I don't kick my legs very much at all. You are right that leg-action is not critical, nor, to a certain extent, is arm action (bear with me!) but it is the movement of your body as one through the water, the twisting of the torso, stretching the arms far in front of your head and so on...

Angle the body so that it cuts through the water like one of those racing yachts, don't lie flat in the water pushing through it like a barge - was how I had it explained.

I tried swim practice with some fellas that really knew how to swim. They strapped these thick black rubber bands around their ankles so their legs were never gonna kick, then they swam lengths. My life! I had to put a pullbuoy between my legs to stop my feet craashing through the pool tiles...

Mud - if you swim in ullswater, swim behind someone, you can get in the equivalent of their bicycle slipstream... it does work.

Daleside - I agree with you on the leg/arm thing. My excuse was that a runner's legs are muscle, thus heavy, thus harder to keep afloat.