Catastrophic Failure - How much weight to drop? Theoretical Discussion

[koozemani]

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?

---------- Post added March 12th, 2013 at 05:56 PM ----------



If you had more experience, I think you would realize that for a VAST majority of divers, they need to be ditching lead, conserving energy and NOT trying to blow their last dying breath into a BC during an emergency. Most divers can not even orally inflate their BC on the surface when scared or stressed without a lot of difficulty.

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.

 

[danvolker]

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.

It is actually very easy to do, and is NOTHING like a 48 second breath hold dive going horizontal.....

At 100 feet, you have alot more than one surface breath in your lungs, and as you ascend, exhaling, you don't have the air starvation feeling a non-freediver would have 48 second in to a breath hold....Maybe if the diver is in full blown panic mode this might be dicey, but if you had ever practiced this ( like we did in the 70's and 80's), a 100 foot free ascent would be something you could choose to do with as much confidence as an air share drill. You just keep exhaling, air feels like it keeps getting created/manufactured in your lungs, and at least I never felt as if the air was no longer good air --- in other words, you don't get that feeling that you have to breath again.

And when we practiced this in the old days, it was usually a non-bouyant ascent where you would have to actually swim up....but with an inflated BC pulling you at high speed, it is even less of an effort. It is not hard to exhale the air out, regardless of the speed you ascend at--unless you are an asthmatic--and in that case, this is an issue of how it can be safe for an asthmatic to dive.....

 

[raftingtigger]

Posted a poll in the basic scuba section on dropping weights at depth. Go vote http://www.scubaboard.com/forums/ba...ghts-depth-unscientific-poll-ill-effects.html

It isn't about your philosophy, it is about have you ever dropped and did you have ill effects.

 

[koozemani]

It is actually very easy to do, and is NOTHING like a 48 second breath hold dive going horizontal.....

At 100 feet, you have alot more than one surface breath in your lungs, and as you ascend, exhaling, you don't have the air starvation feeling a non-freediver would have 48 second in to a breath hold....Maybe if the diver is in full blown panic mode this might be dicey, but if you had ever practiced this ( like we did in the 70's and 80's), a 100 foot free ascent would be something you could choose to do with as much confidence as an air share drill. You just keep exhaling, air feels like it keeps getting created/manufactured in your lungs, and at least I never felt as if the air was no longer good air --- in other words, you don't get that feeling that you have to breath again.

And when we practiced this in the old days, it was usually a non-bouyant ascent where you would have to actually swim up....but with an inflated BC pulling you at high speed, it is even less of an effort. It is not hard to exhale the air out, regardless of the speed you ascend at--unless you are an asthmatic--and in that case, this is an issue of how it can be safe for an asthmatic to dive.....

And the key is practice...

 

[danvolker]

And to put this in perspective, many of the old timer spearfisherman in the 60's and 70's, diving with the steel 72 with the 500 psi reserve valve.....would be doing there 80, 100 or even 140 foot deep spearfishing dive, and when they took a breath, and got NOTHING, they would pull the reserve valve, and know that they would have time to shoot ONE MORE FISH before they would be OOA, and then would free ascend...this was every dive, for many, on purpose.

It was easy, or this would not have been happening so often. Of course, in those days, divers did not dive overweighed, and most did not even use BC's.

 

[crosshairs]

recently was faced with the drop or not drop decision. I had ring on my inflator hose come loose during a dive. was not aware my BCD would not hold air until I hit the surface, ahead of others because I am an air hog. Fortunately I still had air, and could breath but was swimming 14 lbs of weight and an almost empty tank. It was very tough, and could have been a panic situation for some. I saw our boat near by as they were following the sausage that was sent up for my early ascent. Signaled distress and got ready to dump as I was indeed tiring fast on a low supply of air. The boat made it to me quickly and i was able to grab on to their side rope.

