Accident at the Blue Hole!

[Jouskari]

In any accident there is seldom only on contributing factor. As in this case there were atleast four. The adopted safety procedure, The divers actions, the lan-yard and the dive line setup. Non of these singulary triggered the accident.

First of all, safety cannot be contributed to only one set of equipment like a tennis ball or a lan-yard. There always has to be as redundancy plan for any possible failure in the used safety system. e.g. Training what to do if the lan-yard tangles etc.

Second, any lan-yard will tangle as long as it is made from a cord (of any material). As a cord twists it will start to loop immideately as tension is realeased from it. A loop like that is perfect for looping around a tennisball or the bottom-plate or even the rope. Therefore one of the most important precations when using a lan-yard is to make sure it is not twisted before or during the dive. I strongly advice using a stopper like a tennisball etc. on the decent line. With the lan-yard usually being over 1 m and the bottomplate around 20 cm. I belive it is even more common for the lan-yard to grab the plate.

Third, I belive the proper action in this case would have been to immideately use the lan-yard quick-release and drop-any weights (that is why they also need to have a quick release). However, as in this case, narcosis and lack of training usually result in poor judgment.

Also I would like to add that, as I´ve posted many times elsewhere in this forum, that an Online videofeed from the bottom would also have expedited the surface safety measures. Technically it shouldn´t be to hard to do. Just incorporate a videofeed into the diveline ans seal the whole display package in watertight container on the surface.

 

[ericvrp]

However, as in this case, narcosis and lack of training usually result in poor judgment.

What makes you say that his narcosis resulted in poor judgement or that he had a lack of training? Sergio does no write about how much narcosis he had. Nor does he tell how often he is training in Dahab. And he writes (first post of this thread) that not releasing the lanyard was the right decision (according to himself).

To me it looks like after Adel's accident and Michael's near accident people imprinted in their mind that one should not remove the lanyard.
This might be the exception to the rule.

 

[Jouskari]

What makes you say that his narcosis resulted in poor judgement or that he had a lack of training? Sergio does no write about how much narcosis he had. Nor does he tell how often he is training in Dahab. And he writes (first post of this thread) that not releasing the lanyard was the right decision (according to himself).

To me it looks like after Adel's accident and Michael's near accident people imprinted in their mind that one should not remove the lanyard.
This might be the exception to the rule.

Well, ok, releasing the lan-yard might have resulted in a worst case scenario that he would have blacked-out closer to the surface if anything else would have gone wrong. But basically, if you release your lan-yard after a 5-10 s. struggle you should have enough margin to make it to the surface. Its not gona be a white card, but you will make it if you have planned the dive right and have the needed experience. Instead, pulling at a 6 kg bottomweight for a while and the blacking out at depth doesn´t seem as sound procedure to me. That is why I assume that the situation had not been trained or/and was influenced by narcosis. Also, instead of trying to swim up, I belive pulling up using FIM should also be used. This would at the same time work as a alarm for the surface crew.

But true, I don´t know enough about the incident so anything stated is just based on speculation.

 

[esom]

Second, any lan-yard will tangle as long as it is made from a cord (of any material). As a cord twists it will start to loop immideately as tension is realeased from it.

may sound like a smart ass´ comment, maybe it still helps. i know what you mean, but:

any material starts to loop as tension is applied to it.

 

[Kars]

Usually, nearly all problems are a result of a stack of failings.
Safety is about decreasing the chance of these failings.
I think many people could use more safety training, myself very much included! - when I get into the water, at last, I and a buddy so keen having some nice quality moments that I simply forget.


Ok I did a quick experiment, wrapping around my rope lanyard round a 16mm lamp post, simulating a diver corkscrewing himself down the line. I notice that with a each turn (rope held tense ) the resistance down is increasing. I does not have to be if the diver is close to the line, the windings can take place loosly and so the diver would not notice a braking effect. Now upon hitting the ball, the curled up line forms a near knot, and when going up it becomes a knot because the upward line pressing upon the underlying windings will prevent them from slipping.

Now for a solution I think a thick and short steel cable, that is fixed in a non moveable way to the carabiner is a much, much better design. The cable must behave so that it takes force to close the loop laying on a flat surface. In outer words, wants to spring open. With a short cable one needs less spring power = less thick cable, with a long cable it needs more thickness, adding to the diver's weight.

When one swims down with such a sping like cable, the cable won't curl up because the spring will have the carabiner end stay in line. Unless the carabiner has or gets much rotational resistance. These happen with some designs under extreme carabine to rope angles.

These spring properties make it impossible for me to store my lanyard twisted on my arm, but I'm sure I can overcome that little challenge.

What do you people think about the spring cable solution?

Any comments about the hockey ball idea?

 

[Bill]

I like the spring cable idea and I'd like to add another one. I used a version of the springy thing attached to a second weight belt and accidentally made the carabiner slightly positive. It worked well.

 

[Apneaddict]

At the risk of sounding like a complete snob... how about a polo ball?

They are larger than a tennis ball (more softball sized), are bright white and are hard plastic. I believe it would have to be modified to be just slightly negatively buoyant (drilled and filled with lead?)


I think it would be a safety upgrade to have a series of parts so that the "ball" simply rested on a small metal conical (pointing downwards) stopper - perhaps with a recessed void at the bottom for a knot to rest in.

