Freediving Death...

[Jon]

I've got a few different floats.

My larger one for spearfishing is an OMEr America float. I use a shorter float line on it for spearing, since the fish in this area are shallower than others, and clip it off to the back of my belt. It follows me along just fine, with bi-fins, and holds all of my crap- water bottle, food, fish stringer, whistle, signal mirror, goody bag, camera and an extra mask just in case.

When I'm out diving in some deeper water, looking for anchors and stuff, I use a small wreck reel with about 140' of line on it. I can tie a small weight to it and have a nice guide line up and down. It isn't as easy to pull myself up as my 1/4" rope, but it does work and it packs super small. I can then let out about 15' and clip it off to the back of my belt for the trip home.

I also have bigger inner tube floats that I can attach bigger lines to, or my retrieval system, and it can hold a LOT of crap. I don't normally carry it with me since it's so big, but it is nice when your dragging home 30-40 pounds Worth of anchors and lost fishing gear.

What are others using when out freediving with their monofins. Or maybe I should ask what's the easiest way that you've found to pull a float when your swimming with a monofin? I find that the line keeps bumping my fin when clipped off to my belt.

Jon

[laminar]

Hypoxic or hypercapnic training?

I think both.

My CO2 tolerance and my comfort enduring contractions is high from my competitive days, especially on constant weight ascents. So is my hypoxic tolerance, although it probably is reduced from the levels I experience when I am actually training for competitions (which these days is never).

However, diving the way I do, I rarely enter into any need for C02 tolerance since I sink to the depth after only one or two gentle monofin strokes. The dive ends up being a static followed by an easy ascent. Not much CO2 generated there. That's why I have to really watch my ventilation so that it's neutral. Half the breath up is spent in 10-15 second cycles of static apnea.

As Eric, mentioned, it is good to know what it feels like to be hypoxic so you can judge your state after the dive and then plan the next one accordingly.

What I'm getting at is that if you have a tolerance for both low O2 and high CO2 but don't dive in such a way to find yourself experiencing either, you'll have an extra reserve for when a dive goes wrong. The caveat is that you must somehow maintain these tolerances through other means, whether its apnea or exercise.

When I ascend from a ugly dive I have the belief that I can handle at least 20 more seconds of hard exertion on a hypoxic and hypercapnic basis. More if I'm in good fitness shape.

Pete

[trux]

Originally Posted by laminar

What does your line look like? How thick is it? Where do you attach it to your body? Can you upload a photo of it?

At the moment I use a very basic inflatable buoy of a similar type as on the picture below. The line is I think just 3mm thick, in signal-orange nylon (just like on the photo). I just attached a 1kg weight to it, so that it floats with the flag straight up (there is a separate chamber that you can fill with water, sand or maybe some lead shot, but this was simpler and efficient). I am thinking about getting or constructing a real float - for example buying the one from Sevylor, but the advantage of the buoy is that you can put it into the side pocket of your fin bag.


I attach it to my belt - which is another important security measure I forgot to mention originally - in case of problems you won't hesitate to drop your belt, since you can retrieve it then easily again. Also, if you get tangled, or the line caught in rocks or corals, and you cannot quickly untangle you, or use your knife, you can simply drop the belt to get away.

As with all security tasks, I strongly recommend drilling it often - you should drop your belt, pull your knife, flood a mask, surface without using fins, drilling a buddy rescue (when you are with a buddy), each time you go out. If you do not do it, when you need it, you will either forget about such possibility, or panic and will not manage to do it properly or quickly enough.

When exploring some holes, small tunnels, or caverns, I attach it to a rock, or sometimes use a small anchor I also have - though by doing so you lose a lot of the security the float offers, hence I try limiting it to the necessary minimum.

Originally Posted by laminar

Dog leashes use a retractable line, but it has very thin line, not good for FIM. 30m meters of line might be too heavy to retract anyway.

Good idea; I may try one, but am afraid it won't keep more than two days in sea water. Are there no self-retractable reels for spearing or fishing? The resistance is not a problem - you can pull out as much as you need of the line before you dive; and retract it when you ascent, or only when you swim on surface.

Originally Posted by laminar

Have you ever been tangled in your line? How do you dive with it usually?

No, I have not really been tangled when diving (especially because I usually keep the line trimmed), but when swimming on the surface, since I use to stay directly at the buoy for security reasons, all the length of the line is around me - that's where it is the most disturbing, and that's why I want a reel.

The 30m of the line is not heavy at all, since it is quite thin. The line and the buoy are strong enough though that I can really pull on them to get up.

I already explained how I dive with it - when on surface I keep it close to may head; when I descend, I let the line slide between my fingers, keeping so the line in tension, and the buoy just overhead, and when surfacing I fin along it upward, or use it in FIM style to pull on it to the surface.

Originally Posted by laminar

I think that if you were diving with a buddy, having a float marking their location would be excellent. What about tangling though?

Well, I admit it may be little bit of a hassle, but I think it is manageable, especially because you should never go down both in the same time. Possibly you could have just one line and taking it always for the dive.

Originally Posted by laminar

Do you carry a knife usually?

Yes, of course, as I wrote in my earlier post, a knife or scissors are an important security tool. And especially, you have to be used to pull it quickly and handle underwater.

[foxfish]

Here is my float, I find a foam float works well because I can carry spare equipment on board. In fact my float was a surfboard that I cut to shape. I can coil my line around the board & lock it in place at whatever length I need.

[Fondueset]

Here I think we are pretty much legally required to have a flag. Boats are legally required to stay 200 feet away. Fun fact: The diver's flag was invented in michigan!

