I've done that trying to clear off a pond to make a hockey rink. What I did was to seal the exhaust with a rubber plug and put a chain onto the front axle. Then chop the front wheels loose and let her set on the pond bottom. Hook the chain to the the next available tractor and yank her out. Pull the plug, check for cranking ability (lockup), check air cleaner and oil level. Go plow the driveway instead. There was not an oil slick on the water, so I figured she was not leaking in or out.
That was "back when I knew it all"...