Scubapro Galileo 2?

[mnjhuz76]

Do you also sell the Perdix AI? How does your price on that (with transmitter) compare to those others?

Don't know his prices but at least here in Europe there's a significant difference between the Perdix AI (little short of 1,500 USD incl. transmitter) and a G2 (1,150 USD incl. transmitter w/o HR belt)...

Edit: And if you are an instructor, you can get the G2 in the above mentioned config over here for as little as 850 USD. Maybe SW provides a similar offer I'm actually not aware of.

 

[tridacna]

I have been in the SCUBA biz for over 40 years. I can sell and carry anything that I believe is the best. Period.

Obviously you believe SP is the best (and only). According to your website anyway. LOL.

 

[Hatul]

Well, I suppose that it's good that it has a feature to let you work around that annoyance.



Are you suggesting that you think the G2 is preferable to use for deco diving over a Perdix? Also, can you refer me to any recent, or somewhat recent, independent research that validates that their deep stops and/or variable ascent rate produces ascents that are statistically as safe or safer than ascents done without deep stops and done using a constant 30fpm/10mpm ascent rate? The actual research I've seen seems to suggest that deep stops are statistically more likely to result in incidents of DCS. And the algorithm used in the studies I saw, which produced the lower incidence of DCS, relies on a constant ascent rate (30fpm/10mpm). If there is other evidence out there that suggests deep stops and variable ascents rates are good things, I'd really like to read up on it.

The Perdix AI does not show GTR (Gas Time Remaining) at all once you do go into deco. That IS a minor annoyance when I have gone into deco and am planning to only have a few minutes worth of deco to do and do it on back gas. However, it's not a huge deal because I would not go into deco unless I knew I had so much gas for a safety margin that my GTR is really of no concern.

And, I am very hopeful that Shearwater will address that in a future firmware release. It's their first time out with air integration, so it shouldn't be too surprising that they have a rough edge or two. It definitely doesn't seem as egregious as having safety stop functionality for years and still making their users manually start a timer to count down safety stops.

I recall a statement from Shearwater re their GTR and was something to effect that they don't consider this an important feature of air integration, the main benefit, according to them, is to show the tank pressure in one display. So with that philosophy they may never show the GTR when you go into deco.

The issue of deep stops was once discussed and debated in an article in Dan's Alert Diver and it's controversial. The Galileo shows a deep stop (when this option is turned on) at a depth when you start offgassing, which is useful to know. It's hard to see how stopping at that point can make your profile less safe. They call it Profile Dependent Deep Stop and if you ignore it you don't get penalized.

I'm not sure why Scubapro chose to start the auto safety stop timer at 15 feet rather than 20, but it's mainly an issue in shore diving where the ascent from 20 to 15 ft is very slow.

 

[stuartv]

The issue of deep stops was once discussed and debated in an article in Dan's Alert Diver and it's controversial. The Galileo shows a deep stop (when this option is turned on) at a depth when you start offgassing, which is useful to know. It's hard to see how stopping at that point can make your profile less safe.

It will be easier to see if you watch this video:


In short, stopping at the "deep stop" means you are off-gassing in fast compartments, but you are still on-gassing in slow compartments at that depth. The net result is surfacing with more inert gas tissue loading in your slow compartments. That makes your profile less safe.

Don't just take my word for it. Watch the video.

 

[Hatul]

It will be easier to see if you watch this video:


In short, stopping at the "deep stop" means you are off-gassing in fast compartments, but you are still on-gassing in slow compartments at that depth. The net result is surfacing with more inert gas tissue loading in your slow compartments. That makes your profile less safe.

Don't just take my word for it. Watch the video.

Hi, Stuart
That's a very informative video on decompression. If you look at the video at 24:50 he points out that his deep stop discussion does not apply to the optional single deep stop on a no-stop dive. His discussion refers to the deep stop model of decompression which is a different kettle of fish, even though the word used deep stop is the same.
He points out that adding a deep stop on a no-stop dive is controversial with some finding it beneficial in preventing micro bubbles and some finding no benefit.
The Galileo deep stop is optional and if you miss it there is no penalty in the algorithm.
Also the Galileo algorithm allows setting a conservative factor (MB >0) which may add optional deco stops. These deco stops are shallow just like mandatory deco stops but you're not penalized if you blow them.

