Diver dies on French Reef (Keys)

[spoolin01]

Most boats in the Keys do deploy current lines when moored where there is current. I don't believe they usually let out 100 yds of line.

That's reassuring to hear, an earlier poster made me think it wasn't customary there. I don't think we know whether they surfaced directly down current, perhaps that's likely, but even at that, the difference between a long swim and a short swim improves the odds and the will. Maybe it wouldn't have been the trick in this case, but it might well have been.

BTW, you won't be looking for two SCUBA divers in full gear at 100 yds. You'll be looking for two heads at 100 yds.

This is really the element I quibble with, reducing it to a 'head' only. Not 'full gear' - I didn't mean they were walking on water! If they're swimming, you can see plenty of BC/tank or diver upper body, depending on attitude and the type of BC. If they're floating vertically, there's mask/snorkel and most often pieces of the rig. Often bright colors. ...Even assuming water conditions are such that opacity blocks the sub-surface image as they rise and fall with the sea state, and that they're not signalling. The searcher can improve his odds as well.

Better diving,
Mike

 

[spoolin01]

the sun was low in the sky, and made searching in that direction almost impossible.
...
Betcha couldn't, even knowing they were out there.
Rick

Not my original hypothetical, not known at the time of your first post , but you're reassessing your odds, maybe that means I'm making headway! I'll take a 4PM sun in late Oct scenario, just to keep it real.

Better diving,
Mike

 

[spoolin01]

Because drift/tag lines 100-200 yards long would quickly end up being less than 30 yards long in the Keys due to other boats chopping them up with their props.

That would be funny if it is true and were not such an unfortunate calculus.

Better diving,
Mike

 

[Walter]

This is really the element I quibble with, reducing it to a 'head' only.

Why? The head is almost all that's above the surface and that's usually all you'll see.

Not 'full gear' - I didn't mean they were walking on water! If they're swimming, you can see plenty of BC/tank or diver upper body, depending on attitude and the type of BC.

Sometimes, you'll be alble to see some of the tank or BC, but it'll be very low in the water and not easily seen.

If they're floating vertically, there's mask/snorkel and most often pieces of the rig. Often bright colors.

Mask and snorkel do not make the head easier to see, it's still a tiny target a long distance away. Bright colors are far from universal, don't count on them.

Even assuming water conditions are such that opacity blocks the sub-surface image as they rise and fall with the sea state, and that they're not signalling.

I must be missing something, what's the rest of your thought?

The searcher can improve his odds as well.

How?

 

[spoolin01]

Why? The head is almost all that's above the surface and that's usually all you'll see..

Really not my experience, I have to disagree. Divers usually inflate their BC pretty well esp if they're not going to swim, esp in choppy water. If you're swimming, more is typically visible.

Sometimes, you'll be alble to see some of the tank or BC, but it'll be very low in the water and not easily seen..

I'm just pushing for the concession that it subtantially increases the cross-section and other factors affecting visibility, over just a head.

Mask and snorkel do not make the head easier to see, it's still a tiny target a long distance away. Bright colors are far from universal, don't count on them..

At the margin, I'm going to insist they do. The bar is pretty low here when comparing to 'head' only. Angles improve visibility. While not universal, white/green/pink greatly increase visibility, even in small doses. Even a plain mask has a good chance of standing out due to contrast. A female diver greatly increases the odds of bright color.

I must be missing something, what's the rest of your thought?.

Just that visibility doesn't go to zero right at the water's surface, especially if sea state periodically raises the person in relation to immediate foreground.


Take a plain head - add 2X or 3X in cross section and quite a bit more contrast in color and shape, and the visibility question changes a lot.

How?.

Binoculars, polarizing lenses, height.

