I'm unhappy to report that
When I held him around the chest, he desultorily stroked his front legs through the water (displacing almost none), barely paddled his hind feet, and called it done. He held his head majestically the whole time, either completely oblivious to, or uncaring of, the fact that I was the one propelling him through the water and simultaneously keeping him from drowning.
It was hilarious!
My girls spent the entire afternoon and evening in the water, until the skeeters drove them from the lake about half an hour after sunset.
I, however, after my dog-towing duties were complete, wrapped myself in a towel and vegged out on the gazebo, sipping booze with my feet up and enjoying the sunset.
Life is very sweet.