Once any stringers and ribs are in place, the next big job is to install the bulkheads.   In some cases, the bulkheads may be fitted before the webs, where the bulkhead itself serves as a web.   Bulkheads are generally made of one or more sheet of plywood.   As most boats are wider than the available plywood sheets, you can order pre-scarfed plywood or rebate and glue the sheets although this is not as strong but, with furniture attached, there is little difference by the time the boat is finished. Another method is to make the bulkheads out of more than one layer of plywood.   In the case of ½” [12mm] bulkheads you can laminate two layers of ¼” [6mm] and for ¾” [20mm] you can laminate two layers of 3/8” [10mm] and so forth.   Stagger the joins of the sheets and glue and temporally staple together.   Before you bond the bulkhead to the hull, be sure to give it a prime coat of resin, where it is to be bonded.   This prime coat should extend all around the edge of the bulkhead and about 6” [150mm] on to the bulkhead surface.  As you will probably want to paint the bulkhead, at a later time, limit the resin to areas where you will be bonding only. Generally speaking, epoxy resins and glues can be used over polyester but not the other way and it is best to have bare plywood for any bonding and gluing.

   In many cases, bulkheads will be installed on a rib where an angle joint of fibreglass should be extended for 4” to 6” [100mm to 150mm] on to the hull and the bulkhead reducing a small amount each layer to avoid a hump.   A number of holes of about 2” [50mm] diameter may be cut around the perimeter of the bulkhead then chamfered from both sides to accept the fibreglass.   The bulkhead bonding will then be joined from each side, through these holes, greatly increasing the strength of the bulkhead to hull join.

   Only the main structural bulkheads need to be installed at this stage.   These will be arranged so that the tops are allowed to rise far enough above the sheerline of the hull to allow for the shape of the deck and cabin including the cabin top cambers.   On larger pleasure boats and on most commercial vessels, it may be necessary to have some form of bulkhead stiffening which will be shown in the plans.   In small to medium size boats,   the bulkhead stiffening may take the form of the framing for the furniture and joinery, which will be fastened to the bulkhead.   It is possible to make the bulkheads from fibreglass using core materials such as Balsa or PVC foam, but our experience shows it is better to make the bulkheads from plywood unless there is some compelling reason to use fibreglass sandwich - such as incorporating furniture into the bulkhead.