I second/third drenching your hair with water and conditioner prior to jumping in the pool. This is what I did back in high school when I was relaxed and we had swimming for like two months or something. I drenched my hair in water and Pantene, put on a shower cap, put on my swimming cap, and called it a day. After swim class was over, I rinsed the conditioner out of my hair and went to my next class. I didn't suffer any damage/breakage.