Buoyancy 1.0 - the sudden fly away effect

[MeetTheFishes]

I'm brand new to diving. I've completed OW cert dives 1-3 and am doing 4 this weekend.

I have negligible buoyancy control, of course, but dive 3 went much better than dive 1 so I'm at least on a path. I noticed by dive 3 that I could avoid bumping along the bottom with some breathing/BC balancing and stay a foot off the bottom for a while, but sometimes, without touching my BC, would start to drift up above my teacher and have to dump a ton of air to get back down. On another thread I saw the phrase "I tend to pop out of the zone by taking in too deep of a breath". Is that likely what's going on? Is my breath depth able to take me from happily swimming near the bottom to rocketing to the top?

If it matters, I'm diving in Seattle so it's a 7 mm dry suit and 29 lb of weight. TIA.

 

[Insta-Gator]

Sounds like you may be carrying too much weight. A proper weight check with your tank at about 500 PSI will help. Don't think about it too much, you'll get stressed and tense, which ruins buoyancy control.

If you are offended by anything in this post, then my efforts have been rewarded. Tapatalk+Autocorrect

 

[krawlings]

Like Insta-gator said It sounds like you are over weighted and need to do a proper weight check . You should all so keep in mind that when you are over weighted the depth changes can be exaggerated . Remember to make very small air adjustments and wait for the adjustment to manifest . and with you breathing make sure to keep it in a normal rhythm and as you get more experience in diving you will get to know how your body feels when rising and falling and be able to catch it before it gets to out of control. with new divers, they are a little tense and take deep breaths and breathe faster witch can effect your buoyancy. good luck and enjoy

 

[MeraSonnet]

Congratulations on your pending certification! Once you get certified, you can add an excellent additional training session called Peak Performance Buoyancy (a PADI additional course). You work with your Instructor before and then during a dive to explore all the factors affecting your buoyancy control. They cover proper weighting, so you can initiate figuring that out no matter how you are garbed and geared and what the dive conditions are (different weight of course for cold water with more gear, compared to tropical water diving with a bathing suit and basic gear). Then under water, your instructor and you spend more time focused on getting your fin pivot down... and this skill will become over time something you do very naturally first thing as soon as you complete your descents. It is nice to focus more on this topic all by itself, on another day and another dive, because there is a lot going on in getting through the certification dives without trying to perfect this aspect. Did this training myself with a dedicated intructor on about the 3rd or 4th ocean dive after certification, and man did it help.

 

[TSandM]

If you think about it, neutral buoyancy is a tenuous state of affairs. It requires that the lift you get from the things that contain air -- whether that's your lungs, your wetsuit, or your BC -- precisely balances the tendency of the rest of your gear to sink. Since the air in your BC and wetsuit is constantly changing volume as you change depth, and your lungs are changing volume as you breathe, you can see that perfect neutral buoyancy is a very fragile thing, and nobody achieves it. We all cycle between positive and negative, and as long as we do so in a rhythm that results in no net change in depth, we are happy that we are neutral.

So, if you have achieved a relatively neutral state, you ought to stay just where you are, right? In order to lose the stability you have, something has to change -- you have to add air to something, or air in something has to expand (which it won't do if you stay at the same depth) or you have to apply an outside force that pushes you upward. Two of those things are pretty possible. The biggest one I see in new divers here is that you probably aren't anywhere near horizontal in the water. If your feet are below you, then when you kick, you are driving yourself upwards. In order NOT to float away, you have to keep yourself negative all the time, which means that if you stop kicking, you will sink. If you add air to your
BC to try to stop sinking, then the minute you begin swimming again, you will rise in the water column -- and when you do THAT, the air in your BC and thick wetsuit expands, and tends to make the rising go even faster, and continue even if you stop kicking, until you vent air to make yourself neutral or negative again. The solution to this particular problem is to try to get in a horizontal posture, and that will be very difficult if all your weights are in your BC weight pockets and a belt. Weight down around your waist is usually below your center of gravity, so packing a whole bunch down there will make you want to float feet-down and head up. If your BC has trim pockets, you may be able to move some of your weight up there, and that will help.

