JT13 is inserted anywhere along the strings (preferably in the center) and drawn together tightly, using the JT7 and JT8 drive and backup wrenches. Leave the aligning tool installed, remove the JT7 and JT8 wrenches, and complete connections of the bolts and the nuts, after which remove the aligning tool and replace it with a bolt and nut. Lanyard rings, provided on wrenches and two-piece aligning tools, must always be used to safeguard against loss.
As each string is secured with the bolt and the nut to the preceding string(s), installation of AP4A plates, pad eyes, chocks, cleats, and other accessories required for the structure and not previously installed on the strings are welded or bolted in position as specified in the detailed drawing. To complete the assembly, skip-weld the deck closures in the slots of the deck.
Assembly of a complete structure on land is begun in the same manner as construction of strings, except that the structure is assembled parallel to the shoreline on rails perpendicular to the shoreline. Structures up to three strings wide can be built in this manner by assembling the second and third strings on top of the first. When built this way, the bolt and nut attachment previously described and the assembly plates are installed as the work progresses. KPl keeper plates are welded on the bottom A6B assembly bolts and accessories. They will not interfere with launching and can be attached to the assembly. Portable scaffolding, fabricated in the field and similar to that shown in figure 10-26, is attached to the pontoon assembly angles and can be moved to other locations on the structure to meet construction progress. The completed structure can be side-launched by sliding it out to the ends of the rails and tipping it into the water.
A barge is any of several pontoon string assemblies connected together to form a complete unit used for transporting cargo, including vehicles and personnel, and used primarily in their transfer from landing craft to amphibious vehicles or for lighterage duties in ship-to-shore movement of cargo. Barges, designed for lighterage operations, either self-propelled or towed, can be built in various sizes and, with modifications as required, can be used as a diving platform for salvage operations, as a tugboat, as a gate vessel, for fuel storage, or for mounting cranes.
The intended use of the barge determines the length of the strings, the number of strings needed, and the pontoon configuration of each string. Seven standard-size barges in the P-series equipment include
Figure 10-26. - PortabIe scaffolding used in assembly of structures on a pier.Continue Reading