BoyaControlncy

[MikeFerrara]

3. I am 5'10" and 150# how much weight should I carry? I am fine at the bottom hanging out. It is ascending and descending.

We can't tell you how much weight you need. It's not only a function of your body buoyancy but also that of your equipment. What you should be doing is learning to adjust it in the water. Checking and adjusting weighting is a required part of the course.
The fact is that you can control a descent even over weighted. In the beginning of a dive you will always be overweighted by at least the weight of the breathing gas that you carry and for those divers who are carrying a lot of gas that can mean being very overweght.

Manageing that weight is a matter of weight placement and buoyancy control technique.

4. So if I get to the bottom this is where I should play around with ascending and gliding?
Maria

NO. NO. NO. What you state here is a good description of how it's usually taught and is in line with some of the advice that you've recieved here but I strongly disagree with it.

In my experience, teaching and learning buoyancy control is easiest when you start at the surface. The idea is to never get too negative in the first place. Hint...you can check your weighting and learn the right way to start a descent all at the same time.

When you start a decent you DO NOT need to dump all your BC air. Remember you are always overweighted by the weight of the breathing gas you carry. Dumping it all just leads to an uncontrolled descent and leaves you plastered to the bottom where you then have to fiddle with putting air back in again. That's backwards, makes no sense at all and there isn't any need for it. You dump just enough to get neutral at the surface. Then all you need do is exhale a bit and you're on your way down (dump a little more if you want to drop fast but that's for after you learn how.). From there you can slow or halt your descent with breath control...of course as your wet suit compresses you will need to add a bit of air to your bc in order to stay close to neutral.

When descending in this manor you can stop anyplace you wish and maintain that position. That's what diving is huh?

Another problem divers have with descents is that they have trouble keeping balanced...they tip back/forward or to the side and they move arms and legs to keep balanced...and essentially swim back to the surface. Getting your trim somewhat under control near the surface gets this taken care of up front. I find that's easiest to do by paying some attention to weight placement and spending some time learning and practicing proper body position on dry land before even going in the water. It helps even more if you have an instructor who will get you away from those goofy vertical descents. It's one thing to have your head higher than your feet if that makes equalizing easier and an absurd extreme to have students trying to control their descent speed when they are positioned like a torpedo racing for the bottom. Flatten out some. Not only will your descent be easier to control but when you get to the depth where you want to halt your descent (hopefully before hitting the bottom), you will already be in a swimming position. It also puts your fins behind you where you can use them for controlling position without shoving you back to the surface.

Don't feel too bad. The backwards way this stuff is usually taught wreaks havoc with lots of students and even hurts lots of ears. Having your buoyancy under controlled starting at the surface SAVES the ears and makes you look and feel like a diver in the water. Rocks drop to the bottom...divers go where they want.

 

[shakeybrainsurgeon]

The standard mantra is "no one can tell you what weight you need" and this is, philosophically true but ignores the fact that the new diver in a class of 12 people isn't afforded the luxury of trying out multiple weighting configurations and doing pre- and post-dive buoyancy checks for each. they have to start out with some idea of what their weight requirement is from the beginning. For example, if she starts out with 14 pounds and only needs four, and you do buoyancy checks at 2 pound intervals, they would have to do six weight exchanges and six buoyancy checks. If they did that for every student, it would take most of the pool time for a morning just for that. Is there something wrong with guessimating weight based on standard formulas at least as a guide?

Of course, buoyancy checks are essential, but there's nothing wrong with calculating the weight needed from the outset to save time. In my OW class, they simply eyeballed me and stuffed weight into my bc with no explanation of how or why except to get me down quickly, and we spent little time playing with it thereafter. It wasn't until I did a number of dives with an instructor after my OW dives that I had the luxury of trying many different weight configurations. This isn't right, but I suspect that this is more the norm for most group classes.