Total weighting is also very important, because the more air you have to put in the BC, the bigger the proportional changes in volume with depth changes. Being overweighted doesn't preclude getting neutral -- technical divers dive grossly "overweighted" (very negative) because of the large volumes of gas they take with them. But it complicates precise buoyancy control, because you have to stop any excursion from your desired depth very quickly, since the gas expansion in the BC will cause your rise to accelerate fast. 39 pounds is a lot of weight for someone in a wetsuit. Our students wear 7 mil suits with 7 mil core warmers, and generally need somewhere in the 25 to 30 lb range for ballast, with a jacket BC and steel tank. If you are diving aluminum, you will need about five pounds more than that, and if you are very tall or very large, you will need more weight. So 39 pounds, although on the higher end of the range, is not inconceivable -- but a formal weight check would be an awfully good idea.

Finally, breathing pattern is important. We used to do an exercise in confined water called the "fin pivot", and although it wasn't one of my favorite drills, it did help the student who mastered it understand how breathing rhythm is important. As you inhale, you WILL begin to rise -- but you have inertia, and the water has resistance, so it doesn't happen immediately. If you exhale before you have really begun to move upwards, you will arrest that tendency, and move back through neutral to negative. Inhaling before you have actually sunk will cycle you back through neutral -- and so on. Obviously, if your breathing pattern changes, your buoyancy will change. One of the things that is VERY common in students is that, when they are asked to do anything other than simply survive and swim, they will either sink or float up. That's because they change their breathing (and often try to hold their breath) when they concentrate. You can try an experiment at home. Sit and breathe quietly, and then pick up something and begin to do something complicated with it -- open a tight jar, or thread a complicated strap. I can guarantee you your breathing will change! And it does this underwater, as well. If you begin to breathe rapidly and shallowly because you are stressed with a task, you will be holding a larger volume in your lungs, and you will begin to float up.

It takes time to master all this stuff. Buoyancy in Puget Sound is much more challenging than buoyancy in a 3 mil wetsuit in the tropics. But the good news is that it can be learned, and there are a lot of folks around who enjoy working with new divers and helping them get on top of this kind of thing. Once you are certified, you might want to take a look at our little local forum, nwdiveclub.com. There are standing dives most weeknights at various places, and it's also a great place to look for a buddy for a weekend dive. A lot of us like beginners -- they still think starfish are wonderful!

 

[seattlepaul1975]

@TSandM.....You mean starfish are not wonderful. Damn! Guess my newbie stripes are showing.

I have fought with buoyancy my entire dives so far..I have been getting better but carry a bunch of weight....last dive was 45lb. Yes I know a TON! But I finally felt heavy. All dives before I had AL tanks not Steel. This last dive I had steel. When I had the AL's I would pop to the top at 1k and just couldn't stay down. With the steels and the heavy weight I was finally able not to pop to the top. Now I just have to get the balance down right. When I am back from Thailand I will be getting my own gear and saying goodbye to the weight belt So I am sure that will just put me back at almost zero on trying to get the buoyancy right.

Yes I was also in a dry suit.

 

[DevonDiver]

...am doing 4 this weekend....I have negligible buoyancy control,...

Basic buoyancy control 'should' be mastered before you leave the confined water portion of your Open Water course. If you feel that your control is negligible then I believe you are well within your rights to raise this concern with your instructor. You should not be progressing into open water dives without reliable buoyancy control. You should definitely not accept yourself to be certified as a diver without this skill competency.

It has become regrettably 'standard' in the scuba industry to progress divers through a set-duration and/or dive-count training program without sufficient attention paid to the actual skill development that those divers accomplish within those strict training parameters.

The Open Water course is a minimum of 5x confined water sessions and 4x open water dives. That minimum reflects the least training that a diver should be given... not the most training. Not every diver masters the syllabus within the constraints of those minimum requirements. In reality, most need more. Some need substantially more.

Sadly, the pressures of instructor/center profitability have become so prevalent in the scuba industry that individuals are rarely given the opportunity, or advice, to undertake further training to achieve the necessary results. It's easier...and more profitable... for instructors to lower their standards and simply 'sign off' certifications for struggling student divers.

My advice is to not accept that situation.

If you need to ask these questions on a public internet forum...whilst still actively engaged in your training course...then your training may be falling short in providing you with the skills and knowledge that you'd otherwise expect to have paid to receive...

....dump a ton of air to get back down.

As others have mentioned, this "phenomenon" tends to occur when you are over-weighted. A surplus of weight carried needs to be off-set by adding more air into your BCD. This is necessary to create neutral buoyancy at a given depth. However, when you ascend that larger volume of air is subject to expansion. Thus - more weight equals more air equals more expansion.

