Installing a bathtub isn’t exactly rocket science, but it does require solid plumbing, carpentry, and sometimes, tiling skills. Replacing an old bathtub with a new one is also a moderately difficult project. If the old tub is readily accessible, the project can move speedily; if you have to open a wall to remove the old tub and position the new bathtub, the task is much harder. In either case, the project is within a home handyman’s skills, although you will…