Also seen in this detail are the ends of lapped rode. When two rods had to be joined they were lapped for a minimum length of 250 mm (10"), i.e. 40 diameters and a minimum of three ties were used in this length. At the stem the rods were bent around and welded to the stem pipe as seen in Fig. 13, while at the transom they were hooked around and welded to the transom frame.
Fig. 13 shows the completion of the longitudinal rods and the beginning of the tying in of the vertical rods in the first three frame bays. In Fig. 14 vertical rode are being bent around under the keel pipe and will then be lapped with other rods which complete the circuit of the hull by each vertical rod. A close up of a section of the keel after the horizontal and vertical rods were in place is seen in Fig. 15.
After the completion of this stage, extra longitudinal rods were laid so that the rod Spacing on the keel bottom was 40 mm instead of the 75 mm (3") spacing used elsewhere. In areas of extra stress, such as in the region of bow and sternpooa, additional vertical rods were also tied in to provide extra strength in these areas.
Figs. 16 and 17 show details of sternpost and horntimber , the latter being another section of 40 mm ID pipe braced into place and welded to the correct angle with the sternpost. Note the extra radius in the pipe frame at the stern which is to accommodate the stern tube and still leave sufficient thickness of solid concrete inside the mesh to provide a suitable rigid sternpost. The wooden batten shown in Fig. 16 gives the line of the stern tube, and this was braced in place and cast in situ when pouring the sternpost concrete. Here again, extra rods were added to Provide additional atrength before the fastening on of the mesh.
With the reinforcing rods of the hull in place, the final step before laying the mesh was to weld to the pipe frames a series of lengths of 50 x 50 mm (2 x 2") angle iron. The purpose of this angle iron was threefoid: firstly to provide a finishing line for the construction and casting of ferro-cement floors designed to reinforce and strongly tie together both sides of the hull; secondly to provide fixation points for removable wooden planks which would provide the flooring in each compartment of the hull; thirdly to act initially as convenient supports on which to place the temporary planking which would be necessary during the process of meshing and plastering. It is very important that supports be provided for workmen at this stage to avoid distortion of the hull during the plastering stage. Fig. 18 shows this stage iron in place. In the background can be seen the cut-away sections of the floors provided in the region of the engine bearers. Figs. 20, 21 and 23 show this in greater detail at later stagee.
3.5 Tying of the mesh layers
Mesh was fastened to the inside of the hull first. Four layers were laid from bulwark to keel vertically, and tied in place with just sufficient ties to hold the mesh taut against the reinforcing .rods. The mesh used was in rolls of 45 m (150 ft) long by 0.9 m (3 ft) wide and this was cut to suitable lengths. Joins between adjacent widths were made by laps 75-100 mm (3-4") wide, cure being taken to stagger the laps from one layer to the next so that at no place was there a build up of more than 4 layers of mesh plus the additional layer of one lap. Too many layers concentrated at one place would cause an increase in thickness above the average, as well as making it difficult to force the mortar through the accumulation of mesh layers. This inside mesh was wrapped closely around the pipe frames and tightly tied in place, enclosing the pipe'frames.- Fig. 19 gives a close-Up of a section of the hull with the four inner layers tied in place.
Note that the spacing of the vertical rods to the right of the pipe frame in Fig. 19 is at 50 mm (2") centres instead of the usual 100 mm (4") centres. This close-up is of an area in the bow which has been given additional reinforo to allow for the greater stress on the relatively flat sections in this area, when the vessel is driving into a head sea.