O2 better than 50% for single deco gas dives?

[JohnnyC]

Who in the hell dives 20/80? That’s a terrible idea.

 

[Wookie]

I like 50% or 70%, I never like 100%

 

[Centrals]

Who in the hell dives 20/80? That’s a terrible idea.

I don't think so!

Same result for 30/70.

Having two deco mixes is better than a single one.

 

[tomfcrist]

Having two deco mixes is better than a single one.

Define “better”.
Taking two deco gasses on a dive “just because” adds complexity that is not always needed.

 

[Centrals]

1. Get off quicker
2. If one of them fails for whatever reason, no need to rely on the back gas for deco entirely.
3. Donate/share the deco mix with your buddy if he/she has lost it.

You have to decide which is the preferred way, complexity or simplicity. Nothing is perfect.

 

[JohnnyC]

I don't think so!

Same result for 30/70.

Having two deco mixes is better than a single one.

Diving 20/80 is like diving VPM, a silly idea.

 

[kafkaland]

Who in the hell dives 20/80? That’s a terrible idea.

20/80 is over a range of depths/times a good approximation for ratio deco. I have used it when diving with GUE buddies to be on a similar schedule. But otherwise, no.

 

[rjack321]

20/80 is over a range of depths/times a good approximation for ratio deco. I have used it when diving with GUE buddies to be on a similar schedule. But otherwise, no.

In this example, meh no big deal
They stop way the hell too deep - still

 

[beester]

As already stated (in the first reply btw) whether you take 50% or 100% doesn't impact the profile that much in typical T1 dives (30' max deco max depth 51m)... what is important is indeed your gas and gas reserve planning. For a typical dive in this range (let's say 30' BT at 45m) you would get on your deco gas 10 to 15 min later in case of O² needing that amount of extra reserve for you and your buddy.

PS:Totally off topic, I'm not following the board that much anymore but, can anyone give a quick brief on why Devondiver was banned? The times I saw him comment, his posts seemed on the mark, and well composed.

 

[PfcAJ]

20/80 is over a range of depths/times a good approximation for ratio deco. I have used it when diving with GUE buddies to be on a similar schedule. But otherwise, no.

No.

No. No. No.

Algorithm first, ratio second.

The algorithm is the baseline and you figure out the ratio based on that. Picking a ratio and adjusting the algorithm to try and fit it is backwards and bad practice.