I am not sure of the specific cost but a keel is not cheap. Then you have the cost of shipping from Canada where Mars Metals is located, lifting off truck, travel lift to lift up the boat for removal and install, materials to include bottom paints, sealants and labor. To do that by a do it your self individual is very dangerous on a 42 foot boat because one thing is to properly position that new keel under the boat upright and if you do not have the where all or intelligence to do that, I would encourage anyone to let a professional do that. I speak from experience as a former dealer as that keel weighs a lot.