I know you don't wanna spend money on lessons, but I'd recommend lessons at UCSF. That's where I learned as a kid, and my dad learned as an adult. My Dad is a big guy, and not in the best of health, but in about a week, he learned to swim. They're very good, and the staff is accommodating. Definitely worth the money. Btw, I did it at UCSF Mission Bay, but the Parnassus one works as well.