The greater the volume of air in your BCD expands, the more drastic the shift in your buoyancy will be, over a given distance ascent. A large volume of air, expanding on ascent can easily become uncontrollable. This is especially true in shallower depths, where volume of air will double when ascending from 10m/32ft to the surface. In some cases, very excessive over-weighting can actually cause the speed of air expansion to exceed the capacity of the diver/BCD exhaust to dump it - an unrecoverable situation - presenting dangers of lung injury or DCS on fast, uncontrolled ascent from depth.

You are supposed to conduct weight checks at the outset of each open water training dive (and during your confined water session also). The aim of these is to teach you how to conduct the weight check...and also to help refine your accurate weighting requirements as the course progresses. This has the effect of reducing/eliminating the issue of over-weighting as the course progresses.

Sadly, many instructors seem to deliberately opt for a strategy of over-weighting their student divers. This helps them control the diver/s when in static positions conducting skills. To be frank, it is a lazy instructional habit. Heavy students can dump their BCDs and kneel immobile on the floor when repeating drills and skills. That makes the instructor's job easier - at a significant expense to the student's comfort and long term diving development.

My advice on this matter - whether prompted to or not by the instructor, is to conduct your own personal weight checks at the beginning of each dive (as you should have been taught to). Refine your weighting in line with those checks. This will make your buoyancy control easier - reducing how drastic the effect of air-expansion is for a given distance of ascent and reducing the possibility of a 'runaway' ascent.

For more info on buoyancy issues, you may wish to read the article series I wrote: Buoyancy Masterclass (series of 9)

 

[TSandM]

Andy's right -- in the best possible world, nobody would go to open water dives without having their buoyancy pretty much dialed in. The problem with Puget Sound diving is that most pool work is done in a bathing suit, or maybe a thin wetsuit; almost no one gets to dive the exposure protection they will use in open water in the pool. We can go on at length about whether it is desirable to do that, and why it isn't done, but the fact is that it is not. Virtually all students have to cope with the transition to very thick neoprene (or a dry suit) when they move to open water, with the concomitant massive increase in required ballast. It is not an easy transition. Some students handle it better than others. The skills CAN be learned, but some of us take longer to get that done.

To the OP -- Please read the journal of my open water class that is linked in my sig line. You are not the only person to have struggled with these problems. You are ahead of the curve, because you have recognized the issue and you are thinking about it. We have given you some ideas for how to proceed. You may not get this nailed in your open water dives, but there are plenty of us around to help you with this after your class is over.

Please do not let the comments of anyone who does not teach or dive in Puget Sound make you feel inadequate or guilty about not having mastered this in your first three dives.

 

[tyesai]

One other thing I've noticed in my limited experience about people that just "fly away" is that quite often they are still fining while dumping air. Much of the time people aren't completely neutral and are fining to one extent or another to keep their place in the water column. Then it seems they loose that sweet spot, start to rise, take a vertical position and keep fining while dumping air but they can't seem to dump it fast enough to counteract their slight kicking and the expansion. But, as soon as a divemaster or a buddy grabs their fins they almost immediately start to sink because it stops that reflexive kicking motion. Just something I've noticed...

 

[seattlepaul1975]

Andy's right -- in the best possible world, nobody would go to open water dives without having their buoyancy pretty much dialed in. The problem with Puget Sound diving is that most pool work is done in a bathing suit, or maybe a thin wetsuit; almost no one gets to dive the exposure protection they will use in open water in the pool. We can go on at length about whether it is desirable to do that, and why it isn't done, but the fact is that it is not. Virtually all students have to cope with the transition to very thick neoprene (or a dry suit) when they move to open water, with the concomitant massive increase in required ballast. It is not an easy transition. Some students handle it better than others. The skills CAN be learned, but some of us take longer to get that done.

To the OP -- Please read the journal of my open water class that is linked in my sig line. You are not the only person to have struggled with these problems. You are ahead of the curve, because you have recognized the issue and you are thinking about it. We have given you some ideas for how to proceed. You may not get this nailed in your open water dives, but there are plenty of us around to help you with this after your class is over.

Please do not let the comments of anyone who does not teach or dive in Puget Sound make you feel inadequate or guilty about not having mastered this in your first three dives.

Totally agree....going from the pool in a shortie to the drysuit even in the pool than drysuit in the openwater is a huge change. I was lucky that I was able to do 3 dry suit pool days. Just when I thought I had it understood with a BC, the dry suit is added and a whole new set of variables was added with different air levels and more "pockets" for air to be in. I feel ok doing it now in the open water dives....not perfect, but I do not pop to the top like I would in the pool and can stay fairly level and at a constant depth. Just takes time and practice....guess that is a good excuse to DIVE DIVE DIVE!