I have taken the lead out of the front of my boat and replaced it with some steel disks. I got them from a washer manufacturer, its the centre they punch out. At about 10cents a pound it works out to be the cheapest form of compact ballast I have found. I sprayed it with WD40 then double plastic bagged it. Each bag weights 22-25 pounds, I have 8 in my chain locker and a couple more under the bow seats.