Deco Profile

Chris Armstrong · September 10th, 2007, 01:15 PM

Hi All,

I'm planning a dive on the USS Oriskany, Florida in summer and I have come up with a deco schedule. I'd like some comments / criticisms of my schedule ...

45m for 35 mins on air
30m for 15 mins on 32% nitrox
20m for 5 mins on 36% nitrox - deep stop
9m for 5 mins on 36% - deco stop
6m for 20 mins on 36% - deco stop
3m for 5 mins on 36% - deco stop

I've got this profile shape from the BSAC '88 tables when diving air. I've padded it out a bit more with extra deco stop time. AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule.

Thoughts people?

**neilh** · September 10th, 2007, 01:19 PM

Quote: (Originally Posted by cancerchris)

I'd like some comments / criticisms of my schedule
...
45m for 35 mins on air
...

Personally I'd avoid this for starters!

Is there a reason for not using trimix for this dive?

MonkSeal · September 10th, 2007, 01:55 PM

Quote: (Originally Posted by cancerchris)

AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule.

Thoughts people?

We don't use one set of gases and pretend to use another. For this dive we would use trimix (21/35 or 18/45) and nitrox 50 (and maybe oxygen in addition, depending if this 35 min at bottom is really 35 min).

Retardboy · September 10th, 2007, 02:08 PM

Well, my planner gives almost twice the decotime you have planned..

Martin Burnard · September 10th, 2007, 02:36 PM

Ive just been a volunteer in a chamber doing some test on air for some research (can't give details at present.... not allowed!) but suffice to say it very strongly reinforced my opinion on the need for trimix.

I was unaware of the depth during the tests, but when I saw the results compared to how I performed on the surface......

See the standards are there for a reason.

vid · September 10th, 2007, 02:46 PM

Quote: (Originally Posted by cancerchris)

Hi All,

I'm planning a dive on the USS Oriskany, Florida in summer and I have come up with a deco schedule. I'd like some comments / criticisms of my schedule ...

45m for 35 mins on air
30m for 15 mins on 32% nitrox
20m for 5 mins on 36% nitrox - deep stop
9m for 5 mins on 36% - deco stop
6m for 20 mins on 36% - deco stop
3m for 5 mins on 36% - deco stop

I've got this profile shape from the BSAC '88 tables when diving air. I've padded it out a bit more with extra deco stop time. AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule.

Thoughts people?

Chris
Not sure that the BSAC tables are an appropriate starting point for your own devised schedule. They were written with a specific purpose in mind and whilst better than what we had before '88 - gas theory has moved on a bit in the interim.

For some air wouldn't be the first choice for BG (even BSAC now advocates trimix below 40m).

There's probably little benefit in carrying both 32% and 36% - the difference in deco time is marginal.

Your profile suggests you're a PADI AOW with 30 dives, in which case this dive may be beyond your current training/experience.

keep safe

vid

Devon Rob · September 10th, 2007, 03:01 PM

If I were you I´d take Oxygen with you as well. LOTS!

Seriously though, your choice of gasses is.. erm, how can I put it... errr....interesting! yes, that´s it interesting!
You really should get a lot more experience and training before even thinking so far ahead.
It´s good to have a goal though, best of luck with it! :-)

Leigh u · September 10th, 2007, 03:40 PM

yes with that profile I would bring a lot of oxygen...
but hitting the nail on the head..get some training..this is an offshore dive and this kind of profile is not at your current "training" level.

If you were deco trained..this would still be an awful profile..and will most likely leave you feeling like you have the flu.

amascuba · September 10th, 2007, 06:27 PM

This is a scary profile. Have you been trained for deco diving? I wouldn't do the profile that you prescribed at all.

Marijn · September 10th, 2007, 06:46 PM

Although i'm pretty much a tenderfoot in deco-country.

GAP predicts trouble when diving a schedule like this one.

Using the gasses like you planned, GAP gives an additional 25 minutes on O2@3meters.

And this is using Buhlman ZH-L16-b GF20/70 (info for what its worth, if my info stinks, plz tell me)

September 10th, 2007, 02:36 PM	#5 (permalink)
Martin Burnard(Offline) New Member Join Date: Nov 2005 Location: Plymouth, UK Posts: 616	Ive just been a volunteer in a chamber doing some test on air for some research (can't give details at present.... not allowed!) but suffice to say it very strongly reinforced my opinion on the need for trimix. I was unaware of the depth during the tests, but when I saw the results compared to how I performed on the surface...... See the standards are there for a reason. __________________ I once enjoyed a sado-masachistic frenzy of total tintintabulation leading to a state of metampsychosis... or did I make that up? www.bananafrogcars.co.uk

