Swimming is something that, if you leave childhood as a weak practitioner, you will almost always remain that way- except that swimming is a skill like any other that can be improved upon. You may fall in a raging torrent, have to swim from a wrecked boat or swim out to ruins half submerged in the sea. All this requires good swimming skills.
I have improved my swimming, especially the front crawl, by applying a number of simple principles.
The main one is that the object of moving the arms and legs is not staying above the surface but propelling you forward. If you are keeping afloat through arm and leg strokes you will always tire easily and swim slowly. The object is to just FLOAT in a ‘fast’ shape (as pointed and flat as possible) and use the arms to keep you moving forward. It’s that simple. If you use your arms to keep your body high in the water you are wasting a ton of energy.
The first step in relearning how to swim is to float and stretch out and get used to that position in the water. If your mouth is under water get used to twisting it sideways to breathe. Wear goggles if chlorine annoys you. Dr’s Proplugs, which are used by freedivers, are well worth wearing to avoid ear infections if you are spending lots of time in the water.
Now start the stroke. The secret is in its prolongation and relaxed nature. The returning arm slaps or cuts the water with great ease not manic energy. The power only comes on- long and smooth- whilst the arm is under water, swirling lengthways and longways as long under water as it can maxxing the forward motion out of every stroke made. As soon as one is almost finished before the pointed projectile of your body halts the next arm has slipped in and is powering ahead. The legs? Just flip them up and down to keep time, keep them busy- they are of no importance in keeping up the power- they are moved to just ease the way forward and keep from flopping down and spoiling your hydrodynamics.
Breast stroke and Butterfly can both benefit from the low in the water, relaxed and maxxed out stroke indicated above. Watch top swimmers and see how far they go on a single stroke- you can too as long as your body floats.