If you are a new diver, please read this

[Teamcasa]

As soon as you bring cubic feet into the discussion, you've lost a large percentage of your audience. <snip>

The average 40 year old in this country can not come close to performing well on standardized math tests. In 2 days of class room time the average person is not going to be doing algebra problems using cu^3ft/s.

Your disesteem for the average will someday come back and surprise you.

 

[TSandM]

Scuba math involves such difficult concepts as multiplying by four and diving by ten. Almost anybody in the Western world is going to eat in a restaurant from time to time, and calculate 15% of the bill for a tip. Come on, people! Even a diver I know who is dyslexic and has severe problems with math has mastered gas management calculations. It took some work. So does learning buoyancy control.

 

[MXGratefulDiver]

Scuba math involves such difficult concepts as multiplying by four and diving by ten. Almost anybody in the Western world is going to eat in a restaurant from time to time, and calculate 15% of the bill for a tip. Come on, people! Even a diver I know who is dyslexic and has severe problems with math has mastered gas management calculations. It took some work. So does learning buoyancy control.

... and many divers don't master buoyancy control either, because they believe it's too hard ...

It truly does boil down to motivation ... if you believe something is hard, or unnecessary to learn, you won't learn it ... even if it's completely within your capability.

On the other hand, those who believe it's important will always learn it ... some will discover that it's a lot easier than they thought it would be.

Fact is, most people never learn gas management ... not because it's hard, but because their agencies and instructors don't think it's important. And so they pass that belief along to the student.

I suppose the majority of those who you rely on for dive instruction think that a few OOA casualties every year is "acceptable" ...

... Bob (Grateful Diver)

 

[Blackwood]

The average adult in this country admits to not understand how to balance their checkbook.

The USA has one of the worst education systems in the developed world, particularly in areas of mathematics.

The requirements for graduation in most school systems is entry level algebra.

The average dive student is approaching middle age, meaning they have not had to do basic math in many years.

The idea that the average student can easily handle basic math problems is a huge assumption that is not supported by evidence.

I don't believe that the math involved in these simple calcs is above any average adult human being, no matter what their educational background.

I could teach it to a 9th grader.

In 2 days of class room time the average person is not going to be doing algebra problems using cu^3ft/s.

Yah, I wouldn't think so. 9th dimensional math is probably beyond most humans (again, regardless of their educational background)



However, anyone capable of understanding miles per gallon and miles per hour is capable of understanding ft³/min. I'd assert that most everyone of legal driving age applies.

 

[Teamcasa]

Fact is, most people never learn gas management ... not because it's hard, but because their agencies and instructors don't think it's important. And so they pass that belief along to the student.

This is the real issue.

So many instructors are just parroting what their instrustor taught them and testing at the minimum of agency standards.

As a result, divers that what to learn more and become more proficient divers seek out other training avenues like DIR, GUE and many others. Then still we have many divers are perfectly happy diving once or twice a year while on vacation.

It is not a question of being smart enough, it is a question of do they know and dive enough to even ask the question.

 

[BettyRubble]

Having just finished my confined water portion of the cert, I can tell you it felt like alot of things were glossed over. I'm a bit anal about learning new things and had read 3 scuba books in addition to the manual before class, so I was surprised at what seemed like shortcuts. Don't get me wrong, it was a well run class, but I wonder if in the interest of attracting newbies to the sport, the 20 hours falls a little short.

On the ditching lead point --- it was a point I read alot in the books. So when I had trouble getting bouyant in confined water class I dropped my belt immediately. The instructor felt it was an overreaction, but frankly, I don't think dropping lead should be second guessed. Your point is perfect - if you are thinking of it, do it.

Don't know the experience level of the two divers involved in this (how sad), but as a newbie my greatest concern is that my lack of experience will put a 'buddy' in danger. Each level of diving requires a learning curve (OW, wreck, cave, etc) and it is my responsibility to manage that curve.

Praying for the families. Very sad.

My OW instructor told me that if I ever start to think about ditching the lead, then ditch the lead. I could then go find him at any point in the future and say, "Brian, I ditched my lead," and he would buy me new lead.



Never trust a computer with your life. I say this an a EE who has worked with globally-deployed life-critical systems. It's like those old reserve valves - it'll work fine for years until one day when it fails at depth. Be prepared and be ready to whip out an analog gauge.

I did note that the effects of cold have not been discussed in the gas calculations. Is the drop in temperature (and thus the increase in gas used per breath) not big enough to worry about unless you're cutting it razor thin anyway? It's late and I'm tired and I can't remember if the calculations are supposed to be in Kelvin. Oh, wait, yes, of course it would be Kelvin, so a change from 277K to 297K would be negligible. Never mind.

 

[ScubaDocER]

On the ditching lead point --- it was a point I read alot in the books. So when I had trouble getting bouyant in confined water class I dropped my belt immediately. The instructor felt it was an overreaction, but frankly, I don't think dropping lead should be second guessed. Your point is perfect - if you are thinking of it, do it.

If you are ditching lead in a confined pool session to correct your buoyancy then I agree with your Instructor, you were overreacting. If you are out of air and need to make an ascent to the top because there are no other divers around you to supply you with air, then I agree that ditching your weight belt and ascending to the top while exhaling is the appropriate thing to do.

Ditching your weight belt should not be your first response to correcting improper buoyancy. Consider the following :

Check to make sure your BC is properly inflated.
Recall how much weight is in your BC/weight belt and see if that needs to be adjusted.
Are you wearing an exposure suit and forgot to account for the additional buoyancy changes?
Has the weight on the weight belt shifted?
Were you trim in the water at the time you could not control your buoyancy?
Were you multitasking at the time?

