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Scuba Tank

Aluminum vs. Steel tanks: How Heavy is that SCUBA Tank?

By Jose

What 2 metals are SCUBA tanks made of, Aluminum vs. Steel tanks, How heavy is a SCUBA tank

What kind of tank do you use when you go diving?  The size of the tank and whether it's made out of steel vs. aluminum will hugely influence how much weight you'll need to take with you on your dive.   Many divers think diving with one type of tank is better than diving with another.  The truth is that the type of diving you do, where you are diving and even the thickness and type of exposure protection you use can play a part in your choice of SCUBA cylinder.

In another post, we talked about the importance of buoyancy checks and determining exactly how much weight you need in order to make your body neutral underwater.  Besides your body and your gear, you have to compensate for your SCUBA tank as you dive.

What 2 metals are SCUBA tanks made of?

Aluminum Vs. Steel Tanks

You may be asking ” how heavy is a SCUBA tank,” but the real question is how buoyant it is.  Different tanks have different buoyancy characteristics.  As divers we need to be aware of the buoyancy characteristics of the tanks we use when we dive.  This is important because it determines how much weight we need when we go diving.  It is also good to know because we can use tanks to replace ballast depending on our weighting needs and diving conditions

There are two types of SCUBA tanks for divers to choose from.  Aluminum SCUBA tanks tend to be negatively buoyant at the start of your dive when they are full.  However, as you dive, these tanks tend to become neutral and can even be positively buoyant by the end of your dive. Because of this, you have to consider the tank’s positive buoyancy at the end of your dive when determining how much weight you will need.  

Both steel and aluminum SCUBA tank sizes vary.  Different tank sizes have different buoyancy characteristics.  For example, a steel 120 SCUBA tank will have different buoyancy characteristics than a steel 80 SCUBA tank.  Not only do sizes affect their characteristics, whether it is a high pressure SCUBA tank or a low pressure SCUBA tank makes a difference and so does the tank manufacturer. Faber tanks specs are not the same as Catalina or Luxfer tanks.  It is important to research these differences when choosing your tanks.

Steel SCUBA tanks tend to be negatively buoyant throughout your dive.  So when diving with steel tanks, you will not need the same amount of weight.  It is important to keep in mind that the buoyancy characteristics of steel tanks also change throughout a dive.  So while a steel tank might be very negative at the start of a dive, it can become closer to neutral as you dive.

We did a quick video below to illustrate the point. It’s a cool little experiment you can try with different cylinders and see what the buoyancy characteristics are.

What cylinder do you dive with and why?  Please feel free to comment below, we would love to hear from you!

Scuba Diver removes her mask underwater

Increasing your comfort underwater: One little-known drill that boosts your confidence like crazy!

By Jose

Scuba Diver removes her mask underwater

You’re on a dive in 65 feet (that’s about 30 meters for my non-American friends) and your regulator begins to free flow. What you do next could be the difference between a cools story and a trip to a hyperbaric chamber

 

Without going into what the proper procedure would be (I’ll leave that to the training agencies) how comfortable would do you think you’d be with this situation? Unless it’s something that you feel would be a minor annoyance, you might want to read on to learn a simple drill you could do to help you deal with this potentially dangerous situation.

One of the most important attributes you can have as a diver is to be both comfortable and confident while underwater. Unfortunately, this is one of the toughest things to “teach” in a rushed SCUBA course.  There really are two reasons why this particular situation is hard to teach.  First, most dive courses barely have enough time to cover the basics, much less deal with events like these.  Second, being that this is a situation that is much more about mental state than anything else, it is hard to mimic.

One of the best ways that I have seen my students become comfortable underwater over the years is by mastering skills which require them to hold their breath. The reason why breath-held skills increase your comfort on SCUBA is simple, if you know you can handle tasks which require you not to breathe for more than a few seconds, then any situation which can happen on a SCUBA unit becomes trivial because, for the most part, you’ll always have air when you’re on SCUBA. Even in the event of a worst case scenario, an out of air situation, you’ll still know you have plenty of time to figure out what to do and execute it so you can come out virtually unscathed.