This way IF the lanyard got looped around the line, the diver would not get stuck at the bottom and only be swimming up with the ball (with a large hole that is chamfered on both ends to allow it to easily glide up the rope), instead of having to drag the entire bottom plate / weight with him.

What do you think of this system?

System 2:
Thinking about it more - the large bottom cone (8"-10" in dia perhaps?) could be 2 parts (top and bottom halves) that screw / fasten together and the knot would rest inside a void in the the cone which would have a hole through it for the rope to run inside.

No need for a ball and if made out of stainless could act as the weight itself!

 

[Kars]

The polo-ball is cool, maybe freediving needs to have a little more glamour?
LOL- it's general idea to prevent the lanyard go over the ball off cause.

I already have made myself a cone for a plate on my practice line. Though I have my weights hang about 1,5m lower, followed by a chain and anchor that holds the line on the muddy bottom.

I think a cone is also much better because it's easier to raise and will not sail to the side when raised quickly.

 

[Apneaddict]

What if I were to get something in this general shape cast out of lead?

The knot (inside) would hold the cone in place. No moving parts, cheap materials, etc.

It would just appear to be a rope... and then a cone, with no fasteners, exposed knots, etc.

It would be your bottom plate and double as your weight.

Kars could choose to put additional line below it as an anchor if desired.

I know a world-class mouldsman in my area. Any interest??

Your thoughts / feedback??

 

[Kars]

Well, a light and a ring to the side to attach tags to would be nice.

I don't like the flat top, I like it to be more hydrodynamic, cone or dome shaped.

 

[Apneaddict]

Polo balls came in today!
I've got to drill a home through them and get a "lead golf club swing weight" to rest on top to stop it from floating.

Should be more visable and safer than a tennis ball, if I chamfer the hole.

Also, see my idea for a conical bottom weight. What do you think???

I want to get it 90+% before making a mould for it.

 

[Apneaddict]

I've come up with a $20 solution that should eliminate (or greatly reduce the chances of) this specific type of accident from happening.

We have learned that the tennis ball and / or a knot can get hung up on a lanyard. This knot / ball is the "stopper" and the bottom plate (if used - i only want to use it for competition, as it slows retrieval) in my opinion should be 1.5m away, so there is no chance of the plate or weights getting tangled in the lanyard.

So... We need a smoother ball with less chance of getting tangled that can rise up the line if it is caught... And we need to "streamline" the knot, to reduce its chances of snagging the lanyard. I'm putting an "egg" around the knot.











I haven't tightened all of the galvanized pieces down yet and I have to drill the polo ball and epoxy the weight onto it still.

I'm going to tighten it up and grind the top and bottom into a more streamlined shape, to reduce snags.

I think this solution could be a real simple answer to reducing the chances of a deep entanglement.

It should get some lake experience in the next week or 2.

Feedback?

 

[Kars]

Nice reporting and work.

A little different then what I had in mind, ideally I liked to have the knot inside the ball.

 

[Apneaddict]

Only way to do that, would be to drill a hole in the centre, cut the ball in half, hollow it out and epoxy it back together again. It could still get snagged / caught this way too and be dragged up with the weight.

I wanted a free-sliding ball, in case it still got snagged.

2 lanyard improvement concepts / experiments coming in the next day ad well.

 

[Apneaddict]

My lanyard's got a "semi"





I don't think something like this could get wrapped around a line if i tried.

VERY high-tech and precision engineered....

It's a cut and straightened, wire clothes hanger and some electrical tape. I would tape the length of it before using it. The wire is approx the same diameter as the steel cable.

Advantages:
- Cheap
- Easy / available materials & "construction"
- user retrifittable to all existing lanyards in the world (if you pay shipping I will personally install for $50 per lanyard )
- No worry about strength, as it's just adding a backbone to the existing lanyard.

I actually think that if only the half nearest the caribiner is reinforced, it will eliminate the wrapping issue and still allow for some fore/aft movement as you swim down the line without feeling resistance on your arm.

Thoughts on this "modify / stiffen" the existing lanyard???

 

[Apneaddict]

another way to accomplish something similar would be to slide some heat-shrink tubing around the bare cable itself and shrink it while straight.

This would give the cable a "memory" of being straight and some resistance causing it to be semi-rigid.

 

[Kars]

How is the weight?

I like my lanyard to be very close to neutrally buoyant.

 

[Apneaddict]

its the same weight as your existing lanyard... plus that of a clothes hanger... minus the "hook"

 

[chrismar]

Or, you just release your lanyard if it gets tangled. Just throwing a radical, costly and complicated solution out there.

 

[Kars]

Preventing entanglement now needs some inventiveness. Once we've discovered the economic and practical ways I think it definitely is an improvement that helps in competitions, training and safety.
Just think of having any of the following: strong current, an entanglement, diving with only a noseclip in dark deep waters where you don't see surface light, and one has stress and narcosis. Or swimming, cnf, and you're rotating and the lanyard wrap creates extra resistance you don't feel much because you're focused on other things.

Yeah I'll take the 'no wrap lanyard' anytime over a regular one.
It's a practical improvement, just like a shoulder seat-belt over a waist seat-belt.