 

[K_girl]

Boat anchoring entry and exit methods in moderate to strong current:

My last visit to Key Largo last May - found a couple of different practices on mooring the boat in strong current. First - is a down-line right off the stern, with the stern facing into the current, minimizing time and distance on the surface for the diver. When all the divers are in the water, the boat moves where you come up the line off the bow with the bow facing into the current. Divers go down the side of the boat where the current will push them into the boat and follow the boat to the stern for exit, with a tow line in case the diver overshoots and use for removing fins. This is the easiest method for the diver, a little more work for the boat operator. I tend to favor boat operators who do this, which I've found to be the smaller boat operators.

Second method is the face the bow into the current for both entry and exit, run a tow line on the stern and a granny line to the front of the boat (hopefully, all the way to the anchor line). Boat stays in the position the whole dive, makes more work for the diver, less work for the boat operator. The larger boat operators tend to favor this method.

 

[Doubles]

Mike

Your not getting me to reassess the odds related to the probability of detection of persons in the water.

Binoculars and polarizing lenses are all good tools to have, height helps - but at the end of the day even a person wearing a bright orange type I PFD is going to look like a coconut floating in the water from a helicopter hovering at an altitude of 500 feet. Add some sun, a white cap or two, 2 - 3 foot seas and we are back at square one again. Which means your pretty much invisible.

Swimming, BC's fully inflated etc etc is not going to add enough cross section to improve the POD.

Snorkels are not going to add to your visibility - I really think you are reaching here.

One thing I did not mentioned in earlier posts is that if you want to improve your visibility, add some reflective tape to your safety sausage/smb's - especially for night diving

Cheers

Steve

 

[John_B]

Second method is the face the bow into the current for both entry and exit, run a tow line on the stern and a granny line to the front of the boat (hopefully, all the way to the anchor line). Boat stays in the position the whole dive, makes more work for the diver, less work for the boat operator. The larger boat operators tend to favor this method.

IMO this is not just about less work for the captain, its also a safety issue when you have five or six boats tied off to mooring lines as closely together as you may find in the Keys (and I'm thinking specifically of Molasses and French reefs). The less time the props are spinning over a reef with divers in the water, the better.

As for granny lines, except for ripping currents on deeper dives (Grove, Duane) most dive ops in the Keys just have the divers do a blue water descent directly from the tag line off the stern, and then swim off into the direction of the current.

 

[dave4868]

Mike

Your not getting me to reassess the odds related to the probability of detection of persons in the water.

Binoculars and polarizing lenses are all good tools to have, height helps - but at the end of the day even a person wearing a bright orange type I PFD is going to look like a coconut floating in the water from a helicopter hovering at an altitude of 500 feet. Add some sun, a white cap or two, 2 - 3 foot seas and we are back at square one again. Which means your pretty much invisible.

Swimming, BC's fully inflated etc etc is not going to add enough cross section to improve the POD.

Snorkels are not going to add to your visibility - I really think you are reaching here.

One thing I did not mentioned in earlier posts is that if you want to improve your visibility, add some reflective tape to your safety sausage/smb's - especially for night diving

Cheers

Steve

Agree completely.

The difficulty of discerning a diver in a choppy sea is often underestimated until one has struggled with it a few times. In low light or glare, success can become a matter of pure luck. That kind of experience brings a new respect for one's limitations.

At similar distances and sea conditions as described in this thread, I've been amazed more than once how hard it was to see a 15" orange tuna ball despite knowing what quadrant to scan. "I KNOW it's there...."

And that was with no glare.

We often wouldn't see it until we closed the distance substantially.

Dave C

 

[wilde100]

Important point on the securing the sausage. I have a nice metal clip to attach it to my BCD. Should I have something else? (Seriously, I really don't know. I just assumed the clip was enough.)

Thanks for the info on the folding snorkel with velcro. I don't think that would be as annoying as my stupid monster big hard plastic one.

Please also consider how you will deploy the SMB with reel.
New divers sometimes get distracted underwater just trying to deploy it, taking with it risks of uncontrolled bouyancy.

Worse, if you loose grip of the reel, it might just unspool all the way to the bottom.

I've known divers who make little knots on the first 5- 8m of the reel, every meter, to let them know how deep they are when they deploy. Something else to consider.