The Skin Diving Bailout

So, just what is a Skin Diving Bailout anyway?  The skill is actually quite simple to complete and does not require SCUBA gear.   This skill should be done in shallow water, 4 or 5 feet (1.5 meters) is plenty.

A skin diving bail out is when you immerse yourself into the water with your mask and fins off. You can wear a weight belt for this skill, just make sure you do a buoyancy check and are properly weighted.

  • You begin by sitting on the edge of the pool with your mask and fins in your hands.
  • You then immerse yourself into the water while holding your breath.
  • Once you are underwater, you place your fins on your feet.
  • Then you put your mask on and clear it,
  • After your mask is clear, you come to the surface and blast your snorkel. You should be able to continue breathing through your snorkel at the end of the skin diving bail out while keeping your head in the water.

The key to mastering this skill is to take your time doing it. Make sure you breathe slowly and deeply before jumping in the water. Take a deep breath just before you jump in the water. 

Now stay calm! Slowly put your fins on, put your mask on, clear it and finally clear your snorkel.    Staying calm and taking your time is key!  You’ll be amazed at how much easier it is to complete this skill when you take your time.  Rushing usually will just make you feel anxious and have you run out of air much sooner.  Be deliberate in your movements.  When it comes to this skill, fast is slow!

This is the real takeaway, whatever happens underwater can be handled.  The key is staying calm, and acting slowly and deliberately.  Watch the video below to see how I do a skin diving bail out.

Have you ever done a skin diving bail before? If so, what was your experience with it? I’d love to know in the comments below.

scuba diver being Neutral underwater

Are you over-weighted too? How much weight do I need for scuba diving?

By Jose

SCUBA diving buoyancy control, How much weight do I need for scuba diving, Dive weightsHow much weight do you use when you go diving?

If you're anything like me when I first started diving it's probably too much!

When I first started SCUBA diving, I did not know I was over-weighted.  It had never really dawned on me to check how much weight I needed.  I was trained with 12 pounds of lead and that is what I dove with.  That is until I got to my Instructor Training Program.  My instructor stripped me down to four pounds and proceeded to tell me that I was diving with way more weight than I would ever need, although he was not so nice about it.  Needless to say, I felt a little silly on that day.  I wish someone would have told me something prior to sitting in a pool with a seasoned instructor trainer…I was red-faced with embarrassment on that day!

How much weight are you taking with you when you dive? Are you sure this is the right amount? If you’re not 100 percent sure that you’re using the correct weight, then you need to read on.

The only way to properly determine how much weight you need in the water is to perform a buoyancy check.  A SCUBA diving buoyancy calculator may be a good idea in theory, but you will only know the right amount of weight by getting in the water and checking yourself.  A buoyancy check is when you place yourself in the water and, through trial and error, find the right amount of weight which you need to SCUBA dive.             

Having the correct amount of weight to act as ballast is super important. If you have too little weight, you will float towards the surface, especially at the end of the dive when your cylinder is lower on gas. If you have too much weight, you will work harder, possibly have your body in a poor position in the water column, and could even place yourself in a potentially dangerous situation.              

The goal of being properly weighted is to end your dive perfectly neutral when you are at your reserve pressure, with little to no air in your BCD.              

If you still need air in your scuba diving buoyancy control device (BCD) when you are at the reserve pressure at the end of the dive you need to ask yourself why? This extra weight simply caused you to exert more energy throughout the entire dive and likely caused your breathing rate to go be higher than it needed to be.               

Before I begin to explain how you can perform a buoyancy check, you have to understand what can affect your buoyancy. 

Some of the things that can affect buoyancy are:

The Density of the Water.

  • Salt water is denser than fresh water. This means you will need more lead in salt water than you will in fresh water.