September 10th, 2007, 03:01 PM	#7 (permalink)
Devon Rob(Offline) not a new member Join Date: Mar 2006 Location: Lyme Bay.Devon.UK formerly Hamburg, Ger. Posts: 538	If I were you I´d take Oxygen with you as well. LOTS! Seriously though, your choice of gasses is.. erm, how can I put it... errr....interesting! yes, that´s it interesting! You really should get a lot more experience and training before even thinking so far ahead. It´s good to have a goal though, best of luck with it! :-) __________________ this mail was checked for viruses,worms & bad breath

September 10th, 2007, 03:40 PM	#8 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 240	yes with that profile I would bring a lot of oxygen... but hitting the nail on the head..get some training..this is an offshore dive and this kind of profile is not at your current "training" level. If you were deco trained..this would still be an awful profile..and will most likely leave you feeling like you have the flu. __________________ http://youtube.com/wegodown

September 10th, 2007, 06:46 PM	#10 (permalink)
Marijn(Offline) Smurf #1 Join Date: Aug 2007 Location: Papendrecht, The Netherlands Posts: 549	Although i'm pretty much a tenderfoot in deco-country. GAP predicts trouble when diving a schedule like this one. Using the gasses like you planned, GAP gives an additional 25 minutes on O2@3meters. And this is using Buhlman ZH-L16-b GF20/70 (info for what its worth, if my info stinks, plz tell me) __________________ Its a fact that the humans can't go without water for more than 3 days

September 10th, 2007, 01:15 PM	#1 (permalink)
Chris Armstrong(Offline) Banned Join Date: Aug 2007 Location: Eltham(London)/ Loughborough(Leciestershire) Posts: 591	Hi All, I'm planning a dive on the USS Oriskany, Florida in summer and I have come up with a deco schedule. I'd like some comments / criticisms of my schedule ... 45m for 35 mins on air 30m for 15 mins on 32% nitrox 20m for 5 mins on 36% nitrox - deep stop 9m for 5 mins on 36% - deco stop 6m for 20 mins on 36% - deco stop 3m for 5 mins on 36% - deco stop I've got this profile shape from the BSAC '88 tables when diving air. I've padded it out a bit more with extra deco stop time. AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule. Thoughts people?

September 10th, 2007, 01:19 PM	#2 (permalink)
neilh(Offline) Wreck Enthusiast Join Date: Nov 2005 Location: Barnsley, UK Posts: 2,667	Quote: (Originally Posted by cancerchris) I'd like some comments / criticisms of my schedule ... 45m for 35 mins on air ... Personally I'd avoid this for starters! Is there a reason for not using trimix for this dive?

September 10th, 2007, 01:55 PM	#3 (permalink)
MonkSeal(Offline) New Member Join Date: Feb 2006 Location: Zagreb, Croatia Posts: 575	Quote: (Originally Posted by cancerchris) AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule. Thoughts people? We don't use one set of gases and pretend to use another. For this dive we would use trimix (21/35 or 18/45) and nitrox 50 (and maybe oxygen in addition, depending if this 35 min at bottom is really 35 min).

September 10th, 2007, 02:08 PM	#4 (permalink)
Retardboy(Offline) New Member Join Date: Aug 2006 Location: Norway/Trondheim Posts: 48	Well, my planner gives almost twice the decotime you have planned..

September 10th, 2007, 02:46 PM	#6 (permalink)
vid(Offline) New Member Join Date: Nov 2005 Location: london/surrey border, UK Posts: 356	Quote: (Originally Posted by cancerchris) Hi All, I'm planning a dive on the USS Oriskany, Florida in summer and I have come up with a deco schedule. I'd like some comments / criticisms of my schedule ... 45m for 35 mins on air 30m for 15 mins on 32% nitrox 20m for 5 mins on 36% nitrox - deep stop 9m for 5 mins on 36% - deco stop 6m for 20 mins on 36% - deco stop 3m for 5 mins on 36% - deco stop I've got this profile shape from the BSAC '88 tables when diving air. I've padded it out a bit more with extra deco stop time. AND By using nitox gases that would accelerate off gasing, but sticking with an air deco schedule. Thoughts people? Chris Not sure that the BSAC tables are an appropriate starting point for your own devised schedule. They were written with a specific purpose in mind and whilst better than what we had before '88 - gas theory has moved on a bit in the interim. For some air wouldn't be the first choice for BG (even BSAC now advocates trimix below 40m). There's probably little benefit in carrying both 32% and 36% - the difference in deco time is marginal. Your profile suggests you're a PADI AOW with 30 dives, in which case this dive may be beyond your current training/experience. keep safe vid

September 10th, 2007, 06:27 PM	#9 (permalink)
amascuba(Offline) New Member Join Date: May 2006 Location: West Texas Posts: 143	This is a scary profile. Have you been trained for deco diving? I wouldn't do the profile that you prescribed at all.