I've taught kids swimming, and believe you can get even the worst swimmer to become comfortable in water. It is always possible, just the older you do it, the more you have to unlearn first.Also very hard to teach without being there and hands on, but I'll give it a go.
First, dispel a myth. Body fat or muscle mass has nothing to do with your ability to float. Look at all the Olympic swimmers, they have 0 fat and are built like a pile of bricks. Put anyone motionless in water and they will sink (either that or they are holding in a huge breath which they will eventually have to let out...then they will sink). No matter how you are built, you can float, tread water, swim.
Second, you have to become comfortable in water. From what you have written, and from what I have seen of people learning to swim, the biggest hurdle to overcome is the feeling that you are going to slip underwater and drown at any point. Like most things, learn to walk before you, er, swim.
There are several steps to do this. Do them in order, and do not progress to the next until you are 100% happy doing each one
1. Become comfortable under the water, so that you don't feel like being underwater is automatically dangerous (most strokes, done properly, require being underwater). Do this, at first in the shallow end, by simply sinking your head under the water while holding your breath. If you like, do it by lying flat down in the water (warn lifeguards!). Do this for 10-20 seconds, then increase the time.
Next, sink underwater and sit on the bottom. You can easily push off the bottom and right up to the surface in one motion. When comfortable with that, move around as much as you can underwater. Work out which motions are the most effective for movement, which are best for turning, how to go fast, etc. All underwater. When you are comfortable with this, try it in the deeper water. Just play around!
Also try being underwater having exhaled all your breath. Do this in the shallow end only. You will be able to tell a huge difference between how your body moves and your buoyancy (how you float) when holding a breath and without a breath. Try this exercise: In the shallow end of your pool, sitting with your legs crossed or kneeling so that you are submerged to your chin. Try and have your legs as relaxed as possible so you can bob up and down. Then take in a huge breath quite slowly, and let it out at the same pace. Feel how much your whole body will rise and fall in the water.
This will be important for step 2...
2. Treading water. It's a misnomer. Your legs have little to do with it. First, what keeps you afloat?
Three things. Air in your lungs, your movement (both obvious) and your mind (opinion). The air in your lungs gives you 99% of your buoyancy which keeps your body afloat (on the surface) or at a level (underwater).
Breath Remember the effect your breath had on you floating. Become used to, when treading water, always keeping your lungs half full. Only breath out about 1/2 way, and hold the rest in your lungs - this should give you more than enough buoyancy to keep afloat.
Movement Think of a water-boatman on a pond (those thin insects which skate on the top of the water), that is how you want to move while treading water - it is very much like being in a swamp or quicksand, you want to spread yourself on the surface as much as possible.
Arms. Practice this at first with your legs on the floor in shallowish water. Move your arms in a long sweeping motion with your palms facing down at chest height - your hands sweeping out from your chest in a semi-circle and back again (remember wax-on, wax-off from Karate Kid? a little like that). Practice it until you can feel the lift created by your arms (like the water is pushing up against them). The faster you do it, the more lift it will create, and the more it will keep you afloat (but the more tired you become). You can actually do it very slowly when practiced.
Legs. Various ways to do this, do what you are most comfortable with. I personally use a scissor kick (not footballing, a breastroke kick), kicking your legs out like a frog quite slowly. If you are doing the breath and arms correctly, your legs are barely needed. The normal way people are taught to tread water (paddling your legs to and fro) is actually the worst way, see below if interested.
Mind If you think you will sink, or are in danger, then you will get uncertain or panicky. Your natural panic response in water is to lash out and breath fast. Both of these things, as shown above, will only make you sink further. That is how people can drown even in shallow water; however, I have never heard of a good swimmer drowning because they panic treading water - they drown from injury, cramp, overstretching themselves or being stranded and tiring. Once you learn to tread water comfortably, you break a huge psychological barrier where you no longer feel the need to hold onto something in the water to relax. It is your safety net, and once you can do it, learning to swim strokes will become a thousand times easier. Get your breath and movement right treading water, and your head will fall in line.