Your Dive Gear

  • Your regulator, BCD, fins, etc. all have weight associated to them which can affect your buoyancy.
  • Depending on the cylinder you are using, you may need to add weight to offset for the cylinder being low on gas at the end of the dive.
    • This is one of the trickiest factors to consider. The reason why is because a cylinder may be negative and sink at the beginning of the dive, but positive and float at the end of the dive when it is near empty. You have to consider that the compressed gas in the cylinder has weight too. This video below shows you a simple experiment I conducted to illustrate the point.

 


Exposure protection

  • If you are wearing a neoprene wetsuit the neoprene is positively buoyant. Depending on the thickness of the suit and your body size, you will need to offset the buoyancy of the wetsuit.
  • If you are diving with a drysuit, you will also need to offset for the buoyancy created by the drysuit. Depending on what undergarments you are using and the material of the suit itself, you will need to add lead to offset the buoyancy created by the suit and the undergarments.  I would like to mention that drysuit diving should not be attempted without taking a specialty course as it has a large learning curve when compared to diving in a wetsuit

Body composition

  • Muscle is denser than water, so it tends to sink. I have had many students in the past who lifted weights and were very muscular and lean, these students often needed little or no extra weight to stay underwater
  • Fat is less dense than water, so it tends to float. If you have more body fat, you will probably need more lead to offset the positive buoyancy caused by the fat.
  • Lung volume; everybody’s lungs are different. Because we are breathing while underwater, this is the one variable that is constantly changing, however, a bigger lung will have more air in it than a smaller one and hence require a little extra lead.

Because of all of these variables, especially the ones dealing with your body composition. The only way to figure out how much weight you will need when diving is to perform the buoyancy check.

The way I like to perform a buoyancy check is wearing whatever I will be using for exposure protection (i.e. wetsuit or drysuit) and in the same type of water I will be diving in (If you will be diving in the ocean, you need to do this in salt water, the amount of weight you use in a pool will be different than what you might use in the ocean).  

I like doing the buoyancy check for just my body, and then a separate buoyancy check for just the gear. There are two reasons why I like doing it this way.  First, it is easier in my opinion to balance in the water and find the right amount of weight for just yourself.  Second, I tend to dive different gear configurations and different cylinders for different purposes.  By separating the amount of weight I need for myself from the weight I need for my gear, I am able to easily adapt for different cylinders and gear.  If you dive with different gear configurations, you may want to consider doing the same thing.

So how do you perform a buoyancy check? Below are the steps as well as a video showing you how to do a buoyancy check.

  • Step 1: Standing in water that is about neck deep. Take a weight of about 2 pounds (1 kg) and hold it behind your back.
  • Step 2: Focus on your breathing for a moment. Now take a breath that’s about seventy percent of the total volume of air you think you could fill in your lungs (don’t worry too much about an exact amount, it’s probably impossible to determine what exactly 70% is, just use your best judgment)
  • Step 3: Now slowly ease yourself into the water. You want to go really slow to prevent yourself from bobbing up and down if you float.
  • Step 4: Make a note of where you are in respect to the water level and your head.
    •  If you sink, underwater, you will need to try with less weight, or maybe even no weight.
    • If the water level was below your forehead (your eyes as an example) you will need more weight.
    • Repeat this exercise with more weight until you find the correct amount of weight that is needed to be right at forehead level.
  • Step 5:  Once you find the correct amount of weight, make a note of it.  This is how much weight you need to be neutral in the water without scuba equipment on.  If you know how much weight you need for the scuba equipment, and your cylinder at reserve pressure then add these two numbers together and you will know the total weight you need in the water.

 

 

Once I know how much weight I need for myself, it’s now time to do the same for my gear. The gear is actually a bit simpler since there is no balancing required on your part.