And does everyone agree with Mike's belief that we should not exhaust our bcs fully when submerging. Isn't that what we're taught, or am I mistaken? First, this seems unreasonable for new divers to accomplish. Second, the PADI definition of a proper buoyancy is that the diver, with an exhausted bc, should float at eye level with a lungful of air and descend SLOWLY with exhalation. If someone is sinking so fast that they need air in their bc even while descending to keep from plummeting to the bottom, they may be overweighted. Granted, as Mike says, you will always be a few pounds heavier at the beginning of the dive, but I still think it makes more sense (and is simpler) to have new divers dump their bcs completely.

I just pull the shoulder dump on my classic bc and descend, then hit the inflator if needed as I near depth... is this wrong technique?

 

[Scuba_Steve]

So what you're saying SBS is that since there isn't time to get basic weighting down, they shouldn't do it at all. I agree that how they did it in your class is typical it didn't do you any good, and other than saving time (time you paid for BTW), this really was a diservice to you. This is as basic a skill as any other skill being learned in class, so proper time should be given to weighting and trim.

What Mike is saying is that he can't tell from here how much weight she needs,....too many variables that are unknown. I am sure Mike could ball-park her pretty well if he saw her and her gear set-up, suit and all.

No instructor with any common sense is going to be out 12lbs either on their basic 'first guess'.

It may be a fine line between full dump and only dump enough to get you moving downwards, I don't know, but I think getting the other things he mentions down first would make things go a lot smoother and this particular point not very problematic.

I personally spend a pile of time on weighting and trim, proper desent and ascent positions etc, at the expense of skills that try to mimick (but do not work well in developing these skills) what it is we as divers are trying to attain. (IE fin pivots, hovers, improper descents and ascents, etc)

It also helps to not plant them on thier knees, which of course is helped a lot by the fact that we've spent a lot of time getting that weighting and trim right in the first place.

I think the basic OW course would be far better if we just spent 30mins of reg and mask R@R, and pretty much the balance on proper buoyancy techniques. It would sure fix a lot of the basic problems most divers have, and is the cause of most of the accidents I see.

 

[shakeybrainsurgeon]

No, I'm not saying that at all. I agree with you totally that a great deal of time should be spent on buoyancy and weighting issues before having people try to hover or other skills. I'm just pointing out that there is a difference between what should be done and what IS done. And that it doesn't hurt for the student to come armed with some rough idea of what they need so they can have some understanding of the issue. Simply saying "work it all out in the pool' is philosophically correct and no doubt many good instructors do this, but from what I've read in other threads and from my own experience, many come out of the pool sessions and even the OW dives with no idea, either in practice or theoretically, what their weight should be.

If it takes all morning to get everyone properly weighted, that would be time better spent than swimming underwater with a mask off or towing a tired diver a short distance (since, in PADI, a lot of those skills are repeated in the OW anyway). But things are what they are.

She says, if I'm reading it right, that she was given 14 lbs of weight, yet seems to be wearing only a swimsuit in a pool. This sounds way, way off to me for a 150 pound person. It's best not to assume that everyone knows what they are doing.

And Mike is right, in that the typical tank is about 4-5 pounds heavier full than empty, so that if we do a proper buoyancy check at the end of the dive, we will be 4-5 pounds heavy at the start of the dive. I simply question whether, for the average diver, this makes for an uncontrolled descent if we simply dump all the air out of the bc. But his experience is large, so I defer to his opinion...

 

[MikeFerrara]

The standard mantra is "no one can tell you what weight you need" and this is, philosophically true but ignores the fact that the new diver in a class of 12 people isn't afforded the luxury of trying out multiple weighting configurations and doing pre- and post-dive buoyancy checks for each. they have to start out with some idea of what their weight requirement is from the beginning. For example, if she starts out with 14 pounds and only needs four, and you do buoyancy checks at 2 pound intervals, they would have to do six weight exchanges and six buoyancy checks. If they did that for every student, it would take most of the pool time for a morning just for that. Is there something wrong with guessimating weight based on standard formulas at least as a guide?

Of course, buoyancy checks are essential, but there's nothing wrong with calculating the weight needed from the outset to save time. In my OW class, they simply eyeballed me and stuffed weight into my bc with no explanation of how or why except to get me down quickly, and we spent little time playing with it thereafter. It wasn't until I did a number of dives with an instructor after my OW dives that I had the luxury of trying many different weight configurations. This isn't right, but I suspect that this is more the norm for most group classes.

