TSandM -- Her Greatest Posts

[LanceRiley]

She was lost at sea a couple years ago.

omg... im sorry to hear that.. rip and condolences.. I was away from scuba for 3-4 yrs...

 

[bowlofpetunias]

Lynn's refereed to the "Incident Pit" fairly often. It was certainly a concept that stuck with me and I felt justified my cautious approach to problems that arise around diving. I have thought of posting some of them here for well.. years now. I did a search..Incident Pit and used name TSandM and there they were.

predive checklist

There's a concept called the "incident pit", where the idea is that accidents are kind of like ant lions' lairs. At the beginning the funnel's pretty wide and not very steep -- you can take one step in and probably turn around and get out. But each step you take puts you on a steeper slope, and closer to being eaten at the bottom. Starting a dive without a designated buddy and without a dive plan, and without any pre-dive communication about descent and buddy strategies, puts you a couple of steps into the funnel. Executing the dive without any communication about gas supply, and being randomly assigned a buddy late in the dive, puts you another couple of steps in. Luckily, you had the final skill of sharing gas (and enough gas to do it) that kept you from the ant lion's jaws. But there's a good saying that "A superior diver uses his superior judgment to avoid having to use his superior skills,' and there is a huge amount of truth to that. When you DO find yourself salvaging a really bad situation, the best way to make that situation truly useful is to sit down afterwards and try to figure out how you could have avoided it in the first place.

Scuba diver dies after being found floating at Kurnell, NSW, Australia

I think, what I can put together of the story is a beautiful illustration of a concept we call the Incident Pit. It's kind of like the traps that the ant lions built, where there is a conical slope of sand that end with the ant lion's jaws. If an insect puts a foot or two into the pit, he can probably get out; the further down he goes, the more inevitable the outcome becomes.

IF we have unfamiliar gear and overweighting, that's one step into the pit to begin with, and one which may not have been recognized. Unbalanced rig with inadequate wing lift is a second step. Resubmerging with limited gas is a third. Separating from buddies is another -- you're now WAY down the slope, and all it will take is one or two small things to finish the process. An out of air from an inaccurate gauge, followed by a desperate attempt surface while overweighted, could have resulted in an embolism. Getting to the surface and being unable to get positive could have resulted in drowning. The autopsy may shed light on this, but I think the very, very sad truth is that an extremely experienced diver, diving in experienced company, looked at a benign site and wrote off a lot of potential negatives, and the only person who had the perception to call her on it was the least experienced diver in the group. Which is a VERY interesting piece of information.

Of all the accident threads I have read on this board, this one may have the greatest learning potential for all of us.

 

[Saniflush]

This is a great analogy. Thank you for finding and re-posting.

 

[bowlofpetunias]

Air consumption for new divers. I have provided the link and quoted the entire post. The specific reference to breathing is later in the post so click to expand. Worth reading this enirely

Air consumption tips?

You really have thought it through well. The biggest improvements in air consumption for new divers come with increasing efficiency. Being efficient means maintaining neutral buoyancy without a lot of BC adjustments (which means proper weighting, too). It means streamlining your equipment as best you can, and reducing movement, including the very inefficient use of the hands. Reducing speed, avoiding exertion like swimming against current, and in Coz, reading the reef for places where you can shelter and stop for a bit, are all part of being efficient.

One thing you may not have thought about is trim. If you are horizontal, any force you generate with your kick is driving you forward (or backward, depending on the kick). But if you are at an angle from the horizontal, two things happen. One is that you are presenting a much larger surface area to forward movement, which increases the resistance and therefore the effort required to move in that direction. The other is that your kick is no longer directed forward -- some component of it (increasing with the degree of head-up trim) is driving you UPWARD. To counter that, new divers have to remain slightly negative, so that they do not move steadily shallower. In other words, you're kicking yourself upwards and having to sink to avoid rising; all of that is wasted exertion. Being horizontal and neutral reduces the effort, and also allows you to stop whenever you want, without having to swim circles around the object you want to view.

