If you have water damage to the bottom edge of Masonite hardboard siding, it can be covered. Board and batt siding consists of 4' wide sheets with a 1-1/2" batt nailed vertically every 16". If the siding has bubbled at the bottom, it is because of water damage.
With a circular saw, cut the batts up from the bottom 5 1/2" (the width of a 1X6). Nail a cedar 1X6 to the bottom, butted up to the batts. Caulk the top edge and paint.