Boat Insurance and ballast systems

Have any one you had your insurance company ask on a form or in person if you modified your boat in any way? I am wondering... do I fes up and say I have a custom ballast system that adds another 800 lbs of water and includes hoses, pumps and check valves? I bet they will raise my rate, but I am concerned they won't cover me. If they raise it $100 a year, I can live with that. If they say "no way" will we insure you with that ballast system... then I am screwed...