Originally Posted by Jizm
Have a word with cooke on here he may be of some help with ballast systems.
I knew it was only a question of time before I got dragged in ............
You'll need a largeish pipe running down the keel to the transom where you will need a "pick up and dump" fitting that is operated by a control cable and a hand throttle - usually forward to pick up, neutral to hold and back to dump - the tank will need a minimum of double sized vents to allow air and water to escape, this can either be a bow or central ballast arrangement.
Having said all of that I wouldn't bother - unless you're racing or the design is totally unbalanced in which case extra weight probable won't help!