Just because someone chooses a liberal computer doesn’t mean they have to always take it to the max.
It’s nice to know where the max is so that I have the choice to go there or not.
I recently recalled a dive that I did with a buddy years ago when we went to Farnsworth Bank. That’s a series of deep pinnacles along a ridgeline about 5 miles offshore from the backside of Catalina Island in Southern California.
The tops of the pinnacle start at about 70’ and the sides cascade down very rapidly beyond divable depths. 100’ vis, big purple hyrocoral, just a stunning place!
First dive of the day, I was using a Suunto and my buddy was a DIR guy at the time and was using a BT and doing the GUE thing of computing on the fly. Most of our dive averaged about 100’. It was a fairly square profile. It wasn’t really discussed before the dive, but I think he was figuring he had 20-25 mins at that depth. I’m also not sure if I made it clear that I had my computer was in compute mode and not in gauge mode. So after reaching depth and cruising around for a while my BT time was up. I had to tap him repeatedly letting him know my computer did not like was was going on. He ended up having to follow me and my computer up knowing that unless I didn’t want to end up in mandatory Suunto deco we had to start up otherwise I’d be benched and he would be out of a buddy for the rest of the day. He wanted to do a slow integrated ascent and the whole time my Suunto absolutely did not like that. I was riding it right to the last minute of NDL from initially running it out of NDL at the bottom. Every few feet of ascent it would only give me a minute or two. It wanted me to keep going without stopping. I had to keep tapping him pointing to my computer that the BT was running on fumes.
He wanted to stop at 50’ for a minute, then 30’ for a minute, then 20’, then 10-15’ for three minutes. I followed him at this point because I knew this was his GUE thing and I didn’t want to leave him buddyless on an offshore dive like that. Well this put me into deco.
After he was satisfied with his profile he cleared himself, my Suunto kept me at 15’ for something like 12 or 15 minutes which I had to do otherwise I would have been locked out. Good thing I had a big tank and plenty of gas.
So long story short, Suunto’s get very pissed off if you don’t get your ass up to 15’ when they tell you. Big penalties in the brig if you dilly dally.
I’ve heard this model called the “bend and treat” approach, which is why the GUE guys at the time where so opposed to anything that was against deep stops. Most computers at that time didn’t allow for deep stops.
Man ... I had exactly the same experience with my UTD dive buddies. I used to dive with a Suunto Gecko - Zoop and my UTD buddies would do ratio deco with the same staggered ascent you described above. My RGBM driven Suunto computer would get furious while I attempted to follow their profiles. My UTD dive buddies would always have more bottom time and it made me think that if the entire purpose of spending money on a dive computer is to give me more bottom time then why is my Suunto failing to deliver that? Isnt that why we buy a computer in the first place? It makes no sense why you would have a 430.00 USD Suunto Zoop which is giving you less bottom time then some guy doing ratio deco on an 89.00 USD bottom timer and repeatedly getting away with it! I did not understand decompression algorithms back then nor did I understand ratio-deco so I asked on scubaboard. You can look at those ratio deco threads that I started a while back and you will notice that those replies were given at time when
"ALL DIVE COMPUTERS WERE RIGHT." In other words, it doesn't matter whether the computer is running Buhlmann, VPM, RGBM, DSAT etc. as long as it is a computer it has got to be right!!!
As we revisit those threads in the light of what we are beginning to understand about decompression today, it turns out computer users that were running VPM and RGBM were basically on the wrong side of history. Buhlmann profiles with very low GF-los that intended to mimic deep stops were also on the wrong side of history but not as wrong as the VPM and RGBM. Since UTD was also attempting to follow these bubble models at the initial part of their ascent strategy, UTD was also in the same risk basket as these other computer users using RGBM and VPM.
Since UTD was a computerless crowd, they updated their e-learning, never had to reprint any books and the entire agency switched from deep stops to "relatively" shallower stops without any of their certified divers having to purchase a new computer. Technical divers who were on high end computers like Shearwaters etc were also able to incorporate shallower stops by increasing their GF-los while reducing their GF highs on their computers. The only crowd that remains stuck in the past is the recreational diver who was sold a dive computer. Since RGBM was the preferred algorithm in most recreational computers and three major manufacturers (Suunto, Mares and Cressi) used this as their default algorithm, chances are that in another five years time, if you will ever come across RGBM it will be in the hands of recreational divers diving in computers. Unlike UTD or other DIR divers, your average recreational diver does not have the training to plan a dive without a computer and modify his ascent to reflect whatever
HE believes to be modern decompression thinking. Unlike the technical divers who own high end computers, his entry level computer does not give him the option to modify gradients factors to reflect modern decompression thinking. He will be the only one left at the mercy of the RGBM. The good news for him is that at recreational depths RGBM generates stops not different from dissolved gas models so he will not encounter "deep stops" for which RGBM and VPM take criticism for. In other words, he is not in any danger as per say. The bad news for him is that on repeated dives, RGBM will shorten dive times and become really really annoying. If the only advantage of a dive computer ever was to give you more bottom time, then RGBM will lose that advantage rather rapidly in repeated diving.
In the end you have to ask whether you prefer gadgets over education or education over gadgets? Ideally, I would like to have them both but since they both require investment, the order in which I would like to have them is education first, followed by gadgets. Unfortunately we are in an industry where educator (instructor) is not making any money and the sales person (retailer) is the one who makes money. This means that gadgets will be sold first and the education you will get is how to run the gadget.
