But then a single tank backmount, wow, that is not redundant, you cannot see it, most people cannot close valves, most people dive only with 1 valve, wow, this is than dangerous. So shall we make sidemount standard?
No, of course not. Every way of diving has it's own risks. With sidemount, people forget to look at 2 spg's, instead of one with backmount. (ok, cmas has 2 spg's on a twinset and some divers dive independent doubles). There are divesites where it is way more easier to get in the water with a backmount set than a sidemount set, and visa versa.
Mexico is a great place to dive sidemount as you don't have to worry about narrow passages. But the first time I went there, we used a Gue divecenter and then sidemount was not part of their curriculum. So we rented twinsets. There were some caves we could not do because of the twinset, but most are possible.
Remember, most cave divers stay on the 'recreational cavediving' level. So they are happy with following lines that are already there, they never do explorations. And a lot of cavedivers never go to narrow passages, so they maybe dive with sidemount equipment, but don't need it. And as a cave diver or technical diver, you must be able to reach your valves and know how your equipment works. This is not diferent from sidemount and backmount.
But have you tried boatdiving with sidemount? Especially when you have to put on the cylinders in the water with waves? All divers are waiting for that very slow sidemount diver. I have had this, they did not have enough twinsets for rent, so I said, then I will use sidemount as I was the only diver that was able to dive sidemount. So everybody was already ready and I was still putting cylinders on my harnass.
The same you see in mines, they are quite cold and are absolutely not that narrow that sidemount is needed. The sidemountdivers are the slowest ones and if others have to wait in the water, they are already cold before the dive starts (yes I agree, sometimes I take my sidemount ccr in old mines, but the last times I took my backmount ccr as this is way much faster).
When I prefer sidemount is for example in the caves in the Jura, you need to walk quite far and I can put 1 cylinder or my sidekick in a backpack and then bring it to the water.
But as soon as I start with equipment removal in a cave, so the cylinders clilpping of my harnass to pull them through narrow passages, the 'more safety' with sidemount is completely gone. As a diver you take more risks by doing such passages. You completely dive solo then. Sometimes you cannot move back, so if you want to get out, you need first go further till you can turn.
I also know from an accident where 2 divers died in the Netherlands in a wreck, 2 recreational dive instructors. They did not use a line. So backmount single tank divers, but their accident has nothing to do with the equipment.
I almost died myself when I was a recreational diver due to group pressure, on the same way these 2 people died. We did not take a line with us because others said it was not needed. I have decided to share air at the moment my buddy runned out of gas and happely we found the exit. After the required decostops, I had 15 bars left in my single 18 liter steel. And I decided to learn cave diving and start my technical career.
In Tulamben, on Bali a couple of years a German diver and instructor dissapeared, he had it's own divecenter there, and is never found back. He was a diver who dove very often to 90m on air because helium was already extremely expensive in Bali.
I know from a died person in the Christine mine in Germany because they runned a compressor in the entrance area and CO was the problem.
It sound now maybe that Germans always die because they make strange decisisions, but also that is not shown in overal statistics.
There are a lot of examples from other accidents where other nationalities made decisions that most would not make. In Ginnie it was I believe, divers died because they took of their rebreather. I would never take off my backmount ccr to go through passages, there are limits in my diving.
So to make safe dives, the first step is learn how your equipment works and stay confident, practise the skills needed for the dives you do or want to do.
Then the second step is follow the learned rules about safety.
Then third, if you don't like to do things, there is never a need to do it. There is not best diver in diving. You will never win a gold medal with diving on the olympics.