One great test for this is simply to stop kicking and glide for a moment. If you start to sink, you know you were not neutral when you started the exercise. (Frog kick is a great kick for this, because there is a glide phase built into each kick cycle, and that glide phase is a constant buoyancy check.)
The very last thing you should think about is your breathing. It IS true that the most efficient breathing pattern on scuba is different from what you probably use when sitting at your computer. On land, we do not have to worry about making efficient use of the gas supply we have. In the water, we definitely do. With each breath we take, we move air through structures that participate in gas exchange (the air sacs in the lungs, or alveoli) and through structures which are simply conduits (the trachea and bronchi). We MUST move a certain amount of air through the alveoli, to maintain a normal carbon dioxide level in the blood, which is very important to the body (and the brain). Clearly, many small breaths will result in ventilating the bronchi (dead space) multiple times, and fewer, larger breaths will result in the same amount of air through the alveoli, with fewer exchanges through the dead space. So slower is better, right?

Not quite. The problem with slow, very deep breaths is that, particularly for big guys, the lungs are a very large air space affecting buoyancy. Taking a slow, very deep breath is like filling your BC up, and you will rise in the water column. If you then exhale strongly, you will fall. Those excursions CAN be big enough to begin the process of expanding the air in your BC, so that, if you inhale deeply, when you exhale, you may not stop rising -- then you have to adjust your BC and start the cycle over again.

There is a rhythm that allows you to take a deeper-than-normal breath, and release it just as you begin to move upward, and then begin to inhale again just as you begin to move downward. This is the rhythm that the "fin pivot" exercise in OW class (if you did it) is designed to help you find. It's a breathing pattern that is more like meditation or yoga than normal land breathing, but it is not composed of huge breaths. I think that, more than anything else, this particular thing takes time to master -- and even more time to learn to maintain, even in the face of distractions or anxiety. But breathing is the key to neutral buoyancy, and neutral buoyancy is the key to efficiency, as well as being one of the most delightful and seductive things about diving.

Hope this was helpful! (It was certainly LONG )

 

[billt4sf]

How to Deal With Current:

First off, the important thing is not to panic. Water is stronger than any of us, and given a strong enough current in any direction, we are not going to be successful fighting it head-on. But if you have gas to breathe, you have time to solve the problem.

All diving problems are better dealt with in prevention than in reaction. If you are diving in an area known for strong currents, you will want to close up your spacing between you and your buddy. Currents are often laminar, and if you are 15 or 20 feet away from your buddy, you may end up in a layer that is moving faster and creating separation. Watch the structure, too. If you have been behind a rock or a hull that is sheltering you from the current, and you are about to leave that, you will be caught and blown. Prepare by closing up with your buddy and checking the location of the guide, if you are following one. In fact, watching the guide more frequently is often helpful, because they know the sites and choose their route to minimize the effects of the current.

Recognize the behavior of water. As I said, it's laminar -- water right down on the bottom will almost always be moving more slowly than further up in the water column. On a wall, close to the wall is better than further out in open water. Hide from the current as best you can; even small irregularities in terrain can help a lot.

IF you are blown off . . . First thing to do is to try, if you can, to get the attention of the group to let them know what has happened. In sunlit tropical water, this can be very hard to do. Tap your tank with something -- even yell into your regulator, as that sound will carry. As everybody else has said, once you have tried to angle or otherwise make your way back to the group and found you can't do that, give up. Fighting current is a good way to lose your resource that is buying you problem-solving time, which is your gas. At this point, you have both a team separation and a separation from the boat, and that's bad. You have decided you can't repair the team separation, but you can at least minimize the consequences of losing the boat. This requires learning the skill of deploying a surface marker buoy. If you can shoot a bag right then and there, the boat is likely to see it and realize they have a diver heading off in the wrong direction. It's my personal opinion that bag shooting is one of the necessary prerequisite skills to diving in high current areas.

Similarly, if you are on the surface, try as hard as you CAN to get where you need to go, but if you can't, don't struggle into exhaustion. Make sure you are buoyant. Get the attention of the group and of the boat -- see if they can throw you a tag line. Inflate a surface marker to make yourself easier to spot. If no one has noticed you are drifting away, wave the marker, yell, or use an audibly signal device like a DiveAlert (one of those saved our butts in the Philippines last year).

These things do happen. I've been caught in powerful and completely unexpected currents a few times. I have had several occasions to be extremely glad of the signaling devices I carry. Just always remember -- underwater, if you have gas, you have time; on the surface, if you are buoyant, you have tons of time.

