Maintaining depth in blue water

[richboslice]

I have been really trying to nail my navigation skills by holding a heading through blue water with a soft bottom to reach a part of the quarry we dive in. I have been having a lot of trouble keeping a depth. I slowly start to descend. Because my buddy wanted to stay above the thermacline, we were trying to keep the dive around 15 feet. I was afraid to add too much to my bc and have to try to let air out while watching my compass. I can usually alter my bouyancy by my breathing but without a visual reference it is difficult to do this. By the time my depth gauge registers a change I'm already to far to change it with breath alone. How do you guys keep a steady depth? One thing I have done different is, I added some trim weight pouches to the shoulder straps on my bc to help me float more horizontal. Not sure but I think this may be causing me to swim differently now

 

[NorCalDM]

You may be overweighted I would drop two pounds and see what that does for you. Always make weight changes in small amounts and I always log what weight I use and how it feels so I have a reference. I try to weight myself so I have little to no air in my wing only adding a small amount of air to offset the compression of my wetsuit. Do a few dives to just dial in your weighting the biggest issue I see in newer divers and their buoyancy is they are overweighted and continue to add or subtract air to their bc or they are constantly finning to hold their position in the water colum. When you are able to dive with little to no air in your bc you will be surprised how much easier and relaxed your dives will become. Just my two cents.

 

[KevinNM]

I'm a bit confused. Your computer should show a depth change at a foot or 10cm, at least using my Sunnto or shearwater computers. Though the computer is a bit delayed in showing your depth it won't really be that far delayed. If you are sinking you should see it show up on your computer at no more than 2 feet, which is normally within the range of what you can correct with breathing. If you change it to metric you'll see it show a depth change at about 4 inches instead of 12 inches, which I find helpful.

However if you are normally sinking what that typically shows is that you are actually not neutral, you are negatively buoyant and are maintaining your depth by breathing deeply. When you get task loaded with navigation you start breathing normally and, being negatively buoyant, you sink.
I'd suggest you consider adding just a bit of air to your bcd and get actually neutral before starting the navigation exercise.

You can sometimes also get some idea of whether you are sinking or rising by looking at the tiny particles in the water. These are normally pretty much almost suspended, so if they appear to be rising it is probably you that is sinking. If you are in crystal clear water then that won't work.

 

[Diving Dubai]

This article is posted without permission, but I'm sure Gareth wouldn't mind. This migh t help you to understand your buoyancy issues, as more o fan explanation to the other great information posted above

Blog article and other great one's here

From the blog post "Fine tuning buoyancy"

"Let’s start with a generalisation. Everyone dives negatively buoyant.

OK, now in fairness, obviously the above is not true. Obviously there are plenty of people who dive neutrally buoyant. It’s just I don’t ever get to meet them. The people that come to me invariably have buoyancy control issues, and invariably they are negatively buoyant.

Firstly, how do I know this is the case. How do I know that someone is negatively buoyant. Put them on a platform and they appear to be hovering over it without moving up or down. Are they neutrally buoyant? Not necessarily by what is admittedly my own definition. Look at the following image:

Think about this image as your breathing pattern. At the top is a completed inhalation. At the bottom is a completed exhalation. It’s nice and regular, isn’t it. Nice, slow, full breathing. This will ensure your lungs are working at maximum efficiency, and minimise carbon dioxide buildup. Well done you.

So where does buoyancy control come in?

My definition of neutrally buoyant is this; a diver that it totally stationary in the water column when they are half way through their breathing pattern. They will ascend if they take a full breathe in and hold it. They will descend if they completely exhale, and hold it. And here in lies the problem.

A considerable number of divers do not know this, and thus do not strive for it. Take a typical situation of a diver descending down a shotline. As they approach the bottom, they see a wreck emerge out of the gloom. It’s becoming unfashionable to just slam into it, so they try to avoid doing so. They inject a huge amount of gas into their BCD. However, our UK waters are not condusive to adequate preparation, and we often do not have enough time to inject an appropriate amount of gas. Equally, people are afraid of putting too much gas in their BCD. So what do they do? To stop them from hitting the wreck they take a massive lungful of gas and hold it in. They then hover motionless above the wreck. They are, I repeat, not neutrally buoyant at this point. This is also demonstrated nicely by some new CCR divers, who have often developed this habit whilst diving OC, and nose dive into the bottom the first few times they descend because of course the gas volume, and thus the buoyancy is not changing with their breathing.

Nothing wrong with this in OC diving, as long as the next thing that happens is an adjustment. They need to adjust their buoyancy devices so that they are once again neutrally buoyant in the middle of their breathing pattern. Unfortunately, this is rarely done for a couple of reasons. Firstly, people are fairly task loaded at this point. They have the wreck in front of them, they have to get their bearings, find their buddy, get swimming etc. They are distracted by looking at things.

