Helpful Training Hints
A proper ascent requires that you should be looking up to see what you're going to avoid hitting...right? If you're looking up, where is the open end of the snorkel pointed? .......Down. As your looking up, tilt your head way back. Puff a small amount of air into the snorkel as you begin the ascent. As you approach the surface, exhale through the snorkel untill you break the surface and have tilted your face down. Guess what? The water will be gone! It's a good idea to place your tongue to the roof of your mouth while slowly inhaling the first breathe.
The procedure for regulator clearing is pretty simple. Take the regulator out of your mouth, blow a tiny stream of bubbles, put it back into your mouth and either blow or press the purge button. There is another way called the swishing method. You simply wiggle your lower jaw back and forth and the regulator will clear. Folks who tense up during regulator clearing do so not because of the procedure, but rather from the fear of being without air. If you see someone do a really quick out and back in, usually followed by a huge burst of air as they slam the purge button down, then they likely have no confidence that they won't be out of air. I empathize for anyone who feels this way. However, this degree of nervousness can come back and haunt a diver years later. Regulators get knocked out of our mouths on occasion, and a person who immediately panics will get into serious trouble.
Practice regulator clearing again and again and each time take just a little longer to put the regulator back in your mouth. Keep at it until you can take 30 seconds and not get excited, then work up to your best level, but 30 seconds is minimum.
Most people who have trouble with mask clearing exercises are either dedicated nose breathers or they are leaning their heads back when they remove the mask. The second problem is real easy to fix, just don't tilt your head back and water won't run up your nose. The first group however is going to have a slightly rougher time of it.
This is the procedure that I have my students use when they have problems with mask clearing. Start in shallow water with your snorkel, fins and boots. You won't need your mask. Bend over placeing your face in the water. If your immediate reaction is to jerk your head out of the water, then you are probably going to have some trouble with mask clearing.
What is likely happening is that when you inhale, you still have a tendency to try and inhale through your nose. This may be just enough to cause some water to be sucked into your nose (a really uncomfortable situation). It may take some tenacity to overcome this speedbump. Don't give up! Keep dunking your face until you can breath through the snorkel without sucking in water. Concentrate on breathing through your mouth. If you feel some water in your nose, just make a small exhalation out your nose. Once your comfortable with that (or at least can tolerate it) try swimming around using the snorkel with no mask.
Once a person can easily tolerate having their face exposed to water while continuing to breath, mask clearing gets really simple. Another problem I have seen is when a person is actually trying to blow the water out, but instead of breathing through their nose, they blow all the air out of their mouth. The net result is a lot of blowing and the mask stays flooded!
The quickest cure is to press the top of your tongue against the roof of your mouth during this phase of the mask clearing. Take a deep breath beforehand and blow, down goes the water. Practice this a few times on the surface.
The final problem that can be encountered is when the air leaks out of the top or side of the mask instead of out the bottom or purge. Try pressing in on the top corners of the mask while clearing. Be sure NOT to pull the lower part of the mask away from your face (pretend that you have no thumbs). If air still blows out other places, then get another mask.
The dearly departed Archamedies was a Greek scientist who described the rules surrounding buoyancy. In a nut shell, Archamedies said that if you drop an object into a liquid, that object would be lifted up by a force equal to the mass of the liquid it displaces.
There is another person whose work has a bearing on buoyancy and his name was Robert Boyle. Robert Boyle discovered that there was a relationship between pressure and volume in gases, like air. Boyle's Law states that there is an inverse proportional relationship between the volume of gas and the pressure. If we double the pressure on a gas, then the volume of that gas will be halved. If the pressure is tripled, then the volume is a third and so on. So for every 33 feet of salt water or 1 atmosphere of pressure that we descend in, the volume of gas will by reduced that factor. At 3 atmospheres or 66 feet (33=1 + 33=1 + 1 for the pressure of air) = 3, the volume will be 1/3
This means that air which we put into a BC will decrease in volume as we descend which in turn causes us to be less buoyant! The reverse is also true when we ascend the air will increase in volume and our buoyancy will increase.