 

[scubadada]

Wow. We'll never know what happened

 

[Kevrumbo]

Wow. We'll never know what happened

Lynne left in her own words an assurance but nevertheless worrisome clues from an incident seven years ago, which can be construed as possibly contributing or as precipitating cause leading to her disappearance -->She had a history of acute positional Vertigo in diving:

I have lived with vertigo since I began diving. My first few charter boat dives ended in ascents where I lost my buddy and I was absolutely sure I was doing somersaults in the water. I couldn't fix it, so I learned to do my somersaults at 15 feet . . . I have learned a whole host of strategies for preventing vertigo, and some for coping with it when it occurs, but the absolute best way to prevent and correct vertigo, regardless of the cause, is a good visual or tactile reference. If I can see my buddy and my buddy is stable, it helps ENORMOUSLY. The solo diver does not have this immediate and excellent resource. Even nowadays, if I lose sight of my buddy and get vertigo (and that's the usual cause now, is looking for someone who isn't where he ought to be), I have trouble maintaining position and buoyancy control.

.. . .If you have a weakness, don't ever think it's been overcome. It can sneak back and bite you at the most unexpected times. Constantly work on the things where you have problems . . .

I don't have any issues with vertigo in any setting other than diving. But I have a lousy sense of balance -- I could never walk a balance beam in school, even if it was only 4" off the ground. I'm intensely dependent on my eyesight for orientation, apparently, and when I'm deprived of it (or when the visual input doesn't make sense, as inside a wreck that's lying in some weird position) I'm a bit of a mess.

It takes a very definite set of circumstances to get me into trouble these days. I have to be in midwater, in poor viz, in motion (not just hovering), and lose sight of my entire team. Thank goodness, all those things together don't happen very often.

Lessons learned:

1) I KNOW I can't search for a buddy in midwater. I shouldn't have tried. If you can't stay where I can see you, you need to stay where you can see me, and be aware that it's YOUR problem at that point.

2) I got it stopped [Vertigo]. I could never do that before. I have gained tools from other training that were directly applicable here. No training is ever wasted.

3) It is useful to be able to decide quickly what the biggest danger is. In this case, it was being too shallow. Being too deep I could deal with, and was going to be limited in any case by the hard bottom. Once I decided shallow was bad, I knew what I could do to avoid it, even if I didn't know where I was . . .

. . .I don't think it's necessarily the case that no one should look around on deco -- but if you're susceptible to vertigo, as I know I am, it's a definite risk. Most divers I know have never had vertigo, and often don't even understand what I'm talking about when I describe what happens to me in midwater. . .

. . .It is true that probably the most common cause of vertigo while diving is unequal pressure in the ears. Mine is not due to this, because it can come on quite suddenly while remaining at the same depth. But it does seem to be related to rapid head movement. . .

. . .And yes, I can use the bubbles going up each side of my head to stabilize myself, as well as how my feet feel in my drysuit and how my gear feels on my body. But it takes a little time to check all those things and integrate them, and during the few seconds it takes me to do that, my personal experience is that I am tumbling violently. It's very unpleasant. Of course, the kicking and clawing I do actually CREATES the instability I think I have (but don't), so it's really important to suppress the urge to do those things. . .

. . . But for the time the vertigo was going on, I have everything I can do to cope with it; there was nothing left with which to think of signaling anybody. . .

. . .We don't learn without stretching a little, but occasionally the ocean bites back and tells you [that] you overestimated yourself . . .

Vertigo on deco

 

[billt4sf]

Lynne left in her own words an assurance but nevertheless worrisome clues from an incident seven years ago, which can be construed as possibly contributing or as precipitating cause leading to her disappearance -->She had a history of acute positional Vertigo in diving:








Vertigo on deco

WOW! *I* have acute vertigo, though never while diving!

 

[Akimbo]

Currents are often laminar,..

I generally agree, except at small choke-points like the one of the two openings to Puget Sound and San Francisco's Golden Gate. OK, the bottom currents can be a little less but are still screaming. I have even been in current in excess of 5 knots on the bottom in open sea off South Carolina. I wouldn't have believed it but that is what the Captain calculated it based on our hot-jump and pick-up points. It was before GPS so measurements were based on Radar.

Hang-off for decompression was impossible so we had to hang off a small drifting inflatable at our 20' O2 stop. The dive was useless except the ride was rt of fun.

 

[Peter Guy]

I am truly amazed that two years later people are still discussing Lynne's posts.

I'm convinced she had no idea anything like this could be happening but she'd be proud as hell that it is.