[deep thinker]

Originally Posted by trux

I am thinking about getting or constructing a real float - for example buying the one from Sevylor, but the advantage of the buoy is that you can put it into the side pocket of your fin bag.

Now that is a cool gadget to have
Strange what we as divers and spearfishers find would be good to have

[josedesucre]

I build my first float (many years ago) using an old aluminum bicycle wheel, from which I removed all the spokes, and weaved a net through the spoke holes. Then I tied the wheel in the center of a pneumatic inner tube. It was kind of heavy to tow, but it was sturdy, provided a lot of space to carry stuff, and I could even climb on it to rest if I wanted to.

[Fondueset]

I'm going to repeat an idea I think is pretty swell. For deep divers who dive with others - a timed strobe on your float set to go off after whatever you consider a reasonable interval. It would need an easy to activate button that would require no energy expenditure to press. Then - if your pal saw the strobe flashing he/she could swim to your float and pull you up by the floatline.

[ocean_314]

i should have been clearer in my post i dive solo when freediving but always with a partner when scuba.
With freediving why does one need a partner it never made much sense. If you get in trouble down 20 or 30 ft it will be at least 2 minutes before you are missed by your buddy. Then he will take at least another minute or two to find you, if you are lucky. Then another minute or two to get you out of the trouble and to the surface...woops not quick enough you are brain dead.

[trux]

The majority of freediving deaths are caused by Shallow_water_blackout (SWB) or Deep_water_blackout (DWB), which paradoxically both usually happen in the last few meters during the ascent. Unlike the name suggests, DWB does not happen at depth, but it is actually what many freedivers here mistakenly call SWB. Exactly taken though, SWB describes only incidents at dives where the maximal depth did not surpass 5m (not really freediving but rather snorkeling or spearfishing), while DWB describes BO during ascent from a deep freedive, due to depressurization and hence more sudden and intensive hypoxia in the final stage of the ascent.

Properly trained buddy will always come to meet you before surfacing, and will accompany you during the ascent to the surface, being ready to intervene immediately in case of need. If you black out, you'll be on the surface within few seconds, and there removing the mask and lightly blowing onto your face while quietly instructing you to breath, is in very most cases all what is needed to bring you back again. Often, experienced feediver may recognize symptoms of hypoxia before you black out and assist you to the surface quicker, saving you so from the BO.

All that can happen within very few seconds, but even if it took four minutes as you wrote, you'd be mostly still quite far from being brain dead. All this is the reason we are telling a buddy is extremely important in freediving, but having a buddy who actually knows what to do and how, is important even much more. Just being on the same location with another freediver is not what we call a buddy system - it is indeed more or less worthless, if not even more dangerous.

[jome]

What he said.

The unpredictable and sudden nature of SWB is the biggest problem. Because of the huge pressure change in the last meters, it is possible to feel "completely ok and in control", with no warning signs, and then in the last meters of ascent just boom - lights out.

This is not usually fatal if a buddy is there to catch you, but in almost every case when diving alone, it is. That's the big potato here...

Most of this discussion has revolved around wheather or not it is possible to dive alone in such a way that one can have enough of a safety margin to be relatively safe. I think the conclusion is that there are things you can do to make it safeR, but you can never be as safe as with a proper buddy system

[josedesucre]

EXACTLY. Precisely. Absolutely!

[efattah]

Originally Posted by trux

The majority of freediving deaths are caused by Shallow Water Blackout (SWB) or Deep Water Blackout (DWB), which paradoxically both usually happen in the last few meters during the ascent. Unlike the name suggests, DWB does not happen at depth, but it is actually what many freedivers here mistakenly call SWB.

I disagree. Shallow water blackout is a blackout which occurs near the surface, during the ascent from a deep depth (>5m). Deep water blackout is a blackout which occurs in the deeper phase of the dive, typically on the bottom or the very early part of the ascent.

Examples:
Shallow Water Blackout: A diver descends to 20m, stays there for some time, then ascends, and blacks out at 5m.

Deep Water Blackout:
- A diver descends to 25m, and remains there for some time, and blacks out on the bottom
- A diver descends to 70m, and starts to ascend, but blacks out at 50m

However, the true distinction really has nothing to do with shallow or deep. The true distinction is the different mechanism of blackout. There are really four types of blackout:
1. Hypoxia blackout (low oxygen)
2. CO2 blackout (too high CO2)
3. N2 blackout (too high N2)
4. Hyperoxic blackout (too high O2)

A shallow water blackout refers pretty much exclusively to #1. Generally, a 'deep water blackout' refers to #2, #3 or #4... for freedivers it would be most often #2.

[Tobbe]

Ok, so this Murat thing with early breathingreflex and high CO2 increasing the risk of a Deep blackout?

I have never heard of someone getting a blackout in depth.
But Eric wrote about someone who had.
How big is the risk of getting a Deep blackout (on the bottom, or in the early ascent)? It not seem bo be so ordinary, but it can happen.

[Bill McIntyre]

Originally Posted by Tobbe

I have never heard of someone getting a blackout in depth.
But Eric wrote about someone who had.
.

Well, I'll tell you about one.

On a spearfishing trip to Mexico, I found my buddy kneeling on the bottom at 90 feet with his head and shoulders under a ledge holding his shaft. There was no fish on the slip tip, but it seems likely that there had been.

Some people theorized that he had shot a pargo and passed out before reaching the surface, then been pulled back down. That would make it SWB, but I doubt that is what happened. He was perfectly balanced on his knees, and I find it highly unlikely that he would have been arranged that way if pulled unconscious back to the bottom by a pargo. I think he blacked out in place.