What happens is they end up breathing in the top half of their breathing pattern, the top half of their lungs. This is a very inefficient way to breathe. The brain is quite remarkable in that it puts a mental filter in place, and people just breathe consciously in the top half of their lungs. It takes very little capacity to do this. It does, however, take some capacity.

When that person forgets to breathe in this manner, they breathe out past the half way point and obviously become negatively buoyant. This can be seen in people who every now and again place a hand, or even just a finger, against the wreck. They haven’t suddenly been pushed down. They are just very slightly negatively buoyant. Watch for it in yourself and other divers, you might be surprised. With some divers it might be an aggressive hand placed on the wreck to push them back up. With others it might just be a finger tapping against it every minute or so as they drift down. The underlying problem is the same in both cases.

You also see this in divers who appear to be neutrally buoyant, but immediately descend once they are given something else to do, such as put up an SMB. All that has happened is that they no longer have the spare capacity to remember to breathe in a specific way. Their autonomous systems take over the job of breathing, they breathe out, and down they go.

The example I gave above of an initial descent followed by a failure to adjust properly is just part of the issue. The same occurs when a diver is required to change depth during the dive when, for example, swimming over part of a wreck. They make an adjustment with their BCD or wing which takes care of the macro change, but they do not finely adjust it. They then unconsciously remain neutrally buoyant by adjusting their breathing.

There is also a mental game I see in a lot of diving. It is very comforting to many divers to remain slightly negatively buoyant. At the top of their breathing pattern they are perfectly neutral, and at the bottom they are slightly negative, which means they are not going to rocket to the surface. Many people find this very comforting. This is demonstrated nicely by forcing people to become neutrally buoyant, and they usually report a feeling of “lightness” or a worry that they were actually drifting up to the surface. This is very common on fundamentals, and it is usually only the video that proves to people that they were actually just hovering in place rather than rising uncontrollably to the surface.

It is far less frequent, but the opposite is also true – some divers keep themselves slightly positively buoyant. As I said, this is far more rare, but I have seen it. In this scenario a diver will have typically ascended part of the way up a wreck, and will then swim along at the same depth by breathing in the lower half of their lungs. Again, once they are distracted by something and conscious control of their breathing pattern is lost, they usually end up rising and having to make a macro adjustment with their BCD or wing.

Without reiterating all the other articles that I have written, and remembering the caveat at the beginning of this article that this might only be of interest to people who want to master buoyancy control, let’s just assume for the sake of politeness that this is a problem and we want to resolve it. In a nutshell, it means that people are having to focus on their breathing rather than the dive, and they risk losing control if they become task loaded. They will also be disturbing whatever it is they are swimming over, and will be using more gas than they need to.



How do we fix the problem?

Well, the first thing we have to do is to get over a historic evil. The lesson “never hold your breath when scuba diving”. This is, of course, a necessary evil for brand new scuba divers, but is a nonsense for experienced divers. the rule is embedded in the materials of training agencies, and is often called the “first” or “golden” rule. From a psychological perspective this rule is a nonsense. Firstly, holding your breathe when neutrally buoyant or descending should not be an issue. Secondly, it reinforces a negative, which educational psychologists have known for decades is a really bad idea.”Never hold your breathe, never hold your breathe, hold your breathe, hold your breathe…." A far more sensible rule would be “always breathe normally when ascending”.

Let’s assume we are going to hold our breathe now and again. Don’t worry, I won’t tell. This gives us the ability to run a little buoyancy test. Relax, and take a few normal breaths. Ensure you are breathing normally – you might actually have to consciously do this. Now, after a few nice slow breaths just let about half the gas out of your lungs and, wait for it, stop breathing. Stop. You need to be fairly ruthless with yourself to let half the gas out. Your instinct will be to let less than half out, which of course helps the issue but does not solve it. Try it again. this time make sure you are not waggling your arms or legs to compensate. Keep still. Freeze, in fact. Once you’ve got an idea of where half way out is take a look at what happens to you when you stop breathing. Do you go up. Bet you don’t. Do you go down? Thought so.

Let’s call this a “micro buoyancy check”. I run this check at the bottom of the shotline, and whenever I change depth during the dive. On the way up, I do it when I come to decompression stops.

Being neutrally buoyant in this manner causes the stress levels to drop quite dramatically, especially at decompression stops where you might have gas switches etc to perform. It means you can initiate descents by simply breathing out and holding it for a second. You can initiate ascents by simply breathing in – although here you really do need to be careful to only hold it until you start moving.

So next time you are floating motionless and think you are perfectly neutrally buoyant, just take a moment and see if you really are.

Dive safe.

