Ok, so we've had about 40 responses now. I'm going to invite some of the more experienced members following along to go ahead discuss pros and cons of some of the answers given so far.
Having been summoned, I feel an enormous pressure to say something intelligent for a change.
I think Bob (NW Grateful Diver) and John (Cave Diver) have already stepped in with some good thoughts on the point by point questions. I also believe that, for the people who really are new divers in this forum, most of the answers have been excellent and on target. I would just like to respond to one specifically and then talk generically.
The only time I dove non-tropical conditions with low viz was during my O/W training at Chatfield Res. .
Jewls, I got rid of your turquoise font because it was giving me a headache.
What you describe is all too familiar to me, and it is why I hope I never have to instruct at Chatfield Reservoir again. What you experienced was a very unusual situation caused in large part because of the shallowness of water (21 feet max), which forced them to lay the line right on the bottom. Consequently, when instructors take students along that line, it takes tremendous buoyancy control, a skill far beyond that of OW students, to stay on it without rorotilling the silty bottom. The result is the worst visibility I have ever seen anywhere. The primary thing to do in that situation is not to dive in those conditions until you have a lot more--seriously a lot more--experience and training. You and your buddy should end the dive before you get separated, because you have to recognize that separation is almost inevitable, so you might as well get it over with right away. (I realize you did not have a choice in that class. When I did classes there I ran a line at about 15 feet. Our students didn't see the commode, but they stayed with each other.)
Speaking generically, buddy separation can be a very serious problem, and as most of you noted, the "look for 1 minute and then surface" rule will cover most situations. The key aspect of it is that
both buddies (or more in a larger group) must follow the plan.
Let me describe to you what happens when that doesn't happen.
I was with a group of 5 experienced divers diving in a fairly shallow reservoir (Aurora Reservoir, Jewls). It was just a fun dive. There is sunken Cessna out quite a ways from shore. The plan was that one of us would take a compass heading on the float attached to the plane and take the lead on that heading. The rest of us would follow in two wing-on-wing buddy teams. The visibility was relatively poor--maybe 8 feet. I don't know exactly how it happened, but when we were probably not far from the plane, the leader disappeared.
The remaining four of us turned toward each other at first to make sure we were all aware of the problem, and then we followed protocol. We looked around for a minute and began an ascent. (We had actually been very close the whole time. He later told us that while he was looking for us, he could hear us breathing but could not find us.) We waited on the surface in somewhat windy conditions, but he did not appear. We saw something curious in the distance--an inflated surface marker buoy drifting away in the wind.
Other than the visibility, this was an extremely easy dive--35 feet of depth in a relatively calm lake. He was an extremely experienced and knowledgeable diver. The odds of him being in trouble were very slim. We spent some time searching the surface, looking for bubbles, but there was enough wind to make that hard. We started getting nervous and headed for shore. We encountered him there. He had gone in under water.
When he had finally realized he could not locate us, despite being very familiar with the 1 minute search protocol, he decided on a new plan for getting back together with us. He inflated a surface marker buoy at depth and sent it to the surface so that we would spot it when we surfaced and go down the line to find him. Unfortunately, it had somehow come untied, which is why we had seen it drifting away in the wind. Realizing we could no longer find him by that means, he had reversed his compass heading and gone on back to shore.
Because he was such an experienced diver, he had decided that he could execute a better plan than the standard one via the marker buoy. He had not thought it through to the point of figuring out what we were going to do with that buoy once we went down the line to find him--was he going to go up, deflate it, and then come back down and try to find us again?
The standard plan works just fine for all divers at all levels. If all 5 of us had followed it instead of only 4, we would have lost maybe 5 minutes of our planned dive in the process--instead we lost the entire dive. In less benign conditions, we might have lost the diver.