If I had it to do over, the weights would go as soon as I know the BCD was failing. Dont try and swim weight on the surface. I am 56 years old, and in average to good health. It was not an easy task swimming weights

it sounds like you were over weighted if you had an empty tank and were still sinking

 

[dumpsterDiver]

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.

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.

 

[antattack]

The theoretical problem has practical solutions, but they are different depending on they type of diving you are doing.

Ditch-able weight is handy for a panic'd diver at the surface or recovering a body at depth. I have had to drop a panic-ing divers weight belt at the surface and it works like magic. Never had to ditch weight for the second reason.

My primary plan for the theoretical problem you describe is always to swim up my rig and exit the water with all the stuff I brought in. Hopefully more (Still hoping to find a DSV!) I dive a dry suit and a wing and carry a lift bag at all times, and I have practiced using a lift bag for ascent. I have had a dry suit flood at depth, and other than being cold, it causes absolutely no problem with bouancy. In a wet suit, in warm water, the strategy would be the same- swim up. In cold water, in a 7mm farmer john wet suit, the process is first to curse the decision to wear a wet suit, then proceed to what is usually my backup plan.

I have a backup plan. If everything goes bad, I have 8# of my 28# ballast ditch-able in weight pockets on my single tank wing. For my doubles, I have an 16# ditch-able soft weight belt. My doubles are steel HP 100s, my single rig is either steel HP 100 or steel HP 80, and I don't change my weight strategy when I change 80/100 tanks. The 2# overweight with the single 80 is less risky than making changes to my rig and less troublesome. Diving is supposed to be fun!

If I needed to ditch with my single wing, I have the option of ditching 4#, and then swimming up. If I need to ditch more, great, I can dump another 4#. and that's my answer to your hypothetical. Ditch a little, swim up if you can, ditch a little more if I must and then swim up.

With the doubles, the strategy has to change. When using doubles, dumping weight is not a good option. Automatically, more of my weight is less ditch able because of the steel tanks, first stages and manifold. Automatically a greater percentage of weight at the beginning is variable since there is twice as much gas that will be expended. This means that at the beginning of the dive, I could ditch all of my weight and make a safe ascent, but at the end of my dive, I probably don't need to ditch any if I'm shallow, but ditching all of it at 100' probably won't make any difference when wearing a wet suit. If I balance my ditch able weight to match the gas variable, I'll wind up with all my optional ballast being ditch able (hence the 16# weight belt.)

In doubles, for me, the strategy has to be "don't ditch weight when under water." I need systems that will let me safely ascend without changing ballast under water when I'm wearing doubles. So the practical solution to your theoretical problem is to change the game- bring redundant bouancy control devices.

Not sure if that's right, but that's my practical solution to your theoretical problem.

 

[flots am]

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?

If they actually tried it, all of them could. It's less than a minute to the surface at that speed and because of our buddy Boyle, the air will just keep coming.

flots.

 

[antattack]

If they actually tried it, all of them could. It's less than a minute to the surface at that speed and because of our buddy Boyle, the air will just keep coming.

flots.

I've practiced this in open water from sixty feet with a one minute ascent. Absolutely do-able the first try. I'll go further and offer that every diver should give it a try as it will build confidence. I hummed "The Sailors Horn Pipe" with little stops for every note and a one beat break at the end of every line. ("I'm-Pop-eye-the-sailor-man * I'm-Pop-eye-the-sailor-man * I'm-strong-to-the-finish...")

When I hummed the song without little stops and the beat break every stanza, I exhaled to fast and sort of rushed my ascent. Something about the little one beat break at the end of every line helped everything slow down.

Anyway, if you hear that song underwater, I'm probably near you practicing.

---------- Post added March 12th, 2013 at 07:44 PM ----------

Incidentally, I offer the song idea because I think it matters. When you actually need to use the skill, having a crutch like singing a song reduces task loading by throwing some of the things you are doing into automatic. But that only works if you've practiced.