Your story reminds me of one of my early dive experiences, with a very similar outcome.
My son and I were both "newbies" with less than 20 dives' experience. The only equipment we owned were masks, snorkels and fins... We were on vacation in Brazil, and decided to go dive on Fernando de Noronha for a few days. There are few dive ops on the island, and we chose the one that looked most serious (Atlantis Divers). They rented us BCs and regulators, and showed us where we could find wet suits. We should have started being suspicious when we realized that the only instrument attached to the regs was an SPG. No depth gauge. No compass. And of course no bottom timer or computer. I should have checked the competition at that time, but I somehow suspect that it would have been no different.
We went for three two-tank outings with them. We were in groups of half a dozen with a single DM. I remember one dive quite clearly. In his very abbreviated briefing, the DM told us that we would be diving to 35m. I remarked that my son and I were not qualified to go to that depth. He just scoffed and said we would be perfectly safe. We made the dive, much of which consisted in trying to keep up with the group while finning against a strong current. When we finally caught up, my air was down to about 30 bar. To his credit (such as it is...), the DM aborted the dive, and gave me his octopus until we surfaced.
While no actual incident occurred during the dive, a lot of things were wrong:
- we had no idea of how deep we were
- while I knew I was running low on air, making an ascent would have separated us from the group; moreover, I was not confident that I could have made a safe ascent from that depth without a depth gauge
- the DM has no idea that there was a problem because he could not see us for much of the dive
I could go on. Probably, diving on Fernando de Noronha using rental gear was foolish to begin with. In many countries, the dive op would have been called to order for not following basic safety procedures. I should have called off this dive, and maybe given up diving on the island altogether. But we had paid a lot of money to be there...
The experience taught me a few things, though. When we got back home, I bought proper gear for my son and myself. No matter where we go, we bring at least our own regs and computers. We enrolled in a rescue level class, and keep practicing skills and emergency procedures. And I would gladly go to Fernando de Noronha again, this time with the knowledge that we can handle most situations and aren't dependent on DMs anymore.
Victor J.