I'm going to have to credit this one to Boyle, he mentioned swimmers training on land in his FSC DVD.
Swimmers are in gravity free environment all the time, this is why swimmers should squat, and why they need strength training. Swimmers adaptations will be in the reduced gravity environment this is why they need to get out, be on their feet and use all those muscles.
As far as the split between dry and wet training goes. I would keep the bulk of my training in the water. Dry land training is a big staple in the swimming world, if done intelligently. Take a look at what's stopping you from going faster in the water, and fix it on land. For example take a look at your typical swimmer and their posture. Pronated shoulders, tight pecs, and lats, is this helping them in the water? Why are the coaching not spotting these problems?
I myself had shoulder issues when swam, due to tight pecs, lats and other factors that lead to "swimmers shoulder" syndrome. What did my coach have us doing in the weight room? What ever we wanted. My teammates and I didn’t know any better so we benched!
