A+, Tim... Clearly, there's a leadership issue, as is often the case in commercial diving. The problem is that nobody really knows squat until they're down there and they start seeing, doing, and figuring things out. Even the best-laid plans can get completely derailed by something as simple as, "Hey, there's no real definable bottom here." The problem in the above scenario is that you're the only one that realized it... The "helper" diver was so unaccustomed to commercial diving (despite his vast experience as a recreational diver), that it didn't even dawn on him that there'd be a problem once he got into the muck.
What's worse is that there's like $5k on the line here, for about an hours' work... So you're REALLY motivated to make it happen, even if the entire situation is a little hairy.
The PADI Open Water diving manual clearly states, "never use your BC as a lift bag," and also says that anything more than 10 lbs should be supported by a lift bag, not the diver's BC. The reason is this: If you drop the item, you're bound for an uncontrolled ascent. An uncontrolled ascent may be managable if it's a couple of pounds, but a 15 or 20 pound cinder block, combined with maybe 5 pounds of chain? Not likely. Embolism, anyone?
The RIGHT way to accomplish this task was to have surface support lower the cinder blocks with the chains attached by rope, then swim down the rope and connect everything together. That way, there was zero chance of an uncontrolled ascent, which was good... We were already inundated with lots going on already - zero vis, lots of current, and a very important job to do (this situation actually happened to me last Thursday).
By the end of the day (we installed a total of 5 cinder blocks), we realized that surface support was even LESS skillful on the water than my "helper"... So *I* carried the last couple of cinder blocks down, after using the chain to attach them to one of my D-rings so they couldn't be dropped. Thankfully, I had enough reserve buoyancy in my wing to support everything at the surface, so it was simply a matter of "flying" it down into place and then adjusting my own buoyancy neutral before disconnecting the chain - all while buried in the muck.
...Not that that was the perfect solution, mind you, but it got the job done and seemed to be the least of all evils. You know, when there's big money at stake you tend to do what you have to...
As for the leadership issue... Thankfully, the other diver and I were able to discuss things and see eye-to-eye on the way to do things... So we've become good friends, and our "team" has really flourished through mutual respect and understanding. Hopefully I'll be able to rely on him as a diver in the future.
