Catastrophic Failure - How much weight to drop? Theoretical Discussion

[divingpyrate]

You hit the surface with a nearly empty tank and a BC that would not hold air and you view this as a situation that requires you to signal "distress" ...What was the nature of your distress? I am confused? Why would you not put your snorkel in, hold the smb and then relax as you wait for the boat to pick you up?

Guess you would have had to be there Dumpster, and maybe you missed the part about carrying weight in a thread about ditching weights.
wont justify a battle of words with you over my situation at the time.
I am quite sure your excellence would have handled it much better

My point for the others not looking to pick it apart
dont try and swim weights at the surface

 

[3D diver]

Just to stir the pot, and out of curiosity, how many of you have actually experienced an out of air incident? Not a planned exercise, but exhale, try to inhale and get nothing?

I did once, but it was 'cause a friend of mine turn off my air while I was tooling around in my parents pool. It was quite a feeling, even knowing I only had to go up 5 or 6 feet. At depth, on a real dive? Yikes!!!

To really try for troll status: Any of you read about the USS Tang? WWII sub that got hit by it's own torpedo. It's the only known instance where survivors attempted to escape and swim to the surface using the Momsen lung---a hood with a limited air supply, basically you re-breath your own air on the way up. It did not go well...

http://en.wikipedia.org/wiki/USS_Tang_(SS-306)

Carry on...

 

[koozemani]

Just to stir the pot, and out of curiosity, how many of you have actually experienced an out of air incident? Not a planned exercise, but exhale, try to inhale and get nothing?

I did once, but it was 'cause a friend of mine turn off my air while I was tooling around in my parents pool. It was quite a feeling, even knowing I only had to go up 5 or 6 feet. At depth, on a real dive? Yikes!!!

To really try for troll status: Any of you read about the USS Tang? WWII sub that got hit by it's own torpedo. It's the only known instance where survivors attempted to escape and swim to the surface using the Momsen lung---a hood with a limited air supply, basically you re-breath your own air on the way up. It did not go well...

http://en.wikipedia.org/wiki/USS_Tang_(SS-306)

Carry on...

your own link indicates that several survived the ascent. How did it not go well?

 

[3D diver]

The first escape attempt went badly, one sailor left before the safety line was deployed, got hung up in the decking and died. The rest (4 or 5 per attempt) were so traumatized by the equalisation procedure (flooding the escape chamber) they didn't even try and returned to the compartment.

More than half the folks who tried the escape died on the way up or on the surface. There were tens of sailors in the compartment who didn't make the attempt.

There are a couple of good books on the subject.

You can read the Tang's patrol reports, and those of all the WWII subs here:

Historic Naval Ships Association - Submarine War Patrol Reports

Real history, written at the time, by the brave men who lived it!

EDIT: Most of the survivors were on the bridge or in the conning tower and made it into the water before it sank. One sailor escaped from the conning tower into an air pocket on the bridge, spoke with another sailor there, then made a blow and go ascent---the only documented case of that, as well. (according to what I've read).

The torpedo hit the back of the sub and it innitially sank with the stern on the bottom and the bow above the surface. The survivors flooded some ballast tanks to level the ship on the bottom both so the escape chamber could be used and because the Japanese were hunting for them. They destroyed some sensitive equipment to prevent it from falling into enemy hands and burned some secret documents. This, unfortunately, started a fire which limitted the amount of time available to try the escape.

and my appologies for drifting so far off topic.

 

[dumpsterDiver]

Guess you would have had to be there Dumpster, and maybe you missed the part about carrying weight in a thread about ditching weights.
wont justify a battle of words with you over my situation at the time.
I am quite sure your excellence would have handled it much better

My point for the others not looking to pick it apart
dont try and swim weights at the surface

I had to be there?

I have no idea what you are talking about. So your advice is to ditch all your lead (and allow it to come raining down on the divers below) if you ever have a problem with your BC on the surface?

