Straight from Urban Dictionary...

"Waterman"
A guy who is really at ease with all water activites. He is "the man" when it comes to windsurfing, waterskiing, wakeboarding, sailing, jetskiing, parasailing. He is also a very capable skuba diver and sea kayaker. Usually exudes an air of arrogance and can be thought of as being a complete knob. But still he is the king when it comes to water activities. (Isn't totally opposed to golden showers)