I have noticed a funny synergy between my arms and legs, and sometimes when I am close to cramping and I "pull" hard with my upper limb, I can feel the tension in my contra-lateral leg. No doubt this is some nervous system mechanism similar to swinging your arms when you walk and it must have its origins in four-legged locomotion.
In any case, I avoided the cramp and swam a good pace too. Probably close to 2:00 per 100m. OK, I know that is nothing to write home about, but for me it is. If I could do that in an Ironman and all else fell into place, I would get my long coveted Hawaii slot for sure.
Another interesting observation is that I lost 2 pounds while in the pool. I weighed in beforehand at 174 and after I was at 172. The swim took a little over an hour and the pool is pretty warm. I am sure most competitive swimmers would say it is too hot.
I am glad to say though that swimming is a lot easier now. The long swims really do help.