Ideally then the best situation is where a person can dive with little or no air in the BC and thereby keep buoyancy shifts to a minimum. This is achieved when a person has the minimum amount of weight on to be able to submerge and stay submerged. However, the problem is complicated by some other factors which must be considered.
If we look at a diver we see that besides the air in the BC we also have three other items which either change volume or change in weight. The diver themselves change in volume with each breath cycle. As they inhale, they become more buoyant and as they exhale, less buoyant. If the diver is wearing a wet suit, it will compress under pressure and as the diver descends they will need to add air to the BC to stay neutral.
The third item of consideration is the air cylinder or tank. Although most people never think about it, air has weight. In fact 80 cubic feet of air weighs around six pounds. With many Aluminum cylinders, this means that the cylinder can become buoyant when enough air has been used. Typically, this occurs around 800 PSI with many Aluminum 80's.
OK, so lets review all this for a second. We start with a diver on the surface wearing a wet suit. This requires that the diver has to wear weights to overcome the additional buoyancy of the suit. The diver lets all the air out of the BC to descend, but has to keep adding it back as the suit compresses and as the air in the BC compresses. The diver has to add enough air to become neutral, but this shifts as the diver breathes plus the diver will have to compensate for the loss weight of the air in the cylinder during the course of a dive. Yup, that's about right!
To find out what your minimum weight requirement is will require a pool,
the services of a friend and a variety of weights.
Start by entering the water with full scuba gear but no wet suit.
I prefer you have no more than 1000 PSI in the tank. This will allow you to
be able to easilly make a 15 feet safety stop in the real world.
Have your friend at the edge of the pool at the deep end. While floating, deflate
your BC fully (remember to have the regulator in your mouth). Remain motionless
and note how high you float. Some people will sink even with no weights.
If this is the case, then you are through with this part of the weighting
procedure. If not, then lets go on.
Have your friend hand you weights in small increments until you can descend. Test the amount of weight by removing a pound and trying again. You are looking for the amount of weight that will make you neutral and since your not wearing a wet suit and all the air is out of your vest, you should remain neutral at all depths with only your breathing affecting buoyancy.
If things look right, put the weight on a belt and try it again. The acid test is whether you can float motionless and rise and fall with each breath. If you immediately sink when you stop swimming, you’re too heavy. Conversely, if you float up when you stop swimming, you're a tad too light.
Once you have this done, make a notation in your log book. Write down the amount of weight and note what size cylinder you were using.
If you use a wet suit you will need to repeat this process with all the configurations that you wear. For example bottoms only, top only, full suit, full suit with hood, etc. There is however a procedural change in weighting when wearing a wet suit.
When you had nothing on but your bathing suit and gear, you weighted yourself to become neutral at the surface. With a wet suit, you may want to weight yourself so that you become neutral at a depth below surface. This has a safety advantage in that you will be positive at all times while on the surface.
Some instructors advocate weighting for a ten foot neutral. This means that you have to make a surface dive to ten feet at which point you will be neutral. I personally do not like this because I consider it a hazard, especially on boat dives where you might find yourself making an un-controlled ascent into the bottom of a boat. Instead, I prefer to weight where I become neutral a foot or two below the surface.
To do this enter the pool again with whatever combination of wet suit you wear. Weight yourself so that you float at mid breath with the water level at the upper half of your mask. Now to test this weight do a feet first surface dive.
A feet first surface dive is done by starting with your legs together and hands at your side. Rapidly spread your legs and raise your arms like you were doing a jumping jack. While doing this exhale sharply. The combination of these should place you several feet below the surface in a vertical position.
What happens is that the suit will compress and if the weighting is right, you will stay right there where you can roll horizontal and make a swimming descent to the bottom. If you're too light, you will simply float back to the surface with your head poking out a few inches. Add a pound or two and try again
This procedure seems to give a few people problems but it's worth practicing until you get it right. The main problems come from people not exhaling or from kicking which will put you right back on the surface. Another area which causes problems is when you fail to get all of the air out of the BC. You may have to tilt yourself slightly in the water to get all the air to the exhaust valve. Once you get the hang of it however, this makes every descent controlled from the surface down.
When you find the correct combination of weight, write it down in your log book along side the configuration of the wet suit.