Reefraff (and actually anyone else that wants to comment), this is not a flame as i know jack about such things, but what should have happened then?
Fair question and no offense taken. It's hard to
know what should have happened because there are many details that we don't have. As a general rule, however, I would consider the situation as described to be a real emergency: we're looking at an inexperienced diver getting blown away in moderate seas where there is a lot of other traffic - there are 8 mooring balls on the SG, as I recall, and they're busy.
The two big concerns are that the diver will panic or that she will get run over - she's not going to get lost in these kinds of seas. An experienced diver isn't likely to panic and will (hopefully) have the equipment and presence of mind to make her presence well known and certainly should be able to establish positive bouyancy and float safely on the surface until somebody can come and retrieve her. With an experienced diver, this is more of a "Free beer for everybody" nuisance than a battle stations emergency, but that's not the what was going on.
Last choice should be to move the boat. That requires getting the divers out of the water (or worse, sending them to the bottom where they're out of the way) and that takes a lot of time. A fast response is almost always better, so getting a line to the diver is the bestest solution. The decision to swim the line to her makes sense, given her inability to land on top of it when it was beneath her feet and the vagaries of wind and current. Fortunately, there were two DMs available, one to stay and attend to the divers in the water and the other to effect the rescue. I don't think it much matters which one did what, but I like the idea of the tasks being distributed like they were - the divers in the water are familiar with the DM that's with them and the DM on the boat has the edge on being able to see exactly where the lost diver is until he hits the water. Especially if the DM on the boat was not yet geared up, he's the one that should have made the rescue since he wouldn't be encumbered by gear.
As UP pointed out, one of the things we don't know is whether or not there was a long dragline already out. If there wasn't, the DM's should both be taken out back and whomped on. A heap of trouble might have been avoided.
Sending the divers to the bottom as a way of clearing the props is effective but presumes that they are safe and will remain so until the boat can effect a rescue and return to the ball. Again, given the inexperienced nature of at least some of the divers on the boat and the conditions, this would seem to be a stretch. As it turns out, this wasn't just a top current that they were fighting and conditions on the bottom forced an early turn of the dive, a worst case scenario for this group. What would have happened if all these divers tried to return to the surface, only to find the boat gone? Oops. Would they have had the skill and presence of mind to hang onto the mooring bouy anchor line in 30 feet of water until the boat returned and safely hooked in? Scary assumption, given that the dive was turned because the current was too ferocious.
I've only been on the SG once so I can't say what conditions are normally like, but we had a pretty stiff breeze. The current was at least a couple of knots on the surface and not much better on the bottom, strong enough that if you let go of the line you were going sailing and everyone was careful to keep to the lee while on the bottom. Someone commented that it was the kind of current that makes everyone look good - fluttering in the current as you clutch the line means you can't help but have a nice prone position and nobody looks like the typical recreational divewalker.
I'm sure if you think about it, you know the answer to the question you asked about whether the other divers should wait it out while a recovery is effected. Of course you should. Lots of things are different in a slight current, even if the diver is having a hard time swimming back to the line. It isn't a light current if the lost diver is 200 yards gone in the time it takes to react and everyone should have stayed on the boat so that the option of moving the boat quickly could be preserved. This is why it's an advanced dive and why newbies should avoid it. Somewhere along the line it's become popular to think that the only difference between a new diver and an advanced diver is the gullibility to part with a few dollars for another stupid class, but nothing could be further from the truth. Advanced OW divers have more experience and have spent another 5? dives working with an instructor, learning new things and honing old skills. It may not be much, it may not be enough, but it does make a difference.
Lots of stuff we don't know about this incident, so much of this is just guesswork on my part. That said, the big lesson from this dive would be to remember to dive within the limits of your training and experience and to avoid trust me dives at all costs. When someone says, "Advanced Open Water required," the assumption should be that they mean it. Safety in diving should be a cold, hard thing and requires all of us be willing to sacrifice the dive on a moments notice.