There are several reason why your buoyancy may not be as it should be. Ditching your weights will not correct a buoyancy issue. It will most likely make it worse.

 

[BettyRubble]

Hi Anthony - I don't disagree with you except: I was overweighted, at the surface unable to get my head above even with kicking, instructors had their back to me, and my BCD felt tight enough to be fully inflated (turns out it was 2/3), I figured I could dive again or ditch. I figured in the OW, diving again wasn't going to be a good option so I ditched the weight. Got my head up and remained calm the whole time. When my instructor saw the weight belt at the bottom he just gave me a look. We talked later about the overweighting. He figured after using the tank air, the weight he added would have been fine. I wasn't in any real danger, it was an 9 ft pool and I had half a tank of air. But the experience taught me several things: 1) when switching from 3m to 5m suit, recheck weighting so instructor doesn't have to add weights!, 2) when someone adds weights to your system, know where they put them (better yet, add them yourself!). Instructor added clip weights, didn't tell me where he put them, 3) I didn't do a bc before going deeper, my bad, and 4) buy my own bcd unit and get used to it (I'm actually thinking of a wing unit instead of jacket style). Inflation/deflation should be 2nd nature. I suspect there were at least 2 dozen more lessons to be learned from it but I'm too new to recognize them.

I have alot to learn and appreciate your tips. Lord knows I don't want to be a diving statistic nor cause a buddy to be one.

If you are ditching lead in a confined pool session to correct your buoyancy then I agree with your Instructor, you were overreacting. If you are out of air and need to make an ascent to the top because there are no other divers around you to supply you with air, then I agree that ditching your weight belt and ascending to the top while exhaling is the appropriate thing to do.

Ditching your weight belt should not be your first response to correcting improper buoyancy. Consider the following :

Check to make sure your BC is properly inflated.
Recall how much weight is in your BC/weight belt and see if that needs to be adjusted.
Are you wearing an exposure suit and forgot to account for the additional buoyancy changes?
Has the weight on the weight belt shifted?
Were you trim in the water at the time you could not control your buoyancy?
Were you multitasking at the time?

There are several reason why your buoyancy may not be as it should be. Ditching your weights will not correct a buoyancy issue. It will most likely make it worse.

 

[ScubaDocER]

Hi Anthony - I don't disagree with you except: I was overweighted, at the surface unable to get my head above even with kicking, instructors had their back to me, and my BCD felt tight enough to be fully inflated (turns out it was 2/3), I figured I could dive again or ditch. I figured in the OW, diving again wasn't going to be a good option so I ditched the weight. Got my head up and remained calm the whole time. When my instructor saw the weight belt at the bottom he just gave me a look. We talked later about the overweighting. He figured after using the tank air, the weight he added would have been fine. I wasn't in any real danger, it was an 9 ft pool and I had half a tank of air. But the experience taught me several things: 1) when switching from 3m to 5m suit, recheck weighting so instructor doesn't have to add weights!, 2) when someone adds weights to your system, know where they put them (better yet, add them yourself!). Instructor added clip weights, didn't tell me where he put them, 3) I didn't do a bc before going deeper, my bad, and 4) buy my own bcd unit and get used to it (I'm actually thinking of a wing unit instead of jacket style). Inflation/deflation should be 2nd nature. I suspect there were at least 2 dozen more lessons to be learned from it but I'm too new to recognize them.

I have alot to learn and appreciate your tips. Lord knows I don't want to be a diving statistic nor cause a buddy to be one.

I am glad that you made it through alright. My concern was for divers reading this, especially new divers, to feel that ditching their weight belt was a means of correcting buoyancy issues. There are a few issues I would take with your Instructor though.

They should have kept a better eye on you since they added weights to you. They have no way of knowing if the additional weights would be effective, or in this case, dangerous, since you could not even break the surface even while struggling. If they "had their back" to you, then they neglected their responsibility of supervising you which could have been fatal. Don't be deceived about the fact that you were in 9 feet of water. People can panic and drown in 9 feet. Given his lack of supervision over you and the options you were faced with, I agree that ditching your weights was a reasonable option. Your Instructor talked to you about over weighting. I would have talked to him about the importance of watching over his students.

If they are going to add weights to your system, they should tell you where the weights are. Seems as if you found out why. I agree that the last person to touch your gear should be you. That assumes however that you know what you're doing. In a teaching environment, the Instructor should know how to assist you with the assembly of your gear, this includes your weighting systems. What he could have done was hand you the weights and showed you how to put them on to demonstrate how to put on clip on or drop weights.

I agree with the other lessons learned but would extend a caveat to one of them. The issue with correcting buoyancy issues is not necessarily a change in your inflation system. You do not need to go to a BP/Wings system to become proficient in your buoyancy skills. Learn how to dive in either system and your will be able to remain trim and balanced no matter which system you choose. If you are currently using a BCD, continue to practice with it and understand how it works. Understand how much air is needed to control your buoyancy at various depths. Once this is accomplished, then you can consider a switch to a BP/Wings. Just a suggestion.

Sounds as if you are keeping a positive attitude about the experience and I think that is one of the best lessons learned from my perspective. As long as you have the desire to continue to improve on your diving skills you will be just fine.

 

[drbill]

To not teach such critical information seems foolish to me.

Fortunately I've had enough experience to know my gas consumption diving various profiles and can pretty well estimate the time I can stay under without going below the 500 psi safety margin. Unfortunately that usually only comes with experience, so OW students and certainly AOW students should be exposed to this consideration.

I do have to recalibrate when I go to the tropics since I dive them too seldom and my air consumption is quite different under the warmer water conditions.