By now you will have constructed and assembled all of the elements of the framework. Now you can start to install the frames on the strongback or bedlogs. A tensioned wire marks the centreline of the building jig. This wire will remain in position until the hull is turned upright.
You’ll need a carpenter’s rule, a steel measuring tape (at least as long as your boat), a plumb bob, a large carpenter’s square, a spirit level about 3 feet (1 m) long, and a line spirit level. Each frame must be square off the strongback, and must be parallel with its neighbour. Use the plumb bob to ensure the frame is vertical.
After you’ve marked out the strongback or bedlogs with the correct station spacing, you can start with station 5 or the midsection frame (the same frame in many cases) and install it firmly in position. Work alternatively fore and aft, installing the frames until they’re all in place. Needless to say, you should check everything several times until you’re absolutely sure the whole structure is true and fair. We have seen boats with stems that are crooked and keels whose leading edges are out of line; it’s really a sad sight. Your eye will be one of your best guides to fairness; use it, and then check again by measuring and use the level, square and plumb bob to ensure you have everything set up true and fair. There is a trick to avoid having the frames cause a "starved cow" look in the final plating. The frames ahead of the midsection should have their forward edges on the spacing line and the frames aft of the midsection should be installed so their aft edges are on the spacing line. The result is that when the plating crosses the frame, only one edge of the frame touches the plating, and the plate is not fighting its way around the frame.
Next, install the stem, the aft centreline bar, and the centreline transom bar. The transom may be left off at this stage and not installed until after the plating is completed on the remainder of the hull. Generally, you don’t install the keel sides or the bottom of the keel plate until after the hull is plated and has the strength to support the heavier plating that is usually specified for the keel. In some designs we have specified 1/2 inch (12 mm) plate for the bottom of the keel; the idea being that this forms part of the ballast. You may substitute this for 1/4 inch (6 mm) plate as this will make for easier handling of the bottom of keel plate.
In some designs, a few of the bulkheads may be included as frames; this works fine, providing you do not change your interior plan after the bulkheads have been installed. The bulkheads at the forward and aft ends of the engine room will be metal, as will the anchor locker bulkhead (sometimes called the crash bulkhead). The aft bulkhead of the main cabin and the forward bulkhead of the aft cabin (at least above the deckline), will all be all metal structures. In our designs, we prefer to install at least some of the bulkheads after the hull is turned over. In most cases, the bulkheads will fall on a frame. It’s no problem to deal with intermediate bulkheads. Some bulkheads will be metal and others are best built of plywood. More recently, especially in powerboats, we have recommended that the sole plating above the engine room be steel as opposed to plywood.
In our designs, the web or solid floors form part of the frame structure. It’s like a mini-bulkhead at each frame. These web floors generally extend up from the keel to the cabin sole, and can be used to contain and divide up tanks and ballast, and to support engine beds. There is no need to ring these web floors with framing bar; in fact, it’s a bad idea because corrosion can form between the bar and the web. The material for the webs should be the same thickness as that used for the flat of the framing; this way, there will be no change in thickness where the framing and the webs are butt-welded to the remainder of the frame.