The steps to doing a buoyancy check for your gear are as follows:

  • Step 1: Drain your cylinder to its reserve pressure (i.e. 500 PSI or 50 Bar)
  • Step 2: Start with 1 pound (1/2 kilo) and place it in your BCD’s pocket or attach it with a string if your BCD has no pockets.
  • Step 3: Notice if your Scuba Rig sinks of floats. If it floats, add more weight until you can get the rig to be just neutral or ever so slightly negative. If it sinks with no weight added to it whatsoever then you do not need any weight to compensate for your rig’s buoyancy.

 

Putting it all together

Once you know the amount of weight that you need for yourself and the amount of weight that you need for your rig, all that is needed is to add the two numbers together to arrive at how much weight you should be carrying into the water.

Always keep in mind that the number you arrive at will change if you change cylinder types, exposure protection, move from salt to fresh water, or if you gain or lose weight yourself. Also, the amount of weight you arrive at with a buoyancy check is not a number set in stone it is simply a best starting point. Once you start diving, you may notice that you can actually use less weight, or maybe that you’ll need slightly more. If you decide to add or eliminate weight do so very slowly. Your goal should always be to be neutrally buoyant with no air in your BCD at the end of your dive with the cylinder at its reserve pressure.

How much weight are you using when you dive, and what type of exposure protection and rig are you using?  Let me know in the comments below.

Scuba Diving Flutter Kick in Pool

Swimming Like A Fish: How to Master the art of SCUBA Kicks

By Jose

 Scuba Diving Flutter Kick in PoolWhat’s your go to kick when you’re diving?  Why?  Whenever I ask this question, most people don’t really have an answer as to why they use the kick that they do.

Just as important, many times the kicking technique is less than efficient.  In this article, I want to show you the two most common kicks in scuba diving, when to use each one and demonstrate how to perform each kick efficiently.

SCUBA Kicks

The two main kicks used when scuba diving are the flutter kick and the frog kick. The flutter kick is the scissor-like kick which is similar to the kick you would do if you were swimming freestyle. This is the kick most people instinctively do when they first start scuba diving and snorkeling. The frog kick is the kick which resembles the kick used when completing the breast stroke. It’s named the frog kick because it resembles a frog kicking underwater.

These two kicks are go-to kicks used when scuba diving. What many people do not realize is that they have two distinct purposes and should be used accordingly. In the video below I describe the two kicks and when to use each one.

 

Before going into the kicks themselves, it’s important that you understand some general principles that will make any kick you use underwater more efficient.

  • First, you want to make sure you make yourself neutral in the water.  The kick should only be used to move your body horizontally in the water column.  If you are kicking to stay off the bottom, then you are wasting energy.  IN order to be efficient, you must be neutrally buoyant.
  • Second, you need to get used being in a horizontal position. This position will eliminate drag in the water and help you move to where you want to go without wasting energy.
  • Next, you need to understand that your hands are not needed to propel yourself underwater. Your hands should be either by your side, or crossed or someone where near your body where they are not causing drag in the water.  Using your hands to try to move through the water is extremely inefficient
  • Finally, you need to know which kick to use and when.

The Flutter Kick

The flutter kick is a power kick. It is the kick you should use when you need to either move rapidly or move powerfully because of a strong current. Because it is a power kick, it is also the kick which consumes the most amount of gas. This is because the flutter kick has no resting phase. When you are flutter kicking, you are basically constantly moving.

The key to an efficient flutter kick is to keep your feet relatively straight, your toes pointed, your ankles loose and let the power come from your hips. You can see in the video below how I demonstrate this kick.

 

The Frog Kick

The frog kick is the more efficient of the two kicks presented here. It’s the kick you should be doing most of the time.

The frog kick has a built in resting phase. That is to say, once you kick you get to rest and recover while you are gliding forward. Because of this, you’ll consume less gas while diving using a frog kick. The video below describes and shows how to do an efficient frog kick.    

The key to both of these kicks is knowing when to use each one, and to practice them both until you have mastered them. 

One huge help in getting your kicks right is to use an underwater camera to see how you look while you are diving. Many people are surprised to see both what their kicking technique looks like, and what their body position is like. Cameras like the GoPro make it relatively inexpensive to see what you look like in the water.

