Framing up the hull

The frames were stood up, aligned and tacked onto the jigs angle steels. Its a great feeling to see the 3D shape of the hull for the first time. A string line down the centerline and the spirit level on centreline angle irons (plus plumb-bob) are good tools here. This stage is when you find out if your earlier lofting floor work was accurate or not.

Nicks building jig had angle irons going into cement footings. The hull must be held down onto a secure building jig to resist any plating-up and weld shrinkage forces during hull weld up later on. Initially i thought the heavy railway sleepers might do, but given the expanding clay soil i decided to play 100% safe and make 2 cement footings per sleeper as shown above. The vertical angle iron of the footing is welded to the jig frame and tek screwed into the sleeper. Mixed cement in the barrow. Station wagons shouldn't really be used for this, but it was an old beast with a rusty tailgate.

The transom is set up. This took a bit of bush-geometry and stake into the ground. The transom was pre-fabricated at the frames stage. After oxy-cutting, it wasn't edge peened (like all the other plates were to be) in order to have a natural compound curve left in it. In retrospect it should have been edge peened, to make the sheet flat. The sheet should curve in one dimension only, across the hull. The sheet should be flat to line up with the 2" flat bar end of the keel. (straight angle iron tacked on centreline). In summary I strongly suggest - peen the transom sheet flat before it goes up.

The 40x10 mm stem bar was aligned and tacked into place to form the bow shape. See photo below

Next the 2x 1/4 " flat bar chines were fitted and tacked welded on. I had saved 3.2mm weld rod leftovers for use as spacers between the chine bar and frames. This is done because later on during hull weld up, massive contraction sets in, so the spacers are knocked out as the compressive forces begin. If it were not done the frames would get hugely compressed and start buckling under the load. 

Another problem with flat chine bars is they dont bend too well edge-ways. To bend them like this run a weld bead on the side of bar edge you want the overall bend to go. Suddenly quench the hot weld with water and a curve will form.

 1" flat bar stringers fit into their slots, also with 3.2mm weld rod spacers. All longitudinal framing should have fair curves. If a stringer or chine is too far in,  a small spacer can be tacked on to hold it out to a fair curve.

As soon as the hull framework was strong enough, 4 shade cloths went up over a large bamboo ridge pole. Several angle irons tacked to the keel plates held the ridge pole up. Two more long bamboos held the outer edges.

The stringers and chines were pulled into the transom by tie wires.

The hull shape takes form. The cabin ends at frames 2 and  8 are a little over 20 ft  (6m) apart.

The 1" stringers are located where 3mm thick plates are to go. No stringers were needed to support the bottom plates, at 5mm thick the bottom plates are strong enough on their own. No bilge stringers means fewer potential internal rust traps in this area.