Our worst was not equipment related to the charter, but rather how they ( and , in fairness, us ) operated during my OW cert dives in Cambodia. Dives 1-4. I guess all of us in my family learned things not to do. First 3 dives were great, actually the 4th was great also 'till we surfaced. 5 hrs offshore, my wife and youngest son had been told by the captain about the good snorkeling around a small island. They decided to go. This was during my ( and my oldest son's ) last cert dive. Just before we left the boat, we were told the boat had another diver that wanted to do a deep dive. They told us to do our shallow cert dive as well as the snorkel and they'd be back to get us, they'd be about 1 mile away. Duh ! OK ! They also told my wife and son that, if either of them got tired, just swim to the island and the boat would pick them up .
What actually happened was, my wife and son started snorkeling, and the 5 of us doing our certs descended about 10 minutes later in the same area. Upon surfacing after the dive, ( 'bout an hour later ) we see my wife and son totally exhausted on the surface with my wife starting to enter the panic mode. They had been in the water 'bout 70 minutes by then. I will add that my wife and son are both good, confident snorkelers, having done it many times in the past in various areas. Turns out, they had tried to get to the shore twice in different areas and couldn't due to the pounding surf and coral reef. My wife said they would have been torn to pieces.
After we surfaced, my wife hung onto me for a couple of minutes and then, the DM on our cert dives took off his vest, blew it up fully and let my wife and son hang on to it for the 25-30 minutes it took the boat to come back to get us. She also spent some time hanging onto the anchor line from a fishing boat that was nearby. She was livid to say the least. Total time from when the boat left to its return was at least 1 hr 30 to 1 hr 40 minutes, with the snorkelers in the water 10 minutes before departure.
What we learned was the obvoius. Mistake #1 ( ours ) If the boat is leaving ( which all of us knew ) don't get off the boat. We were fine in the scuba gear, but the snorkelers were not, to say the least. Mistake #2 ( not ours ) the captain and crew should have known about the coral and the extremely limited access to the island. Mistake #3 ( not ours ) Don't send out snorkelers, leave and come back in as much as 1 hr 40 minutes later. Not good. Mistake #4 ( ours ) We assumed they knew what they were doing.
In summary, our family learned. Main lesson is, if the boat is leaving and you are snorkeling, don't get off, no matter what they say. We had floatation gear with the scuba, we were fine, the snorkelers were not so equipped.