We have all read it and the conclusions were beaten to death on various forums over a number of years. Simon and David did an amazing job of getting people to understand those results and the likely reasons.
Agreed. What stood out to me more than anything was the way they graphed the slow tissue loading. Less of an issue for me as an NDL recreational diver. My takeaway was that deep stops as shown in the study were a bad practice. I don't do, or plan to do, decompression diving so it's really not applicable to me at this point in my dive universe.
GF was invented to ADD (the then fashionable) deep stops to regular dissolved gas models (eg actual ZHL16). Suunto and other manufacturers added (usually optional) “deep stops“ which are actually just 1 minute halts in an ascent. I have a Suunto HelO2 which I use as a backup to a Perdix if doing OC dives. On something like a 35m dive with a bit of deco or not it will give me a 1 minute top at 10 to 20m. If I ignore that it wants a 4 minute safety stop instead of a 3. For the same profile the Perdix on my other wrist will give me more or less the same actual stops. For a proper deco dive it will likely give me a 9m stop when the Suunto might give me a ceiling at 7 or 8m. The last stop might be a handful of minutes different, depending on the actual GF numbers selected and the P value the Suunto is set to. By way of illustration, three divers doing an 80 minute runtime on a 44m wreck using petrel/HelO2, HelO2/HelO2 and Petrel/abacus all had final clearing times within five minutes.
Interesting data. Thank you for sharing some real world experiences.
Why do I care? Well I don‘t care what you dive but actual buddies of mine come on here and end up spending £1000 or £800 on a Teric or Perdix AI and then only have one computer because otherwise their wives will literally murder them When they discover £2k spent on computers. This means we get constrained to computer/abacus plans or I lend them a spare Suunto.
Regrettably, Scuba, Private Aircraft, and Boats are all not hobbies for the poor man. It probably would be cheaper to light currency on fire and throw it in the air for entertainment.
For the vast majority of us these hobbies incur some form of compromise. So we have to make tradeoffs.
Everyone's choice, influenced by their diving goals and their budget constraints plus any oversight from the Admiralty (wives/partners/family) are right for them under the data that they had at the time. Some folks may need to dive with older computers, sealed computrers, or computers where the customer service is from Comcast.
I've admired Shearwater since they first came out. I really like the concept that I can do most of the maintenance myself. So if the computer turns on in my luggage somehow and drains the battery while traveling I can cure that in whatever place I happen to be in. If my rechargeable batteries suddenly decide not to recharge I'm confident I can buy a AA battery in the Maldives, Philippines, Hawaii, Egypt, Alaska, Australia or wherever I happen to be. All of which assumes I can afford to go to any of those places. lol. Most of my diving has been in the Caribbean which is easy and affordable to get to from Houston, Texas.
Net net is that the unpublished model was not the major factor when I decided to return the Suunto. It was one of several factors. I disagree with not publishing their model. Their hardware is unique enough that the model shouldn't be the competitive factor.
I also did not like certain things about the interface. I disliked how the bungie option attached to the computer and didn't realize how it worked until I got it and read the manual. I don't fully trust the strap. To put it another way I would not use that strap to secure a $1,000 USD bill. If it comes loose it will do so at an inopportune time where the computer will never be seen again.
I did like how the cable attached. That was genius compared to the IRda crap that my old SmartCom has. Well, at least until you lose the cable. No worse than magnetic charging though. If you lose or damage the Qi charger you are stuck until you find another one. Not sure how easy that would be in some parts of the World.
Customer service was a factor, and my friend that owns an LDS and who was my first Instructor not liking them was also a factor. Had I been stuck with it I could have survived, but I had the option to return it so I did. I had originally hoped the screen would be big enough to read without glasses. When I received it I realized that wasn't the case and I was going to be getting bi-focal inserts for my dive mask anyway.
As for backup computers..... for me it's really about not losing dives again. Trips are expensive. I got burned by my SmartCom adjusting the gas settings... My fault for not checking it, but it never occurred to me that the computer would brush against something and magically modify the O2 setting all by itself. That is a crap interface and no critical setting should happen by itself without confirmation. The little contacts were always difficult to use.
