현재 위치: 홈1/Teaching Neutrally Buoyant and Trimmed: Pt2 – Mask, Snorkel &...
Teaching Neutrally Buoyant and Trimmed: Pt2 – Mask, Snorkel & Fin Skills
By Kosta Koeman
In the first blog post, I explained some of the physics involved with teaching neutrally buoyant and trimmed, and the consequences of overweighting students. In this post, I’m going to focus on preparing students for scuba through a series of mask and snorkel exercises, finning practice, and skin diving.
Just a snorkel and a mask
Unless open water students have prior experience with Try Scuba experiences or skin diving, the idea of breathing underwater from a regulator is foreign, and possibly quite stressful for many students. Mask clearing skills are another stressful set of skills for many people. A myth persists that having students neutrally buoyant at the start is “too much.” Admittedly, while some people are like fish in water, a few others find going straight to being neutrally buoyant and trimmed to be too large of an initial step with scuba. It can be counterproductive to place some students underwater immediately as the stress that some feel hinders their learning and skills acquisition through the entire course.
The exercises I am about to describe mitigate the risk of students being overwhelmed. Why? Because by the time they actually put on scuba gear, they will have performed a number of exercises that simulate or replicate a number of scuba skills that they will then perform underwater. The actual skills won’t be dramatically new for them.
They will have familiarity and the confidence that they can perform these skills, which are:
Partial flood mask and clear
Full flood mask and clear
Regulator oral purge
Snorkel oral purge
This is why I start a few short exercises with a snorkel and a mask that take about 15 to a maximum of 20 minutes. I want to eliminate the stress of being underwater breathing from a regulator, having one’s face in the water without a mask and/or regulator/snorkel, and clearing the mask/snorkel.
Start with a few short exercises using a snorkel
You start with your students standing in chest-deep water. Their knowing that they can stand up at any time reduces the stress factor of “being trapped” where they may panic and bolt to the surface. Verbal communication is possible by simply standing up. These exercises that I will now describe prepare students for performing a number of skills while on scuba. While performing them with mask and snorkel takes some time, students perform the corresponding scuba skills faster with more confidence, resulting in overall time saving. This is especially helpful if there is limited pool time and can allow for fun “games” that task load students while practicing neutral buoyancy after all students have demonstrated proficiency.
Standing in chest deep water holding their snorkel with the mouthpiece in their mouths, instruct your students to crouch down and at first breath in and out through their mouths while keeping their eyes above the surface of the water and their nostrils below. This prepares them for normal breathing through a regulator. This also trains them to not inhale a little through their noses inadvertently while wearing a mask, as doing so, they may inhale some water up their noses while performing mask clearing skills. It also trains them to not exhale through their nose which can fog up their masks.
Watch to ensure that they make no bubbles that would occur by exhaling through the nose. Have your students to perform yoga-like breaths, deep and relaxing inhalations and exhalations. These slow breathing patterns have the benefit of relaxation and develops the habit of breathing in this manner. As soon as your students are ready, have them place their faces completely in the water, but keep the back of their heads above the surface, monitoring that they continue to slowly breath with their faces in the water. This starts to prepare students for mask removal and clearing skills, keeping calm through slow, deep breathing.
In continuing to prepare students for mask removal and clearing exercises, have the students take in deep breaths and exhale hard out of their noses. First with their eyes above the surface and then with their faces completely in the water. Ensure that a blast of bubbles occurs on every exhalation.
For the final snorkel exercise without a mask, have your students stand up, take in a deep breath without the snorkel in their mouths, place their faces and the mouthpiece of their snorkel into the water, and have them exhale suddenly to blast the water out of the snorkel.
Exercises with Mask and Snorkel
With adding a mask, the focus is on preparing for clearing water from their masks. Students bend forward to, partially fill their masks, stand up, and with one hand pressed against the top of their mask, they exhale through their nose to clear the mask. They repeat this, but fully flooding their masks before standing up and clearing.
Next, students will bend forward into the water, look horizontally, fill their masks partially and then fully, and clear them while keeping their heads mostly underwater while looking forward and clear their masks. Finally, have students lay on the surface of the water, and repeat.
Before I move onto skin diving, I teach frog kicks so students develop a feel for the control they get from their fins. I start first on dry land, which is nothing new, demonstrating the movements laying on a flat surface, and then guiding students fins as they try the same (in my next open water class, I plan on using a USB camera attached to my laptop for my students to view in real time). Now this is a little awkward, as there is friction of the upper thighs, and also the legs are heavier than in water. But this has value in getting students to understand the mechanics of the frog kick. Confined water is where students get the hang of frog kicking. In confined water, I have the students lay on their backs to practice. In this position, if their knees break the surface, then they are breaking at the waist. This is a comfortable manner to learning how their body will feel with the upper thighs and the torso in a straight line. I have tried correcting body positioning underwater, but it is far more cumbersome than at the surface.
Before moving onto skin diving, I have students practice butterfly kicks at the surface with just mask, fins, and snorkel. I tell them (and then demonstrate) to focus on kicking “from the hips”, pointing their toes slightly, with no bending of the knees during the downstroke, and kicking slowly to get the feel of the power involved with properly performing this technique.
The benefit of teaching skin diving prior to scuba is that students practice finning techniques underwater, equalizing, and clearing the snorkel with two different methods.
Discuss different equalizing techniques with your students. DAN has provided an excellent article, “Beat the Squeeze: Equalize Like a Pro.” Even diving to shallow depths can cause discomfort or pain for many people. After practicing at the surface different equalizing techniques, move onto snorkel clearing methods: blast and displacement. The former involves a strong exhale once the snorkel breaks the surface to clear it. The latter involves the snorkel pointing down with the diver exhaling slightly to displace all the water with the air from the lungs and taking advantage of gas expansion as pressure decreases. Upon reaching the surface, the diver gets in a flat position pointing the snorkel up, and can inhale. Have students dive down vertically and equalize, swim horizontally, before coming back to the surface to clear their snorkel using the two different methods. I am not going into much detail, as I expect instructors already know how to teach skin diving. The point is to have students learn skin diving techniques prior to putting on their scuba kit.
There’s another benefit to teaching skin diving prior to putting on scuba gear: learning to be horizontal. You go straight where your body is pointed.
Future Blog Posts
In this post, we covered a set of exercises that reduce the size of steps later taken to get students neutrally buoyant and trimmed, and introduced some of the skills that they will perform while in scuba equipment. Coming up next in this blog series is the weighting procedure I use for getting students properly weighted and that weight properly distributed so that the center of mass matches the center of buoyancy horizontally.
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