I don't see anything wrong with using rule of thumb calculations, guestimates or the experience of the instructor to pick a starting point. You need to take something with you into the water.

The PADI definition of neutral at the surface (floating at eye level) may or may not be "correct". If you can hover just below the surface, you are neutral for certain.

However, it makes little sense to try doing much diving before the amount and configuration is verified. It just leads to problems and bad habits AND checking and adjusting the amount is a required part of the class and a required part of each and every single PADI OW training dive. If the instructor can't find time to do it he/she needs to re-evaluate their class.

And does everyone agree with Mike's belief that we should not exhaust our bcs fully when submerging. Isn't that what we're taught, or am I mistaken?

This may be what is taught but it's not what, in my experience works best and standards certainly don't require any such thing.

First, this seems unreasonable for new divers to accomplish. Second, the PADI definition of a proper buoyancy is that the diver, with an exhausted bc, should float at eye level with a lungful of air and descend SLOWLY with exhalation. If someone is sinking so fast that they need air in their bc even while descending to keep from plummeting to the bottom, they may be overweighted. Granted, as Mike says, you will always be a few pounds heavier at the beginning of the dive, but I still think it makes more sense (and is simpler) to have new divers dump their bcs completely.

The problem with having new divers dump all their air is they often end up descending too fast, get behind and lose control. That's especially true when heavy exposure protection is worn and about time the diver gets going down the suit is losing buoyancy fast and their speed increases quickly and they really have trouble catching up. Carry that technique foreward to a diver carrying more gas and/or more equipment and the situation only gets worse.

Keeping control of your buoyancy from the beginning works under all conditions.

Granted, I started out teaching it that way too but in the process of training I don't know how many hundreds of divers, I found having them keep control of their buoyancy at all depths worked much better. It's something that a gravitated to in search of a solution to a problem. The OP is a good illustration of some of those problems.

It's only unreasonable if your in a hurry to get the students to the bottom. On the other hand, why go to the bottom if you aren't yet in control? If you aren't in control, the best place to be is near the surface and I'd prefer to keep student very shallow until then.

The result is a class full of students who can descend in a very controlled manor, staying with a buddy and no hurt ears.

I just pull the shoulder dump on my classic bc and descend, then hit the inflator if needed as I near depth... is this wrong technique?

Wrong? Not if you are able to maintain control but control is the issue. If you dump more than needed only to have to turn around and put it back in, you're not doing anything to increase control. I can dump everything, drop quick and still stop where I want even when I am weighted down with 30 pounds of breathing gas but I've had lots of practice.

Try this...Descend with a buddy and stop every five feet staying together. If you can do that, I'd say you have a good handle on things. Use buoyancy control rather than your fins to control depth and maintain a constant distance from each other. What we see too often though is one diver stops (like if they have ear trouble) and the other diver plumits down and ends up in the bottom waiting. Not good.

Descents and descents are the first application of buoyancy control and two of the most critical times to have control. They are two of the times during a dive where problems are most likely to occure and being in control over movement in ALL directions leaves you best prepared and able to respond. In fact many of those problems are directly related to the inability to control the ascent or descent in the first place. This is every bit as true for a diver on their first dive as it is for anyone else and is probably only that much more critical for the new diver.

IMO, going deeper or going diving before this is squared away is just putting the cart in front of the horse. The fact that PADI likes or that many instructors do is not evidence that it works well.

 

[GDI]

Go back to the dive shop and tell them YOU want additional pool work You may need to pay extra but it will most likely be worth it. Get with the instructor you feel most comfortable with. Tell the instructor you want to work on buoyancy. When you feel you get the buoyancy down without moving then do some basic skills like mask removal and replacement while staying neutral. Do the skills as flat to the bottom not on the bottom as you can. Resist pitching up or moving other parts of your body.

