Keel/Rudder fairing
Curtis;One big no-no is to use Bondo to fill/fair any below the waterline repair.Use only a good epoxy type filler such as Formula 27 available at your local West Marine store. Without seeing just what you are have I can not offer too detailed advise. [WEST System epoxy can be made into a nice slick easy to sand fairing "putty" by adding Cabosil & Micro Balloons to the mix, however if you have no experience with this, I'd stay with the Formula 27.]If the old filler is a dark red color, it is more than likely Bondo.Many boatyards of questionable repute use it[cheap],but it wicks up water and will fail eventually.I would take the time to grind it all out and replace with some epoxy type filler.Hopefully you have just a few small areas to do and not the entire keel?Since you say you will not be racing, fairing by eye & feel is the way to go rather than using NACA section templates. Once the keel looks & feels, to your touch, the way you want it,I would roll on a coat of VC Tar2(InterLux) to seal the whole keel and then it's your choise of bottom paint.Lot's of luck! CaptHawks/v RogueWave