 

[CZS]

I'm not sure why Scubapro chose to start the auto safety stop timer at 15 feet rather than 20, but it's mainly an issue in shore diving where the ascent from 20 to 15 ft is very slow.

I wish Scubapro/Uwatec would make this configurable, since I too would prefer it kick on at 20ft. Maybe in a future FW update?

It will be easier to see if you watch this video:


In short, stopping at the "deep stop" means you are off-gassing in fast compartments, but you are still on-gassing in slow compartments at that depth. The net result is surfacing with more inert gas tissue loading in your slow compartments. That makes your profile less safe.

Don't just take my word for it. Watch the video.

One thing I want to point out is that Scubapro implements it's deep/PDI stops on no stop dives as well. While deep stops have been pretty well discredited in terms of decompression dives, there *may* be some benefit in terms of increasing repetitive dive time when observing the PDIS on recreational no stop dives. The thing to remember here is you're a) not penalized for ignoring a PDIS, and b) can easily turn it off completely in the settings of the G2. As mentioned in another post above, if nothing else it provides the diver a depth at which offgassing begins, which might be useful at times.

 

[CZS]

If you look at the video at 24:50 he points out that his deep stop discussion does not apply to the optional single deep stop on a no-stop dive. His discussion refers to the deep stop model of decompression which is a different kettle of fish, even though the word used deep stop is the same.
He points out that adding a deep stop on a no-stop dive is controversial with some finding it beneficial in preventing micro bubbles and some finding no benefit.
The Galileo deep stop is optional and if you miss it there is no penalty in the algorithm.
Also the Galileo algorithm allows setting a conservative factor (MB >0) which may add optional deco stops. These deco stops are shallow just like mandatory deco stops but you're not penalized if you blow them.

Not sure how I managed to miss this post before posting my previous reply, but +1 to all of this...

 

[dmaziuk]

He points out that adding a deep stop on a no-stop dive is controversial with some finding it beneficial in preventing micro bubbles and some finding no benefit.

Simon's more recently stated (e.g. in "nedu study" and "ratio deco" threads here on SB) that current belief is "overpressure" in fast tissue compartments is not as bad as previously thought. The goal of a deeper initial stop is to avoid that, the flip side is continuing on-gassing of slower tissues. It seems the flip side is worth than the disease.

I don't see why this thinking would not apply to SP's "deeper stop" just as much as to the more traditional "deep stop".

On a non-stop dive the fast tissue may not be as saturated to need a deeper stop in the first place, or it may be saturated enough to be subject to the above reasoning. Either way, I'm sure "PDIS" is a greate feature as long as it can be turned off.

 

[dazulrich]

2nd firmware update v1.2 on the SP G2 website. But as always no release notes or anything.

 

[Hatul]

Simon's more recently stated (e.g. in "nedu study" and "ratio deco" threads here on SB) that current belief is "overpressure" in fast tissue compartments is not as bad as previously thought. The goal of a deeper initial stop is to avoid that, the flip side is continuing on-gassing of slower tissues. It seems the flip side is worth than the disease.

I don't see why this thinking would not apply to SP's "deeper stop" just as much as to the more traditional "deep stop".

On a non-stop dive the fast tissue may not be as saturated to need a deeper stop in the first place, or it may be saturated enough to be subject to the above reasoning. Either way, I'm sure "PDIS" is a greate feature as long as it can be turned off.

I'm no expert on decompression, but I'll give it a stab. If we make a short deep stop on a no-stop dive the controlling tissue is offgassing while a slow tissue may be ongassing. The controlling tissue was closest to saturation by definition, and is the one that is most likely to form microbubles, so offgassing this tissue before proceeding may help prevent microbubbles. Unlike the deep stops of the deco dive that the video is referring to, in this case the slow tissue never become supersaturated, so the continuing ongassing of a slow tissue may not be an important factor in this no-stop dive. It's just a thought.