.....mmm......couldn't get a download on this link...but I remember we had fun here on SimV with floating 747 and in fact any aircraft quite some time ago....
What determines whether a plane swims or just takes off from the runway is the class as stated in the contact points section of the aircraft .cfg.....
Class 1 – Wheel
Class 2 – Scrape Point
Class 3 – Ski
Class 4 – Float
So simply changing the first entry (class) of the first three lines of the contact points from 1 to 4 will give it floats instead of wheels.........
Other things may need consideration if making a float plane but in the case of the Hudson water landing the rest of the .cfg should be just left as is maybe.........commoner
Have fun......commoner