Buoyancy Issues

[bubba105]

To the OP, these things are to be expected. Once you get a little more water above you your breathing will have less effect. Hang in there, it gets a whole lot better.
Buoyancy for me was an ongoing battle. I could always keep from crashing into people and things but I dive with some masters. People with 7,000 to 10,000 dives. Now that's buoyancy. In trying to accomplish that zen stillness there have been many setbacks. Once I handed a divemaster a 2lb weight at depth, a pre-planned thing and then attempted a safety stop at 15 ft. I was like Sputnik until he gave me back the 2 lbs. Slowly the weight I needed dropped, my general comfortability underwater increased and each breathe decreased in volume. I don't know when it arrived but I have buoyancy, good buoyancy now. 300+ dives. Palau in May, this can only get better.

 

[MikeFerrara]

the thing is.. what is proper trim position... hovering is totally different to fin pivoting and hovering horizontally is a different skill to hovering upright

and i can guarantee you that 90% of new OW divers will be over weighted for there first few dives (if they are not i will make sure they are) this is to make sure they can kneel on the bottom so they can do there basic u/w skills.

Why should they be doing skills while kneeling on the bottom? This is diving that we're teaching right?

its one thing to say to a new diver.. just weight yourself properly.. or attain proper trim please..

its totally another to actually show them what your talking about and have them understand what your saying..

That's why we need tp be teaching it. Explain the mechanics of static and dynamic trim in the classroom. Talk about body pody positioning, how it effects trim, demonstrate and practice it on land before ever even getting in the water.

i would guess the total amount of new OW divers that get trim and buoyancy correct during there first OW course would be around 10-20% in my experience... as long as they understand what they are trying to attain then they are 99% the way to getting proper buoyancy in there diving.

Yep, most new divers don't get it but that's because their instructors don't get it and aren't teaching it. On the other hand, if it's taught in confined water where it should be taught, they'll all have it before even doing their first opwn water dive. the trick is spending confined water training time diving rather than kneeling.

 

[PerroneFord]

I don't necessarily agree with your posting, but I do thank you for the very calm, and logical manner in which you answered it.

You really do your safety stops vertical? When you are just hanging out in mid-water, observing students, are you vertical then as well? I tend to hover about 2ft above students as I let them explore. I'm close enough to assist if needed, but out of the way and out of mind as they work. I couldn't do this if I was vertical in the water.

When I was working with my friend a couple of weeks ago, she was having a tough time descending in 10ft of water (pool). She said she needed more weight. Instead I worked on her breathing, and stopped her from being vertical in the water and subconsciously finning. I made her cross her legs, and when she went to breathe out, she sunk like a rock. Thirty minutes later she was hovering mid water in a 10ft pool.

I really do believe we can teach new OW students about buoyancy and trim, without overweighting them. I believe we can teach all basic skills to OW divers without making them kneel on the bottom. My instructor has allowed me to test this theory out on his students and we've proven it can be done.

My question is why do we battle the priciple of primacy, and teach them something we are going to have to get them to unlearn shortly after class?

""I can say without question, that at no time, on any dive, did I ever have a need to hover upright. When do you find this skill helpful?""

Wall diving, saftey stops, drift diving, blue water diving are all the times when I would use "upright hovering".
About the only time I would use horizontal hovering is when diving on a flat bottom.

My need for "over weighting" students comes from, How do you teach someone to use a bcd inflator if they are netural? adding 4-6 lbs and explaining to them why then removing it I found works the best for me when teaching the fin pivot and hovering skills.
It also simulates what happens when you are wearing a wetsuit at depth swimming from shallow to deep when wearing 10 extra pounds, the problem is when the Inst. doesnt tell the students the reason for being over weighted in the first place.

 

[scubanatic]

What I have found over the years is that new divers do not relaize that their lungs are more bouyant than they want to believe. It is critical that you relax and fully exhale on the desent. Then when you are ready to establish your bouyancy just put a little air in the BCD and be patient. It takes time for the air to establish itself. Also, the 10% of your body weight may not always be accurate. It also depends on your body mass. Lean and Plump divers require sometimes more than 10% in the ocean especially with a 5 mm wetsuit. Muscular divers can probably get away with 5%.

The main thing is to relax and don't over think the skill. Practice makes perfect and you will have a great time! Good luck on your check out dives.

 

[SparticleBrane]

I believe the "10% rule" is ridiculous. I don't know anyone that uses that much weight unless they're wearing a lot of neoprene.

 

[Colliam7]

Several people already zeroed in on a possible starting point for addressing the issue. In reading your post my first reaction was, 'Sounds like he was just a little bit underweighted.' Don't strap on 24 lbs of lead but, if you can get in the pool again with your instructor, you might try putting some extra 1-2 lb weights on the bottom, and then adding weight in small increments to the pockets on your BC to fine tune your weighting. Just a thought.