Here this page from mywebsite may help:

http://www.genesisdiving.com/buoyancy.shtml

In short get all the equipment on (including a wetsuit common to your area of diving) and drain the tank down to about 800-700 psi, remove all the weight and all the air from the BCD. See if you can sink. Most likely not. Breath and watch what happens and how far you move. Now add the weight back on starting in 2 -3 lbs increments. You can increae 1 lbs by removing a 2 lb and then upping to a 3 lb, when you think you are close try to sink. remember try to sink with NO WEIGHT at first.
Once you can sink then lay flat on your stomach. Breathing normally see if that lifts you off the bottom. Add only the amount of air to the BCD as required to clear the bottom. Now float without moving, no sculling or any fin action - just FREEZE and Breathe. Just blink your eyes and breath. This will tell you if and how the weight is balanced. From here you can adjust the weight to get the trim down. Buoyancy and trim are two different things. Good luck If you have any questions PM me

 

[MikeFerrara]

If it takes all morning to get everyone properly weighted, that would be time better spent than swimming underwater with a mask off or towing a tired diver a short distance (since, in PADI, a lot of those skills are repeated in the OW anyway). But things are what they are.

It doesn't need to take all morning but, in general, I've found that the time spend getting weighting and trim taken care of to some degree up front saves time later so it works out.

I'd rather not try to have students doing much swimming around underwater if they're not weighted and trimmed well. They just don't learn much from it.

She says, if I'm reading it right, that she was given 14 lbs of weight, yet seems to be wearing only a swimsuit in a pool. This sounds way, way off to me for a 150 pound person. It's best not to assume that everyone knows what they are doing.

The PADI rule of thumb calculations are based on body weight and type of exposure protection. The problem, and the PADI literature points this out as well, is that people come in lots of body types. I'm about 145 and when I'm in shape, I sink because I'm lean and on the muscular side. Some people are 150 and all fat and they float like a bobber.

And Mike is right, in that the typical tank is about 4-5 pounds heavier full than empty, so that if we do a proper buoyancy check at the end of the dive, we will be 4-5 pounds heavy at the start of the dive. I simply question whether, for the average diver, this makes for an uncontrolled descent if we simply dump all the air out of the bc. But his experience is large, so I defer to his opinion...

We see it all the time especially in OW classes. Go to a local dive site and watch some. What we see is what I call "the infamous butt first plumit". Not only have I seen it a lot but I've had a few of them plunit tank first onto my head, LOL

But remember, that 4-5 pounds heavy at the surface isn't taking the buoyancy of the exposure protection into account. A diver, wearing a 2 piece 7 mil suit might be wearing 20 pounds of lead. Once they get down a ways and that suit starts to compress, they can get pretty negative pretty fast. In a pool or very warm water and just a swimming suit, the 4-5 pounds by itself may not be too unmanageable. Once those students put on those 7 mils and head out to the real dive though, it's butt first plumit time.

 

[shakeybrainsurgeon]

Thanks Mike. Personally, I think PADI should add a pool dive just for weighting issues...it would make things easier for the other skills. When I did the pool, we had one instructor, one AI and two divemasters for about 12 students. We used a community pool rented to us for three and a half hours only each session --- we had to be out on time for paying customers. We barely had time for everyone to do the required skills before we had to pack up. The divemasters simply played a guess your weight game, stuffed the weights in and splash we were off (Hey Jack, got any 2 pound weights over there? No... well, we use a few 3's then). I was overweighted the whole time, in retrospect. We did buoyancy checks, but no one was looking at each student to see if their descent rate was too fast or too slow. I'm not blaming the LDS, I think that's the practical reality of the course for most dive shops. We consumed almost a whole morning getting people checked out on air sipping, a useful skill, perhaps, but not as commonly needed as good buoyancy (hopefully).

 

[GDI]

Thanks Mike. Personally, I think PADI should add a pool dive just for weighting issues...QUOTE]

This is the instructor 's thing and the Pool availability not PADI's. PADI doesn't care how many pool sessions you have

 

[shakeybrainsurgeon]

Thanks Mike. Personally, I think PADI should add a pool dive just for weighting issues...QUOTE]

This is the instructor 's thing and the Pool availability not PADI's. PADI doesn't care how many pool sessions you have

I didn't know that, thanks.