Motor skill tips for diving students

Motor Skills – Tips and Advice

Diving students can be overwhelmed by the number of complex motor skills that they need to learn and develop as they progress through the Open Water course and gain experience as certified divers. It takes time and practice to get the hang of it.

One way to learn is to break down a complex series of actions into their individual components, then think it through and visualize yourself performing each discrete step. As you practice in your mind, gradually increase your speed until you achieve a fluid motion.

Mask Clearing

There are four discrete steps to take to clear water out of a flooded mask. With practice, these will all flow together.

  1. Look upwards to pool the water at the bottom of the mask.
  2. Press your fingers against the top rim of the mask to hold the seal against your forehead.
  3. Inhale deeply through your regulator.
  4. Exhale with gentle force out your nose.

Repeat as many times as necessary.

To visualize this process, imagine that you're blowing your nose into a kleenex tissue.  When you blow your nose, you position your fingers to press against your cheek bones. So when clearing a mask, imagine you're blowing your nose…. but press your fingers against your eyebrows.

What happens when you perform this skill is that when you exhale out your nose, the increased air pressure inside the mask will break the seal against your skin just above your mouth and the air pressure will force the water out the bottom of the mask where the seal has been broken. Too easy!

Proper Finning

All your underwater propulsion comes from the action of finning. It's a waste of energy and tank air to use your arms for propulsion. Proper, effective and efficient finning techniques take time and practice to develop. Many new divers become fatigued by water resistance against their fins as they swim around. To avoid thigh muscle burn, many novices take a shortcut and swim like they’re riding a bicycle or climbing a ladder. Of course they need to kick at twice the speed to make any forward progress, so this finning technique is very inefficient.

Most 40 minute dives cover a distance of 500m or less. Some of this bottom time will be spent hovering in one spot, some time swimming slowly and some time swimming faster between points of interest. Different finning techniques can be used in each situation.

For faster swimming speeds, the thrust comes from your hips and thighs. To visualize how this works, lie down on the floor on your back and put a pillow under your knees, to keep your legs somewhat bent. Imagine that the ceiling above you is actually the seabed below you. Now raise and lower alternating legs…left up, right down, left down, right up. Notice that the upward thrust is from your hips and thighs. The action is very much like walking. Now, as the upward thrust approaches its maximum point, use your calf muscle to whip your foot and straighten your leg. Of course, you are doing this on the floor at home facing the ceiling. In the water, facing the bottom, the thrust is on the down-kick. Visualize in your mind that your fin tips are like palm trees swaying in the breeze. Propulsion is best when you follow through and not cut the fin-kick cycle short.  With split fins, higher speeds are achieved with a faster, narrower kick cycle . With conventional fins, higher speeds are achieved with a more powerful kick stroke. Consequently, stronger swimmers tend to perform better with conventional fins, while weaker swimmers tend to perform better with split fins.

For slower swimming speeds, for example when you’re scoping out a small area, thrust comes mainly from your calf muscles, or below your knees, because you don’t need the full energy that comes from your hips and thighs. To visualize this, lie down on the floor face down. Bend one leg up from the knee. The thrust force comes in the action of straightening your leg…the downward thrust. While one leg is thrusting downward, the other leg is bending upward. In reality, there will be some thrust that comes from your thighs, but most of it will come from your calves.

When ascending vertically straight up, like at the end of a dive, keep your legs straight and your toes pointed downward, thrusting from the hips.

One of the most common problems during a dive is a muscle cramp in your calves. Stretch out the muscle by taking a firm hold of your fin tip and pulling it toward you until the cramp subsides. Better yet, give your buddy the “problem” and “cramp” signals, point to your leg and have them help you. Be mindful not to lose neutral buoyancy while you’re doing this. Sometimes it’s safest to drop to the bottom and stretch out the muscle there, or hold on to a rock face on a wall dive.

It’s a waste of energy to use your arms for propulsion, so the proper swimming position is with both arms folded across your torso to minimize drag. Arm movements are really only useful for close-in maneuvers and sharp turns.

Buoyancy Control and Breath Control

Buoyancy control is a critical dive skill. You manage your buoyancy using three vessels, or balloons: The BCD, which contains an air bladder, your drysuit, which is a kind of bag, and your lungs.

Most new divers have some challenges attaining neutral buoyancy and staying neutral throughout a dive. It’s common for new divers to get caught up and struggle in a zigzag pattern. Zigzagging happens if the diver is too slow to react or overcompensates for small changes in buoyancy.