I’m curious to know, what kick are you using most of the time and why? Let me know in the comments below.

How to Clear Your SCUBA Mask Underwater in One BREATH!

By Jose

clear scuba mask underwater, SCUBA mask clearing tips

How good are you at clearing your mask underwater?  

It might seem like a silly question, but for some people I know, this simple skill is a lot more difficult than it should be.  Mask clearing is one of the most important skills you need to master as a scuba diver. Even though it may not seem like a big deal, the ability to clear your mask is crucial.  In this article we are goig to give you some SCUBA mask clearing tips that will make you a pro in no time!

Something as mundane as a little water in the mask can make you uncomfortable and even anxious. This state can then escalate and make other small issues seem way larger than they really are.   Since you have one uncomfortable situation stacking on top of one another, you can turn an otherwise benign problem into something major.                

Let’s face it, water in the mask is almost inevitable.  A simple smile can force the mask seal to break and let water into your mask. Clearing your mask is super-simple to master, once you understand and practice the techniques.

Before I begin, let me tell you what I consider to be a successful mask clearing.  This may be different from what you are currently doing and it may be part of the reason why you might not be totally comfortable yet with this skill.

When assessing this skill in my classes, a successful mask clearing is when you COMPLETELY clear your mask on LESS than one breath. This means you should be able to do multiple mask clears with one breath. Unfortunately many students I’ve had over the years have taken 2 or even 3 breaths to clear their masks. Having to take more than one breath to clear your mask is extremely inefficient.  

The goal of this post is to help you master mask clearing, so please read on so you can learn more about the tips needed to master this fundamental SCUBA diving skill.  Of course, to fully master this you will have to go practice in the water!

SCUBA mask clearing tips and techniques

There are two basic ways to clear your mask. Below is are descriptions of both methods as well as a couple of videos showing you how to perform them.

The key to effectively clearing your mask is to understand the principles involved and how to position yourself and your mask to make flushing the water out of the mask simple.

Principle number one: Bubbles go up!

Before we get into the technique of mask clearing, it helps to understand how it works. Mask clearing works by trapping air bubbles in our mask. By exhaling through our noses and sealing off the top of our mask, we trap the bubbles inside of our mask. This trapping of the air bubbles also forces water out of the bottom of our masks.

Principle number two: When air displaces water, the water has to have a place to go.

Because we are trapping the air bubbles at the top of our mask, we need to create a gap at the bottom of our mask in order to have a place for the water to go.

Principle number three: Head position matters when clearing your mask.

In order for all of this to work, you have to have you head on a vertical plane. However, this doesn’t mean that your entire body has to be vertical. Simply looking up while maintaining a horizontal body position will do.

So now that you understand the principles, let me walk you through how I teach mask clearing so that you can master it.

  1. First off, I relay to my students that they have to be looking up in order to clear their masks.  You have to make sure that your face is vertical in the water column.  Remember, your whole body should not be vertical, just your face.
  2. Secondly, I tell my students to break the seal of their mask at the bottom, you only need a slight opening here, maybe enough to slide your pinky finger in.  It is common to separate the mask too far from your face which makes it hard to properly clear the mask.  Be mindful of this.
  3. Next I tell my student to exhale slowly from their nose.  For some people it helps to move their tongue to the roof of their mouth to make sure that they are not exhaling simultaneously from their mouth.
  4. As you exhale from your nose you’ll notice the water level slowly going down your face. Once you feel that the mask is clear, continue exhaling slowly and move the mask back against your face top reseal it and stop exhaling. The mask will be clear and sealed!  

See the video below so you can see how I do this skill.


Another way to efficiently clear your mask:

If the above method does not work for you, read below for an alternate method that is also effective.

  1. First, look up, again make sure your face is vertical. and
  2. Exhale slowly through your nose while pressing your hand against the top of your mask to force the top of your mask to seal.
  3. Once you feel the water is cleared from your mask, press the rest of your mask against your face. Your mask will now be clear!