BTW: I myself have had a few BC failures, I reported one in this thread:

http://www.scubaboard.com/forums/accidents-incidents/365071-bc-failure.html

 

[Frosty]

I only read the first page but given the diver has air in his tank then why not inflate the bc or dump some weight if thats not an option.? The diver is heading to the surface with a fairly full tank which means theres time to ditch some weight

 

[boulderjohn]

Over the past year or two we've seen quite a few divers make it to the surface by various means and then drown with their weights on. And basically zero dead divers due to weights ditched at depth leading to uncontrolled ascents and AGE therefrom.

Have you ever seen a stressed diver on the surface struggling to stay afloat because they forgot to inflate their BCD? Unfortunately I have all too many times.

Yes, there have been cases in which OOA divers have made it to the surface, been unable to inflate their BCDs because they were OOA, and then drowned because they lacked the strength to stay afloat by kicking.

Let's remember how a weight check works. A diver doing a weight check WITH A FULL TANK should float at eye level while hold a normal breath and not kicking at all.

Anyone who gets to the surface with an empty tank and is unable to stay afloat is very seriously overweighted. They should not be able to submerge!

What percent of your vast majority do you think can make a 100' ascent on a single breath while under stress without absolutely rocketing to the surface. Say you go up at 120' per minute, how many divers realistically can manage that breath for the required 48 seconds under stress? Granted SB'ers are a different sort, but I'd wager few run of the mill vacation divers could. This whole discussion is about a hypothetical situation.

I agree that just about everyone should be able to do this, but what if they don't?

A tank that does not give the diver air at 100 feet is not empty. It just does not have enough air to provide it at the standard 140 PSI above ambient pressure. Once the diver goes up a couple of atmospheres of ambient pressure, an inhalation will be rewarded with welcome air. The closer the diver gets to the the surface, the more this will happen.

 

[ozzydamo]

You can't breathe water.

If you need to dump, you need to dump.

A better investment would be O2 for the car. If you do experience a free ascent from 99 ft, you're probably going to come up a'bubblin'. Therefor, the faster you get on O2, the better.

U don't think buying a pony to dive with would be wiser??????

---------- Post added April 13th, 2013 at 04:29 PM ----------

Dropping lead is not necessarily going to be sending anyone rocketing...Depends on the anount of lead worn, the amount ditched and many other factors. If you are at 100 feet, you have no buddy and no redundancy, your regulator just popped off the hose and you did not realize it until you exhaled.... you have a problem. I personally would drop my weight belt, kick gently, attain a considerable ascent speed, stop kicking, try to relax and as I approached 30-40 feet (assuming i felt good) I would flair out and spread eagle and decrease my ascent rate.,, maybe even start venting the BC if I felt like a bad ass that day.

This is far more workable than dicking around with trying to blow air (you don't have) into a BC.

Also, even if the diver did pass out from low oxygen levels on the ascent, they would reach the surface in a bouyant conditon where they might resume breathing on their own and would be "recoverable" for several minutes.

So you wouldn't first put your alternate reg in your mouth and ascend calmly (maybe even folding the hose of your primary and pocketing the second stage), while looking at you spg; noticing the rate at which your remaining air is going and how far your have to ascend to be safe....

---------- Post added April 13th, 2013 at 04:38 PM ----------

Just to stir the pot, and out of curiosity, how many of you have actually experienced an out of air incident? Not a planned exercise, but exhale, try to inhale and get nothing?

I did once, but it was 'cause a friend of mine turn off my air while I was tooling around in my parents pool. It was quite a feeling, even knowing I only had to go up 5 or 6 feet. At depth, on a real dive? Yikes!!!


Carry on...

Maybe not turning your air on fully or a buddy turns it the wrong way and puts a half turn back and get to a depth where your first stage no longer gets enough air to keep up with demand; this happened to me, I calmly ascended, no drama- I do my own check ever since and never use my regular buddy do anything (he's Irish), I will check a new buddy if they ask kindly.

The only other thing I could imagine is a complete First stage failure(which I have never heard off happening), and wouldn't simply carrying a pony bottle rectify that situation????

Be lucky if 50% of recreational divers knew how to thread a tank cam band correctly.

Let alone skin-dive in a proficient manner- lots of basic diver skills have been lost due to the technological age- Y-gen are a bunch of theoretical geniuses(google it!)......Z gene will only be worse, so keep the body bags at the ready(mortician is looking like a future proof career choice).