The 6-10' depth we use for pool dives is, as others mention, a particularly difficult depth in which to maintain control. You may well find during your checkout dives, at 30 feet you have little trouble. Of course, I would NEVER publicly say this myself, but I have been told that many of us DMs who demonstrate skills in the pool at the Instructor's direction, tend to add a little extra weight to avoid just this kind of situation. Add to the depth the fact that not a few trainees tend to breath deeper and more rapidly just because of a little anxiety, and you find that having a bit of extra weight at the beginning is helpful. Over time, a new diver's air consumption and weight requirements both tend to decrease.

As noted, you will find bouyancy control improving with time. Just look at the people you were in the pool with, who were doing a refresher. Hang it there, and enjoy the checkouts in PR.

 

[MikeFerrara]

The 6-10' depth we use for pool dives is, as others mention, a particularly difficult depth in which to maintain control. You may well find during your checkout dives, at 30 feet you have little trouble. Of course, I would NEVER publicly say this myself, but I have been told that many of us DMs who demonstrate skills in the pool at the Instructor's direction, tend to add a little extra weight to avoid just this kind of situation. Add to the depth the fact that not a few trainees tend to breath deeper and more rapidly just because of a little anxiety, and you find that having a bit of extra weight at the beginning is helpful. Over time, a new diver's air consumption and weight requirements both tend to decrease.

The reason that some say that buoyancy is more difficult to control at shallow depths is because buoyancy varies with depth by a greater percentage closer to the surface. However, adding more weight, beyond what's really needed, only makes it that much more difficult because the absolute value of that buoyancy change is proportional to the amount of air that's expanding/compressing. To put some numbers to it ascending from 33 ft to the surface will make one pound of Bc (air) posative buoyancy expand to two pounds but two will become four, four will become eight and so on. The first represents a change of one pound while the second represents a change of two and the third increases by four pounds. All for the same change in depth. The more air you carry, the greater the buoyancy change with depth. The only thing made easier by overweighting is kneeling. Everything else gets harder.

The reason it's so often said that buoyancy control takes time to develop is because it takes some practice. Unfortunately many students spend most of their class time overweighted on their knees and don't get to practice and are otherwise sabotaged by being overweighted.

If, as you imply, there are DM's that feel the need to be overweighted in order to demonstrate skills, it's an absolute disgrace and probably goes a long toward explaining why so many students have trouble learning this stuff.

 

[Mike Harmon]

A day or two ago someone mentioned a factor that I hadn't even thought of. When I bought fins, I got the Scubapro Twin Jet fins because 1) they were the only yellow fins the shop had, and 2) they were positively buoyant. I guess the thing going through my mind was that I was going to break a strap or something and see my high $$$ fins heading for Davy's locker. I never even gave a thought to the fact that they would make me a little bit "light-footed". Yes, I know, that's a lame excuse, but it may be a minor factor nonetheless.

Regarding the lead to body weight ratio, I guess I should mention that I'm 6'2" and weigh about 280. I'm not the Pillsbury doughboy, but I'm far from "lean". The instructor started me with 18 pounds of weights on a belt. I was in a jacket BCD and a shorty suit, and I could float at eye level with an empty BCD and full lungs. To sink to the bottom, I had to completely exhale all the air in my lungs. As soon as I inhaled any amount of breath at all, I started floating back up. While I was on the bottom on 9+ feet of water, the DM kept trying to get me to add a little air to the BCD to do the fin pivots, but as soon as I gave the inflater just a tiny tap of air, up I went, without even inhaling. I felt like the guys you see in the space station videos. By the time the pool sessions were over, I felt like I was starting to get the hang of it, but by then, it was time to get out.

I'll talk to the instructor before I get back in the pool and discuss the weight thing with him. I know I have a breath control problem, but I feel like there is another factor out there that isn't being dealt with. Yes, I know I need to lose some of the fat, and I'm working on that. However the DM had more than me, and he seemed to be doing OK. Maybe he had some lead in his trim pockets.

Any comments?
Mike

 

[MikeFerrara]

"proper weighting" can be defined as being neutral with a near empty tank.

If we can assume that floating at eye level while holding a normal breath is neutral (and I'm not really convinced that it is) then you need to do that test with a near empty tank OR add an amount of weight equal to the weight of the air that you cary (about 6 pounds for an 80 cu ft tank). Being underweighted isn't any better than being overweighted. To make this a better test, after getting "neutral" on the surface, make sure that you can comfortable descend a bit and hold your depth.

 

[MatWill]

mikeferrara you sound so jaded...

the reality of the situation is that not everyone going through there OW course is a potential Navy Seal. you need to accommodate the ability to teach all types of students with the necessity of teaching them properly. maybe your just PADI bashing under your breath, but until the system changes you have to work with what your given, thats why DM's assisting a PADI instructor will say .. add more weight! it helps the class over all... are people better divers for taking this road? maybe so and maybe not.. as long as they know the fundamentals of what they are doing they have a chance.. and most learning is self learning and its what the students take away with them that matters most imo.

buoyancy is a personal thing.. guides like buoyancy checks help people work out there personal buoyancy. if you have another way to do it.. feel free to tell people how you do it.. and let people make up there own minds. as long as they get there in the end its all good in my book.

remember diving is meant to be fun.. to call in the fire and brimstone because something doesnt go your way just shows that you maybe should have quit the diving industry awhile ago.