I have several... none of which there's an appropriate category for in the poll, so I didn't respond to the poll.
The one that was potentially most catastrophic (SeaJay's opinion of the incident not withstanding) was when a group of twelve of us were abandoned by a native boat captain roughly two miles offshore. To this day I really have no advice as to how one could prevent such an incident.
The second incident involved my instructor trainer, an untrained native diver, me and a second instructor candidate. We were doing a deep dive in which we intended to exceed the 130 fsw recreational limit on a 5000 fsw wall when the IT became seriously narced and decided to see if he could reach the bottom. At around 120 fsw or so the IT took off for the bottom in a vertical swimming decent without warning. The alarming thing to me has always been how long it took the other candidate and I to arrive at the conclusion there was a problem (even though we both agreed afterwards that we hadn't thought we were narced at the time). Swimming hard we didn't catch up to the IT until 200 fsw feet and he actually tried to fight us off as we attempted to "change his mind" about his intentions. This created two additional problems... (1) we were exerting ourselves hard for an extended period in 200' of water -- CO2 buildup was an issue and I was in serious breathing trouble by the time we got things settled down which was, in turn, sucking serious air supply from my tank not to mention making nitrogen narcosis and oxygen toxicity growing issues, and, (2) his aggression was real -- we both lost our regulators at least once struggling with him and I had my mask flooded without warning -- which when already in breathing trouble was a dead serious issue. By the time we "solved" the problem with the IT we were at 218 fsw (my deepest dive ever) and I was technically a rescue candidate myself though I rescued myself thanks to good training. By all rights, this dive should have been a disaster and we were pure and simple lucky. One more link in the accident chain almost certainly would have resulted in at least one fatality.
Lesson learned -- don't push your luck. If we wanted to do a deep dive like that, we should have chosen a location with a hard bottom. Having never been so deep before it was the height of stupidity to have tried in a location where the bottom was known to be fatal knowing full well we had no idea how we would react to the depth. Second lesson learned... in choosing to make the rescue, I made several bad choices of my own which by all rights should have killed me, too. I do not regret that we made the rescue effort and am, obviously, pleased at the outcome -- but the realization of what the outcome should have been is not something to be taken lightly. When teaching first aid and rescue, we always teach that you should not endanger your own life to rescue another... we both violated that rule and very nearly turned one accident into three. I sincerely believe that the only reason either of us survived the rescue itself was because the attempt required the very narrow mental focus that is about the only thing that is possible to do when you're narced -- mind you that not once during the rescue did I ever actually think to see if I had air left in my tank (though I was worried about depth -- why?)
The third incident was in 1991 and one that was the direct result of sheer stupidity on my part and but for the grace of God, should have been fatal. I was working as the DM on a 60 foot live-aboard from which we were diving an area in the Caribbean where there never had been moorings. At that time, the policy was to use a "wreck hook" on the base of a coral head where it would do the absolute least damage to the reef. For those who do not know what a wreck hook is, it looks like a giant treble hook a fisherman would use... three pointed hooks about two feet long and eight inches with each set one third of the way around a circle. The boat would pull up to the dive site and, as the DM, I would enter the water with the wreck hook and swim down to the reef to select a place to set the hook and then physically position the hook to hold the boat at the site. Once set, I would pull on the line to signal the tender the hook was set and the captain would allow the slack to be taken up. While this is happening, I'm supposed to sit back away from the hook and observe to be sure it's going to hold. There's the rub... I had been working the boat all winter and had never lost a set, so I got cocky and would often begin my ascent early to reduce the bottom time I was getting on the set and to get the divers into the water sooner.
In this particular case, the seas were a little rough -- about 4 feet or so -- and the boat was bouncing pretty well no the surface. As a result, I was in more of a hurry than usual so I could get the divers into the water before they got too hammered on the dive deck. I set the hook, gave the tender a few pulls and waited to see the slack pull up. As soon as the anchor line went taught, I started up the line on my ascent. As I went up over the position I had set the hook in I was looking down at the hook to make sure it was secure and as I progressed by angle of view moved closer and closer to my chest. At almost the exact instant my chin hit my chest the boat heaved on a large swell and the force broke the coral head. The wreck hook shot out of the coral like it had been fired out of a cannon. The first impact hit me top dead center in the breast bone -- actually about one inch south of it. What saved my life was that I had a fairly large console mounted dive computer and I kept it clipped off on the front right clip of my BCD. As luck would have it, the hook hit the face of my computer instead of the soft flesh under my rib cage. As it were, the hook penetrated the face of the computer and ripped the LCD out of it.
Keep in mind that I was looking directly at the hook when it broke out of the coral head while traveling directly up the anchor line. This means that the line of travel for the hook was more or less parallel to my own line of travel while I was bent at the neck and waist at an oblique angle... Once the hook had ricocheted off the front of my computer, the second point of impact was more or less straight on to and dead center in my mask as I looked back at the hook. The impact was strong enough to snap my head back but for whatever reason the glass in the mask held and did not shatter. Maybe I was already subconsciously reacting to it and was already moving my head back, I don't know because it all happened way to quickly for me to do anything other than note the key events -- I seriously had no time to even think about any of it until it was all over. Had the mask not held, I'm sure I would have been dangling with the hook in my head like a marlin when they pulled me back onto the boat.
Lesson(s) learned -- no matter how good you think you are, you aren't. Safety is safety and the instant you begin to take shortcuts, you are at risk of an accident. Also, big boats exert a degree of force you can not imagine... anchor lines are subjected to incredible tensions in rough waters. As a rule there's going to be enough slack in the line to handle it... but sometimes things go wrong. The anchor is not a place to play around, especially on a larger boat.
