrs or +) and then your second dive should be much shorter :)

The wrong ones alludes to the fact that GUE use Trimix below 30m - 21/35 until 48m and then 18/45.
 

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Also: What gases should I be using if you say I am using the wrong ones? I am not the only diver on 27% nitrox down there, so why is my EANx wrong and everyone else's OK?
I don't think that the gas choice is "wrong" it has just been pointed out that 27% will not work with ratio deco - see appropriate instructor for details :)
27% would be a little "hot" for my own personal taste as it gives a PPO2 of 1.49 at 45m, for nitrox I'd go for 25% to bring it under 1.4 - but that's just my own preference.

My deco just seems longer in comparison to everyone I dive with.

I know shaving time off puts me more at risk, and that is why I am not going to use the insane looking US Navy tables option. What I am talking about is cutting the 45-50 minutes that the vytec gives me to the more acceptable 25 minutes that most of my buddies seem to be doing.
Ok, stupid question on my part so please try not to feel insulted - are switching the gas on the Vytec? I've had the Vytech showing 40+ mins but when I switched to 50% at 21m this has dropped to 20+ mins.

Having said that I tend to run tables cut on V-Planner (+2 conservitism) as it gives a much nicer profile and is better in some instances (such as when you were diving on 32% & 80% the day before and forget to change the gasses :embarassed: )

At the end of the day it's not a race and do what you need to do to get you out of the water feeling good.

Just my thoughts
 
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