Info Scubapro Announces the availability of SP's newest high end technical dive computer with full GF support, G2 Tek, in the EMEA market

[Wibble]

Why would you want to go back diving within 24 hours of your missing a deco stop in a prior dive?

Depends what you mean by "miss a stop".

• Come up at SurfGF 95 — chances are you’re fine.
• Miss your 24m/80ft stop to get to your 50% gas switch and extend that stop— chances are you’re fine
• Have a buoyancy fart and drift above the ceiling then drop back — chances are you’re fine
• Realise you’ve the wrong gas selected, air not nitrox, so shortened your decompression— chances are you’re fine
• Running the computer as a backup but running the deco on another computer which might be running different algorithms or GF's — chances are you’re fine
• Running the computer as a CCR standalone backup for bailout

There’s many times when you know more than the dumb computer.

It’s arse covering by SP who’ve sold you a brick masquerading as a "technical" dive computer.

 

[BoltSnap]

@Wibble @davehicks @happy-diver @stuartv @rongoodman @scubadada @hedonist222 @tursiops @Brian G @Degenerate @brsnow @Sevenrider860 @Rayk @lexvil et al.

Please give me more feedback on you concerns about the G2 Tek and I'll be VERY happy to deliver to the responsible party at SP HQ in EU. I have direct contact with them. They do listen to feedback as long as it is reasonable and constructive. It will be best to write it in "outline/bullet" format without being an essay type.

I'd really appreciate your feedback. I am writing something myself but your feedback especially the technical diving part will be most welcome. You can send them as PM to me too.


NOTE: I don't work for SP or gain anything from doing this at all except hoping to contribute to develop a better computer that would be closer to the ideal dive computer for technical and recreational market. In this case technical market. I will acknowledge to SP that the work was collaboration with friends.

 

[tursiops]

@Wibble @davehicks @happy-diver @stuartv @rongoodman @scubadada @hedonist222 @tursiops @Brian G @Degenerate @brsnow @Sevenrider860 @Rayk @lexvil et al.

Please give me more feedback on you concerns about the G2 Tek and I'll be VERY happy to deliver to the responsible party at SP HQ in EU. I have direct contact with them. They do listen to feedback as long as it is reasonable and constructive. It will be best to write it in "outline/bullet" format without being an essay type.

I'd really appreciate your feedback. I am writing something myself but your feedback especially the technical diving part will be most welcome. You can send them as PM to me too.


NOTE: I don't work for SP or gain anything from doing this at all except hoping to contribute to develop a better computer that would be closer to the ideal dive computer for technical and recreational market. In this case technical market. I will acknowledge to SP that the work was collaboration with friends.

At the very least, allow that SOS "feature" to be turned off. It is not a bad idea for most rec divers; it is a terrible idea for most tec divers.

 

[Brian G]

tl;dr at bottom

Hopefully there is someone who can map this out for in a bit more detail. As I understand the manual, the G2 Tek will only "lock you out for 24 hours 'cause it's a dumb computer" if you are at the surface for more than 3 minutes after having missed a mandatory deco stop, after having automatically raised your GF to 100/100. If you were diving a Perdix in any or all of the above scenarios, what would the computer indicate?

If you're using it as a backup (but not using it as your deco computer, not sure how it's a backup then) and your primary dies, so now your only computer does not have your correct gas history. Will a Perdix eventually clear you for the next dive? Sort of like how if you violate your NDL on many rec computers, but ascend slowly, the violation will clear?

I can definitely see a couple of scenarios where this would be useful (and I'm sure there are others). Say you had to short a stop by 30 seconds for some very important reason. It would sure be nice for your computer to just take that in stride. Or if for some (also very important) reason you decided that you needed in-water re-compression (frowned on by almost everyone, but might be the least-bad option in some circumstances), it would be cool if your computer would just keep on keepin' on.

You don't have to convince me that the Perdix is better. If I decide to get into tech diving I'll sell my dumb computers and get the latest greatest Shearwater wonder. But I would like to know more detail on exactly why.

tl;dr I guess my only question is - Will the Perdix give you useful dive functionality if you surface after having missed a mandatory deco stop. Will you be able to safely dive, using that computer as a dive computer, and with it knowing your correct tissue loading, within 24 hours?

Thank you very much for your time,
Brian

 

[tursiops]

.

 

[rongoodman]

What makes you think the Shearwaters wouldn’t know your “correct tissue loading”? Your tissue loading is why it’s complaining and there’s no reason to think that the model will quit working just because the leading compartment has a GF greater than 100.

 

[jborg]

there’s no reason to think that the model will quit working just because you’ve overloaded the leading compartment

Isn't there every reason to think precisely that? What testing has there been of Buhlman ZH-L16 or other algorithms under the circumstances where the M-value oversaturation is significantly exceeded, yet the diver continues diving under the assumption the model holds?

It seems reasonable to me that the computer would do its best to guide the diver to the surface (what other options would it have?), but then say "model parameters exceeded, it's not known to be safe to continue diving under current circumstances".

(If this "SOS mode" somehow kicks in underwater that's a different discussion. I'm assuming it kicks in at the surface, after violating stops.)

 

[Wibble]

Sticking neck out here...

As I understand it, Gradient Factors bring down the maximum tissue pressure in compared with 'raw' Buhlmann. One could dive at 100/100 and should be fine, but we tend to change this to add in additional conservatism, e.g. 50/80. This adds more conservatism at the bottom than on the top.

Thus exceeding a stop by 1m/3ft should still mean you're within the 100/100 limits.

BTW stops tend to be 3m/10ft and each metre is roughly cleared as a third of the stop time. Example 6 mins at 9 metres will be a ceiling moving up by 1m per two minutes.

All the mathematics needs to be proven; I don't have the tools to simulate this; but I do believe it will be the case that you'll be under the 100/100 (m-value?) limit.

Locking out within this depth is pointless and especially so if you're running your deco from another computer with this as a backup.

Did ScubaPro catch this lockout disease from Suunto?

Thankfully Shearwater didn't listen.


If I'm wrong in this understanding, I apologise and will learn.

 

[rongoodman]

You could always try forcing one into a deco violation by specifying a hypoxic mix and then watch the tissue graph to see how the various compartments unload after surfacing.

 

[jborg]

Thus exceeding a stop by 1m/3ft should still mean you're within the 100/100 limits.

All the mathematics needs to be proven; I don't have the tools to simulate this; but I do believe it will be the case that you'll be under the 100/100 (m-value?) limit.

It was mentioned in the Luna thread (I think) that the computer will increase GF up to 100/100 and recompute when stops are missed, so I think the lockout would occur when missing stops at 100/100.