CMISCHEL....Save yourself the time and expense of getting a centerboard for you 30' O'Day. I have a 1983 30' O'Day with a centerboard and I I've sailed with it down and in the up position and didn't notice any difference. The only time I have noticed a difference is pulling into a slip with a cross wind and it will help keeping the boat in a straight line. When you do sail with it down it will make noise and bang around if you don't have a stiff breeze. It's a pain in the butt to replace the pendent without hauling the boat. When you are planning to haul your boat for bottom painting you have to find a yard that will hang your boat up high enough on their travel lift so you can lower and paint the centerboard and the inside of the centerboard trunk with enough time for the paint to dry properly. You will have no problem enjoying the 30' O'Day without the centerboard.