This question came up the other day but in a lot of cases you can''t just slip the bulkhead in because the original bulkhead was installed before the deck went on. The way to handle that is to build the bulkhead out of two layers of plywood that are half the thickness of the original bulkhead with each layer being split in half horizontally. The split should be offset horizontally by perhaps a foot or so. The one that I did I sealed all of the edges and faces of the new bulkhead with epoxy and then epoxied the pieces together during installation. You should have a rubber strip around the edge of the bulkhead so that the bulkhead does not actually touch the hull. Tabbing can be very difficult on some of these newer boats were there is a hull liner against the bulkhead at the hull and deck. There is no easy answer except that you will need to cut away the liner. If you make a careful cut you should be able to put the liner back when you are done. One word of caution, on a lot of newer designs there is a main transverse frame molded into the liner and that frame should not be cut. I suggest that you go with wide tabbing and that the tabbing be tapered at its edges.