PART 1 OF 2
Since Rex asked this of me directly, I'm happy to answer (and it's going to be a long one). I'm sure some of the posters who are comprehension-challenged will mangle and mis-interpret what I'm about to say but hopefully it may give some additional perspective to the rest of you:
Ken I understand your logic when a diver is missing underwater. But when a diver goes missing how do know for sure they are missing underwater or missing on the surface?
You don't and you certainly do do both searches.
A rudimentary surface search, at least of the immediate area, can be done fairly quickly with eyes (multiple people) and binoculars. You would also likely be hoping that a diver on the surface (Drifting Dan is a good example of this), alive and not unconscious. Also during a visual surface search, you may spot their bubbles and now know where they are and that they're alive. If the bubbles are moving (hopefully back towards the boat), then they're just overdue. If the bubbles are stationary, they're either not aware they're running late or they may be stuck/trapped. But now you know exactly where to go to find out what's happening.
And for those who do not regularly dive California, bear in mind that we're frequently diving in kelp beds. The bubbles rising up through the kelp may dissipate. It's a lot harder to spot bubbles in the kelp canopy than in non-kelp area. Plus, if you've got any surface rippling, that complicates things too.
One other note for you non-CA divers: The diving style here is
NOT like most tropical or warm-water dives where the boat may be relatively small, everyone jumps at pretty much the same time, everyone comes back at pretty much the same time (or at least is under the boat together as a group), and is led by a guide.
SoCal diving has anywhere from 6-36 divers on a trip, the gates are open for 30-60 minutes so divers can go in at any time, there may or may not be a "be back by" time, and you could be there long enough for a diver to jump, dive, come back, and jump again before the gate closes.
The point of stating this is to give perspective to some who have implied/wondered "How could they not know someone's overdue?" Say we get there at 9AM, the gate's open until 10AM, and the be-back time is 11AM. Say a diver goes in a 9:15. At 10:15 there may still be a dozen or more divers in the water around the dive site. So which set of bubbles should we think are those of the "missing" diver? Or where should be look if we think the diver's in trouble? Because it's not like every diver files a flight plan before jumping.
Back to the art of searching . . .
The underwater search I think is the more critical of the two because there's no question that if the diver is underwater and not breathing, we don't have a lot of time to find them. The odds of success are slim at best. In my 35 years of diving SoCal, I can't recall a single instance where a missing diver was found, brought to the surface, and survived. (I think Frank alluded to a similar experience in one of his posts.)
To underscore how difficult it is to find someone quickly, when I used to teach Rescue regularly, we did a drill during a beach dive (average viz 5-10 feet) where the class and I started on the surface. I would then submerge (they were on their honor not to watch my bubbles) and would swim a random pattern for five minutes. I'd then stop and settle to the bottom. (We also agreed that I wouldn't be deeper than X or shallower than Y.) Then the rescue class would submerge and had five minutes to find me. At the end of that time, everyone would surface. In all the times I ran that drill, I was never once found. It's really hard to find someone underwater in five minutes or less.
I think another misconception may be that if you radio in that there's a missing diver, help will immediately be on the way. Not necessarily. In the specific case of Ship Rock, yes they're close (Isthmus Baywatch). But that's the exception, not the rule.
We were at Santa Barbara Island one time (about 45 miles offshore for those not familiar with SoCal), and a diver on the surface after the final dive had an apparent heart attack while kicking back to the boat. My DMs were on him within a minute and got him back to the boat within another minute. The boat captain had radioed USCG and we started CPR. It was over an hour until the helicopter arrived to do the hoist. We continued CPR the entire time. (Additional info - [1] No, the diver didn't make it, and [2] No, we didn't get sued.)
When you radio in, it's not like they say, OK, we're on the way." First they're going to go through an entire checklist to get info about the diver. Most importantly, they're going to want to know if you're getting a pulse or not because they're not going to "rescue" someone who's already dead. Once they've got the info, they pass that over to their Flight Surgeon who makes a determination as to whether or not to authorize the helicopter to launch. Once that authorization is given (I don't know at what point in this timeline the helicopter crew starts prepping), then they've got to get out to your location. And even once on site, they've then got to co-ordinate with the boat captain so the boat's facing the right way for wind, the deck has to be secured, they need to lower their rescue swimmer on board, he will then do an assessment of what's what, a basket will be lowered, diver loaded in, basket hoisted, rescue diver hoisted, off they go . . . and then it's another 20-30 minutes (or more depending on where you are) until they reach a chamber.
So none of this is like you might have seen it on TV or imagined it in your mind.
[TOO LONG FOR ONE POST - PART 2 FOLLOWS]