Stick all these three together, and you should be treading water comfortably. You must be comfortable underwater and treading water to begin to swim. The major error of swimming teaching is to rush kids to 'real' swimming strokes before they are comfortable in water. They then never become comfortable with any of it, and don't like swimming.
Technical stuff inc quite helpful for understanding how all this works: to stay afloat, you need to your buoyancy to be greater than your mass. Mass = your weight dragging you down. What you are doing with movement and position is off-setting your mass and spreading it over a large area, so less pressure is pushing down / weight pulling down at any one point, causing you to sink (this is why you lie spread out on quicksand). Thus the worst thing you can do while trying to float is to make your body like an arrow pointing straight down - conversely, think of a high-board diver, that is exactly the position they hit the water for, because it offers the least resistance. Ironically, this is the position most people are taught to tread water in. The teachers are wrong, ignore them.
3. Once you are treading water, you can start practicing strokes. The most important thing here, in my opinion, is to play. Just mess around in the water, feel it out for yourself. Once you feel comfortable in water, you will teach yourself to swim. Four basic maxims though.
Rule 1 - Remember the water-boatman / quicksand position. Always while swimming you want to keep your body just floating on top of the water with the momentum of your stroke keeping you there. Always keep your body as level and horizontal as possible (arching your back or anywhere else, as described above, will just upset your centre of mass and make you sink).
Rule 2 - Get your head wet. So many people, particularly doing breastroke, but also crawl, try and keep their bloody heads out of the water. Again, this is puts the balance of your body out of whack, and forces usually your torso or lower back further under the water. This makes you sink, and makes it a struggle to swim. I would also guess it is none too good for your spine.
Crawl, the head should be flat down in the water, looking at the bottom of pool, turning to breath only so you are looking sideways and your mouth breaks the surface. You should NOT be moving your head from side to side above the water with each stroke.
Breaststroke, when your arms start the stroke, your head should follow them under the water, breaking the surface again to breath as your arms come past your chest to start the next stroke. You should NOT have your head always above the water with your arms moving in tiny circular paddling motions, at least not unless you are a 65-year old matron along for her monthly aquaerobics class.
Rule 3 - The path of least resistance is the best 90% of the time when I see someone swimming badly, it is because they are making a huge effort to little effect. Make the smallest motion and cover the shortest distance neccessary to get the effect.
Rule 4 - Momentum Since you are going to be breathing hard and full while swimming, air in your lungs no longer plays such a large part in keeping you afloat. In it's place is the momentum you have in the water (this is why it is easiest to start with a dive or pushing off the side of a pool). Whichever part of your body is doing the work is propelling you forward and pushing you up against the water to keep you afloat at the same time: you can swim crawl with only your arms so they are the engine pulling the rest of your body along; you can just use a scissor kick (frog kick) to push yourself forward. Most strokes combine the legs and the arms working for speed, ease and so that the forces pushing your pody up to keep you afloat have no dead weight dragging you down. Remember though, that any motionless part of your body is potential dead weight, and will cause drag if out of the horizontal position (ie stop moving a leg and let it fall downwards, see how it tries to pull the rest of your body with it). To prevent this make sure your entire body moves with the flow of your stroke; do not actively try to move your torso by arching your back or so on, but let it gently twist or rock with a crawl stroke, or ripple like a dolphin moving with breaststroke or butterfly. Try and be aware of how this works while learning strokes, and you will quickly feel how to instinctively streamline your body.
Aside from that, you need someone there with you to teach actual strokes, explaining them is one thing, but you need someone to correct mistakes. Watch competition swimming if you see some on tv, the underwater shots give you a great view of stroke techniques. Also (and here it gets a bit Sun Tzu Art of Swimming) have a look at how dolphins, whales, sharks, submarines, frogs, eels, and so on, move underwater - every human stroke has stolen technique from various animals, as there are actually very few efficient ways of moving yourself through water.
If you do the above three steps, however, you can learn to be comfortable in water. After that you will no longer be a bad swimmer, as you will no longer be fighting against the water every second. After that, you should hopefully enjoy it! Just play around, have fun, and learn for yourself
Well that was a fecking essay, wasn't it...
) to help you if you need to see how its done.
