Convention uses standard off the shelf boards or sheets in 18mm thickness. Sized 2440mm x 1220mm they are the metric equivalent of the old money 8’x4’ sheets. Available in a wide variety of hardwood facing materials for a decorative finish, sheets are also available in a variety of materials.
MDF is cheap, but not very moisture resistant in its most common form. Exterior grades are available but you may find sourcing veneered external quality boards difficult. Whilst easy to work and shape, the screw or fixing holding power of MDF is poor.
For standard MDF, veneered surface finishes are extensive and commonly include ash, oak, maple, cherry, beech walnut and pine. In standard sheet size of 2440mm x 1220mm the thickness for bulkhead use is 18mm or 19mm. Larger sheets are available sized 2440mm x 1830mm in 25mm thickness or 3050mm x 1220mm in both 18mm and 25mm thicknesses. The range of surface veneers is likely to be reduced in the larger sizes.
Block board is lightweight and dimensionally stable. It is produced by laminating strips of wood between ply sheets. Check with your local supplier but you may struggle getting Class 2 moisture resistant products.
Veneer faced plywood is commonly available in both Class 2 and Class 3 grades. Specialist suppliers can supply board in literally hundreds of laminated surface finishes. Commonly available in the standard sheet size of 2440mm x 1220mm, some finishes may be available in larger sheets should you wish. It’s best to check with your local timber merchant on availability and suitability of materials for your choice of application.
Choose hardwood ply over cheaper spruce. Spruce ply has its place in the market but not for bulkheads (or floors). Spruce is softwood which has the benefit of being lightweight and low cost but it is soft and will deform over time in a marine environment..
Bulkheads will be subject to moisture, especially the ones that form the boundaries of galleys and, especially, bathrooms. For this reason we recommend fitting the best quality you can justifiably afford. In the case of laminated or veneered wood surface finishes be prepared to seal the grain to avoid staining and cracking in use. Specialist varnishes and lacquers are available that will give a variety of surface texture and style from the high gloss of yacht varnish to stained and matt finishes.
Bulkheads can be fitted before or after first-fix electrics. However, it is easier to plan room lighting schemes if the bulkheads are in position, so we would suggest fitting them before the lighting tails are planned. Bulkheads will completely change the natural lighting inside your canal boat. They may also help you to visualise the position of beds, showers, galley fittings, fire position, waste tanks and entry steps. Those of you with good visualisation skills and highly developed design and planning awareness may wish to get the first-fix out of the way. There is no doubt it is easier to move around the boat without bulkheads!
Once the bulkheads are installed it is time to get the tape out again and re-measure because things are bound to have changed a bit.
It is pretty important that the bulkheads are fitted accurately with reference to the equipment that will be fitted into the room. Your shower tray, toilet and sink unit will require a certain amount of space to fit that is not negotiable. Being 15mm short with your measurements for bathroom bulkheads could be a real pain!
Think also about your bed. We know the two most popular types of bed are either the fixed double that runs fore/aft or the make-up cross ways double which runs port/starboard.
Fixed double mattresses are a standard 4’ or 1219mm. Bulkhead panels are a metric 1220mm wide. You don’t have a lot of room to play with to avoid an overhang; especially if the bulkhead panel is inset into the side wall lining panels by a few mm. Consider fillet strips either side of the bulkhead to increase the effective width of the panel. Or simply live with the overhang of the bed. Either way it’s your choice but be aware of the considerations. One solution may be to utilise a standard 4’ mattress but have a customised full length width extension made to 6” or so. The bed could then pull out into the corridor slightly and the extension piece drop into the void created under the gunwale. Either way, whether considering bulkheads for bedroom division, your choice of bed will come down to whether you want a permanently made-up double or a bed you have to construct every evening.
Fix bulkheads to side and ceiling batons and sub-floors by angled screws. A pocket-hole jig is a really effective tool for making accurate angled guide holes on timber panels or framework. Available for just a few pounds from the internet or good tool suppliers you will use this tool again and again, especially when constructing furniture framework. The addition of the ceiling and wall panels will add strength to the bulkhead so don’t worry too much if it seems a bit flimsy before the lining out is done fully.