I finished putting lead disks at the bottom end of my centerboard on my 3.5 meter sailboat. I have tipped the boat over twice in heavy winds so I decided it was high time to get a bit more ballast (as the original plans advised, he admits sheepishly). I found lead from a local gas station: weights taken off from tire changes and melted them down in my sauna fireplace. I was advised by an old friend to make sure there was good ventilation as lead fumes are highly poisonous. It was ok ... the fumes went right up the chimney. Now the centerboard is most definitely heavier where it counts at the bottom tip.