Divers missing near Marsa Alam?

[String]

I suspect if the current were light enough for anchoring to work without being dragged under it'd be light enough for them to swim to the reef/boat/shore.


FWIW i always carry at least one reel - how else would i send my dsmb up.

 

[Yury]

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Please help us to find witnesses! This is the case of emergency.
There was a dive-accident on January 6th, 2007 at 9:00 a.m. in Red Sea at reef Elfinstone (25 km to north-east from the seaside resort Marsa Alam). Four divers still have not been found.
We know there was a boat or yacht near Elfinstone at that time, presumably with divers onboard. Those guys may help us to get urgent information on that accident.
Please contact us if you know them or something about that yacht.

Emails: help@webdive.ru
Blogs: http://leenq.livejournal.com , http://elhard.livejournal.com (blogs are in russian, but you may post comments in english that is perfectly ok!)
ICQ UINs: 481633 (Alexei AKA leenq)

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[victor]

Not really. Line length doesnt matter.

Assuming the line is long enough eventually you will be pulled to the end of it by the current. Then due to the forces it'll start to pull you under.
Its entirely to do with current strength not line length.

By your logic all boats at anchor would sink if there was a current.

If the line is nearly vertical say 85 degrees then a small horizontal force 10 lbs creates a large vertical force of 114 lbs, so you would need a big wing to stay afloat.
If the line is at 45 degrees then a horizontal force of 10 lbs create a vertical force of 10 lbs, any BC should provde this if you have dropped your weight belt.
If the line is at 20 degrees then 10lb force creates a vertical force of 5.6 lbs.
if the line is at 10 degress then less.
The vertical force = horizontal force divided by the tangent(90 - angle)

 

[UnderSeaBumbleBee]

Yury, welcome to our online diving community. I so wish it could be under happier circumstances that you would have found us. Our thoughts and prayers go out to you, your dear friends that are missing and their families.

 

[Diving Doc]

Just to repeat what Leah has said. So sorry you are talking to us under such circumstances and hope you can find some sense out of all of this.

 

[String]

By your logic all boats at anchor would sink if there was a current.

No they wouldnt. You clearly misunderstand the very basic physics involved.

You're entirely forgetting the strength of current and the drag created by the diver in the water against that current. Which induces a further force eventually going down.

The effect of the current on the line is its trying to pull it in the same direction, ie flat and horizontal - and as the anchor point is on the bottom the part angled up and float is also pulled down.

You dont even NEED physics to verify this. Go somewhere where they have strong currents. Witness pot buoys get dragged under by currents. Go diving in those areas - you know when slack arrives as the buoys pop up.

Its well known established fact.

Actually, i notice you're in the UK. Go for a dive in the Severn, tie the rope nice and securely to your BC. In a few days the coastguard can come and pull your drowned rotting corpse out and theory would have been proven.

 

[victor]

String
Sorry to disagree but I do understand the physics involved very well.

The physics of anchoring a boat and a diver are identical, boats don't sink at anchor if it is done properly and neither would a diver.
The stronger the current is the more rope you need or the more lift you need.

Using your argument all buoys would sink if there was any current at all. As there is nearly always some current all buoys would be no use as they would spend there time at the bottom of the sea.

Take the example of very shallow water say 2 metres and 100 metres of rope.
The pull of the rope is almost parallel to the force generated on the diver by the current. So there is no downward component, so you would net sink.
Now take an example of the buoys you mentioned earlier where the rope is almost the same as the depth. in this case the robe behaves in a simillar manner to the punch bag, as the buoy gets pushed it immediatly starts to sink.

As I stated earlier the forces involved are
The vertical force = horizontal force divided by the tangent(90 - angle)

If you still don't understand then I sugest you look at
http://www.glenbrook.k12.il.us/gbssci/phys/Class/vectors/u3l3b.html

 

[Yury]

Thank you very mutch for your wishes!

We hope that the lost divers will be find in good health...

Regards,
Yury

P.S. Sorry for my English...

 

[UnderSeaBumbleBee]

Yury, no worries about your English. You do better than many who were born speaking English.

I hope that our discussion about anchoring/sinking/ rope length/ what went wrong on the dive and so forth hasn’t offended you or the other friends and family members of the missing divers. On Scuba Board we talk about these sorts of things and try to learn from them so that we will be safer divers. Sometimes when family members come across them, they are offended and think our discussions are cold and callous without thought of the missing or injured diver. It is certainly not our intent to show any disrespect to your dear friends and their very serious situation.

If you would like to post some information about your friends to let us get to know them, through your eyes, it would be a welcome part of the discussion. We would welcome the chance to hear about your friends and why they are so dear to your heart. From reading your posts, it is clear that they matter a great deal to you and even though you are posting in another language, the message of your care, concern and love for these divers is not lost in translation. I am sure it would mean a great deal to your friends for them to know that you have spent time on the Internet researching on how you might help them and imploring others to help if they can. Having a person like you in their life who really cares must be of great comfort to them. I hope some how a miracle returns them to you.

 

[Jai Bar]

Yury, no worries about your English. You do better than many who were born speaking English.

On Scuba Board we talk about these sorts of things and try to learn from them so that we will be safer divers. Sometimes when family members come across them, they are offended and think our discussions are cold and callous without thought of the missing or injured diver. It is certainly not our intent to show any disrespect to your dear friends and their very serious situation.

Perhaps that is the reason why it is always better to split accident threads to condolences to the families and technical, cold, discussions trying to understand what happened and how other divers can learn anything to avoid such cases.

I have just heard news of yet another fatality in Sinai- a solo, advanced tri-mix, diver who died after failing to complete his decompression stops on a 110m dive..

If something happens only once, it is a matter of luck. Second time is coincidence, third time it is a phenomenon. The number of fatal incidents during technical dives in Egypt in the last year is way far beyond luck or coincidence. I hope they put themselves together and start doing things better over there :shakehead