See the video below so you can see how I do the alternate method. The key to making both methods above effective is to EXHALE SLOWLY and ONLY THROUGH YOUR NOSE. Once the water is completely out of your mask, you must adjust the mask to reseal it and stop exhaling.

We hope these SCUBA mask clearing tips have helped you.  Whichever method you choose to clear your SCUBA mask underwater, make sure you practice and master it. You should be able to clear your mask multiple times on a single breath. Doing so will help to increase your confidence and comfort in the water. I can’t emphasize enough how important it is to be totally comfortable with this basic skill.  Not being comfortable with mask clearing can lead to other problems, so be sure to practice, practice, practice!

What method do you use primarily and why? I’d love to know in the comments below.

The Importance of Breathing underwater without a mask

By Jose

scuba diver underwater with no mask

How would you feel if you lost your mask while diving?  How about if your mask strap broke, or your regulator free-flowed, would it just be a minor nuisance or would be a major catastrophe?  

I really hope you answered that it would be a minor nuisance! 

While you can’t “learn” to be comfortable overnight, there are many skills you can practice in the water that will help you feel more comfortable in the event that an uncomfortable situation should arise.

One of the most important things in scuba diving, especially when you are a beginning diver, is being completely comfortable with no mask on while underwater.

Even though it is a really basic skill, knowing that, should your mask fall off, you’ll be totally fine is important. It’s also important to be completely comfortable with the fact that, at some point, the seal on your mask will go and you will need to clear that water from your mask, but that’s another post.

It is very common, especially in the beginning to have some apprehension about water entering your mask, or even losing the mask altogether. The best way to lose the apprehension is to face the concern head on and practice actually taking the mask off underwater while continuing to breathe.

Fortunately, we don’t even need a scuba unit in order to practice this. In fact, if you really wanted to, you could even do this in your bath tub. Granted you’ll look a little silly, and if someone catches you doing this, they might have questions about your sanity, but who cares? It’s all in the name of being a better diver!

In any case, all that is needed in order to become comfortable with breathing without a mask on is a body of water and a mask with a snorkel. The “drill” if you want to call it that, is to turn your mask around and to breathe through the snorkel without pinching your nose. 
See the video below of how I demonstrate this skill

For most, this is a pretty simple skill, however for some, breathing while their face is in the water and nothing covers their nose presents a challenge. The challenge is that many people have been breathing simultaneously through their nose and mouth for all their lives. Because breathing through only your mouth while your face is in the water is not something we normally need to do, it may be challenging. The best way to determine this is to actually do it.

What to do if you have problems only breathing through your nose:

If you happen to be one of the people who breathe through your nose and mouth at the same time, there are a few things you can do to train yourself to only breathe through your mouth so you can be comfortable underwater without a mask on.  These are some of the steps I’ve recommended to students in my open water course who have had this problem over the years:

  1. Start with your mask on backward while breathing through the snorkel and pinching off your nose. Notice how you are breathing. Continue breathing while slowly un-pinching your nose. Do this several times to see if you can successfully breathe through only your mouth.
  2. If the above exercise doesn’t work, focus on where your tongue is in your mouth. Focus on what the muscles in your throat are doing. In order to only breathe through your mouth, your tongue will actually rise a little and your throat muscles will “tighten up a bit” to close off that airway. Because you’ve probably never focused on this, it may be difficult to be aware of this at first, but experiment with moving the back of your tongue towards the back top of your mouth to help close off the airspace from your nose.
  3. Get in the pool or even a bathtub and practice, practice, practice. Like riding a bike, you may not get this skill the first time, but once you do, you will always remember it. This is a fundamental skill in scuba diving that, once you mastered, will help you with your comfort and confidence.

I’m curious to know, did you practice breathing with no mask on when you did your scuba diver course?  How easy or hard is this skill for you? Let me know in the comments below.