To understand what is happening to such a diver, visualize a tug of war rope, with forces trying to make you float pulling one way and forces trying to make you sink pulling the other.

Imagine that you’re all geared up and in the water, floating on the surface but not swimming. Forces to make you sink include your body weight plus the weight of the gear you’re wearing. The force trying to make you float is the volume of water that you’re displacing. The more water displaced, the more buoyant you will become. If your BCD is full of air and there is air in your drysuit,  you’re displacing the maximum volume of water and will float high in the water. If you now purge excess air from the drysuit, exhaust air from the BCD and exhale to empty your lungs, you’ll displace much less water, so the weight of your body and equipment will cause you to sink.

The BCD is a big balloon and your main tool for establishing and maintaining the balance between the forces to sink and to float. Its’ low-pressure inflator/deflator hose is the equivalent of a car’s steering wheel. You need to be holding onto it at all times (except when checking your gauges) and making lots of small adjustments just like you would driving on city streets. As you dive deeper, air in the BCD will be compressed by  the increasing pressure, so you need to add air to maintain neutral buoyancy and prevent sinking. Conversely, as you move up from deeper water to shallower water, pressure decreases so the air in your BCD will expand. You will need to exhaust air from the BCD to maintain neutral buoyancy and prevent an out-of-control ascent.

Imagine that you’re mid water and hovering motionless, neutrally buoyant. If you press the inflator valve for one second, to add air to the BCD, you will become positively buoyant. You will feel the weight of the BCD lifting off your shoulders and pulling you upwards. Likewise if you instead held the exhaust button down for a second, the BCD would dump air and feel heavier on your shoulders. Over time and with practice, you will get the feel for this weight of the BCD on your shoulders, which is an early warning that you are losing neutral buoyancy.

Your drysuit is connected to your tank air by a low-pressure hose. You control the volume of air inside the drysuit with an inflator button and an exhaust valve.  Add air when you're descending and exhaust air when ascending.  Use your right hand to deploy both the inflator and deflator buttons.

Breath control is a critical dive skill that can only be mastered over time. Imagine that you’re underwater and neutrally buoyant, hovering motionless because the forces are in balance. When you inhale, your lungs expand and you displace a little more water so you’ll tend to rise slightly. When you exhale, you tend to sink slightly. If you breathe calmly, deeply and rhythmically, your breathing won’t affect your overall buoyancy. But many new divers are a little anxious, so their breathing is fast and shallow. They never empty their lungs fully, so they tend to make themselves positively buoyant. Also, by not inhaling deeply and exhaling fully, they fail to eliminate carbon dioxide, so the breathing reflex is continually being triggered. This failure to breathe and oxygenate fully can easily cut bottom times by 50% as the diver sucks the tank dry.

Good breath control skills will enable you to fine tune your vertical position in the water column without adjusting the volume of air in your BCD or drysuit. This is an especially important skill for photographers when hovering around a subject.

It’s important to add or exhaust air in small increments, to avoid overcompensating and flinging yourself in the opposite direction. The proper way to hold the BCD inflator hose is in a pistol grip,  with fingers and thumb positioned to press the inflate and exhaust buttons as needed.  With this kind of grip, you will be able to make quick adjustments and even be in position to inflate your BCD orally if necessary. If you need to exhaust air, lift your left arm as high as it will go as you press the exhaust button, to make sure that air is efficiently exhausted from the BCD. Watch the bubbles as you exhaust the air, to see how much you have dumped. And while you're swimming along at a constant pace over longer distances, the proper position for your arms is tucked-in and folded across your torso.

While some new divers tend to positive buoyancy, others tend to keep sinking. Resist the temptation to swish your arms when you’re sinking. It’s too little compensation and a waste of energy. Instead, squeeze the inflator button. Likewise, if you start to feel yourself rising, quickly lift the deflator hose upward from your chest and press the exhaust for a second, or two seconds max. Watch the bubbles to see how much air you’re releasing. You would only want to empty the BCD if you were in an uncontrolled ascent, so don’t overcompensate.

Poor body positioning and a bad finning technique can also affect your buoyancy. Ideally, you want your body to be almost horizontal in the water so that you’re swimming horizontally and maintaining a vector that keeps you at a constant depth. Any significant change in depth caused by swimming vertically will eventually shift your buoyancy from neutral to either negative or positive. So if you are swimming vertically, be prepared to make a significant adjustment to the volume of air in the BCD. And be prepared to adjust the air in your drysuit.

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Posted on February 17, 2013 .