 

[MXGratefulDiver]

Maintaining buoyancy control mid-water is a skill that requires practice. The last dive of my AOW class is conducted entirely at 20 feet, even though you will at times be in more than 70 feet of water. The reason I do this is to encourage my students to practice their buoyancy control, particularly while "task loaded" with a skill such as navigation. As such we do several timed navigational patterns. The purpose of the patterns isn't so much navigation as it is training your body what neutral feels like while you're focused on doing something else. Another aspect of the exercise is this ... one dive buddy uses a compass to plot the course, and the other dive buddy uses the dive computer to time each leg and to monitor depth. If the navigator begins to change depth, it's the buddy's responsibility to let him know, using hand signals to indicate that the team needs to move up or down in order to maintain the target depth. The point of this is to teach each diver good buddy positioning and communication.

It's a challenging exercise. Don't expect to do well the first few times you try it ... but I do recommend you try it. Keep it fun and don't let the first few attempts frustrate you. Keep the courses short ... one minute legs are plenty, particularly at first. While you'll probably bollix the first attempt or two, you'll find the learning curve ramps up pretty steeply, and by the fourth or fifth attempt you'll be getting the hang of it. Keep your breathing pattern consistent, play with weighting if it appears you're cycling air through your BCD, and keep the exercise within the 15-20 foot range.

Remember, we hone our skills through repetition. Make a game of it. Do it at safety stop depth, after you've done your safety stop on a normal dive if your dive opportunities are limited. But good buoyancy control takes practice. This is just one way you can get that practice in a way that helps you achieve your stated goal of managing your buoyancy without obvious visual clues. Over the past 12 years, I've found it to be an effective way to train people how to manage that skill.

... Bob (Grateful Diver)

 

[Diver0001]

I have been really trying to nail my navigation skills by holding a heading through blue water with a soft bottom to reach a part of the quarry we dive in. I have been having a lot of trouble keeping a depth. I slowly start to descend. Because my buddy wanted to stay above the thermacline, we were trying to keep the dive around 15 feet. I was afraid to add too much to my bc and have to try to let air out while watching my compass. I can usually alter my bouyancy by my breathing but without a visual reference it is difficult to do this. By the time my depth gauge registers a change I'm already to far to change it with breath alone. How do you guys keep a steady depth? One thing I have done different is, I added some trim weight pouches to the shoulder straps on my bc to help me float more horizontal. Not sure but I think this may be causing me to swim differently now

When under task loading, use chaining.

Task loading for all intents and purposes can be defined as doing more than one thing at once. In your case you're trying to navigate and keep your depth steady at the same time.

Chaining is doing multiple things one at a time by switching back and forth between them. This is kind of like how computers work. Most of them do one thing at a time but switch between tasks. A computer is fast so to us it looks like multitasking but most of the time it isn't.

So how do you apply this?

You need to keep a close eye on your depth or you won't be able to keep it steady without a visual reference. This isn't just true of novice divers, this is true of all divers. So in this case what I would do is to set my direction and kick a few times in that direction and then switch my attention back to my depth again. Get the depth right, switch back to the compass, kick a few times and then switch back to checking depth. etc etc. This constant switching takes some practice before it becomes second nature but you will eventually "automate" it.

To give you an example, I dive on a wreck fairly often that requires us to leave the bottom and swim back to shore mid-water without a reference. Using the technique I just told you I can swim for 20+ minutes through zero reference and my depth doesn't deviate more than 30cm or so from where I wanted it to be at any given time.

That's the basics. The more advanced option you have is to delegate different tasks to different team mates. During the swim I was just talking about, my buddy and I perform different tasks. For example, I will control depth and decompression stops and he controls navigation. We can both do it all but this is just easier. So what he does is look at me to see depth and he uses me as a visual reference to judge how deep he should be and I look at him to see which way I should be swimming. That way we can both give more attention to our designated tasks and it makes the swim more accurate in terms of both depth and direction.

hope that helps.

R..

 

[richboslice]

Thank you very much. I actually asked my buddy to keep depth and stay in my periferal field but that didn't work out. But I noticed I was having a lot of trouble just keeping my depth in itself. Do you control your depth with buoyancy or your finning?

 

[Steve_C]

Sensitivity decreases with depth. If you are task loaded it is easier to hold your depth at 20 ft then 15. That way if you do deviate by a couple feet before correcting it is less significant. I have no trouble with any visual reference but in open water I have to watch the computer. Much easier at 20-25 than at 15 maybe 12.

 

[Jack Hammer]

A couple of things to try. Start with adding just a little air if you are negative, add a little if you are positive. Pay attention to your ears for subtle changes in pressure. Look for particulate in the water, even clear blue water will often have some. Use that as a visual reference to keep depth. Practice. ☺

 

[Steve_C]

Brightness of light is also often an indicator that you are rising.