Apeks Quantum...too Conservative?

[scubadog]

Used the Quantum for the first time yesterday, as did my buddy. We had a drift dive planned over a reef with a max depth around 32 metres.
We planned to stay at around 24 - 25 metres. The Quantum gave us an a no deco time of 25 minutes at 24 metres, BSAC 88 tables 30 minutes at 24 metres.
Into the dive...4 minutes after leaving the surface we are at 25 metres, 6 minutes later we are 26 metres. Another 6 minutes and we are still at 26 metres. Another two club members had stayed a few metres below us most of the dive, 18 minutes into the dive, they signal that they have found something...we descend down to 31 metres, I´m now being told I have 3 minutes left before I go into Deco, I signal to my buddy that we need to go up and level off...2 minutes later we´re back at 24 metres.
Now we are at 24 metres 24 minutes into the dive and I have 2 minutes deco on the computer. I launch the DSMB, and we take 5 minutes to reach our stop at 6 metres. We do 3 minutes, and a slow ascent to 3 metres, a further stop of one minute and then a slow ascent to the surface.

Now I felt fine during the dive, until Kirsty [ buddy ] started telling me about what she had seen, I realised I hadn´t anything. In all honesty I hadn´t, I had been spent most of my time looking at the computer, and checking my SPG.
Before this dive we had only used bottom timers and tables, and I always felt quite confident with what we had planned.
I always thought that the BSAC 88 tables were a little conservative, the Quantum seems to be even more conservative...Or is just me ?
We discussed the dive with our friends, the ones who were below us for most of the dive...one of them has a Suunto 'S' the other a Stinger. They said at no point during the dive did they show any deco time.
I may have been having a bad, although I felt fine...I know I was using a new piece of equipment for the first time, and that 'Deco' is not something that I´m use to.
Any comment will be much appreciated...

Pete.

[gobfish1]

Originally Posted by scubadog

Used the Quantum for the first time yesterday, as did my buddy. We had a drift dive planned over a reef with a max depth around 32 metres.
We planned to stay at around 24 - 25 metres. The Quantum gave us an a no deco time of 25 minutes at 24 metres, BSAC 88 tables 30 minutes at 24 metres.
Into the dive...4 minutes after leaving the surface we are at 25 metres, 6 minutes later we are 26 metres. Another 6 minutes and we are still at 26 metres. Another two club members had stayed a few metres below us most of the dive, 18 minutes into the dive, they signal that they have found something...we descend down to 31 metres, I´m now being told I have 3 minutes left before I go into Deco, I signal to my buddy that we need to go up and level off...2 minutes later we´re back at 24 metres.

your point is ?,

[jptaylor9]

[scubadog]

Sorry, I pressed submit by mistake before I had finished.

[nigelH]

Originally Posted by scubadog

The Quantum gave us an a no deco time of 25 minutes at 24 metres, BSAC 88 tables 30 minutes at 24 metres.

Welcome to the real world.
Nothing is as wild as BSAC88's idea of a first dive.
It gets worse if you go deeper: if you suggest that you can do 14 mins at 51 meters then deco for 2 mins at 6m on air to any other deco system in the world and it will wisk you off to the pot. Proplanner, for example, on 0% conservatism suggests 1@9m, 4@6m and 8@3m

Go with the computer. It has your best interests at heart.

nigelH

[Richie]

I have used a Quantum now for 19 dives. The first few were back to back with an Aladin Pro Ultra. The quantum has always a bit more conservative except for no fly times.
If it enhances safety then a few minutes watching the plankton go by is a small price to pay.

[Woz]

IIRC BSAC 88's times are back up to the the 6m ascent check depth, not bottom time. So you have to factor the ascent in too.

[Andrew H]

Originally Posted by scubadog

The Quantum gave us an a no deco time of 25 minutes at 24 metres, BSAC 88 tables 30 minutes at 24 metres.

I always thought that the BSAC 88 tables were a little conservative, the Quantum seems to be even more conservative...Or is just me ?

PADI would allow 25m at 25 min. I wouldn't call BSAC88 conservative at all. if you use Vplanner you get 4 min deco at 6m after 25min at 25m. Computers are usually far more conservative on square profile dives, but deco often clears on a slow ascent. Multi level dives really show the advantages of computers over tables, calculating deco on the fly.

Andrew

[dry suit diver]

Originally Posted by Andrew H

PADI would allow 25m at 25 min. I wouldn't call BSAC88 conservative at all. if you use Vplanner you get 4 min deco at 6m after 25min at 25m. Computers are usually far more conservative on square profile dives, but deco often clears on a slow ascent. Multi level dives really show the advantages of computers over tables, calculating deco on the fly.

Andrew

PADI table also says if within 3 groups of NDL stop at 3metres for 5minutes
25 minutes at 25 metres is within 3 of the NDL so stop must be made
sensibly though always good practice to do safety stop even if not required