ASSEMBLY OF LAUNCHED STRINGS INTO STRUCTURES

A new method for securing pontoon strings together, referred to as the bolt and nut attachment, has been implemented throughout the pontoon system and completely replaces the heavy tie rod assemblies formerly used. It consists of an A6B bolt and heavy nut connection through holes in the vertical legs of adjoining assembly angles between strings. Special wrenches have been designed to facilitate bilge angle connections while working from the deck, and a two-piece aligning tool is used when hole alignment restricts passage of the bolt. Detailed instructions for using the bolt and nut method of connection to assemble a pontoon structure are presented below.

Figure 10-24.-Angle clamp for assembly of pontoon strings

As each pontoon string is launched, it is brought up alongside the other string(s), lined up, and clamped together with JT2 top angle clamps (fig. 10-24). Insert the A6B bolts by hand through the holes in the vertical legs of the top assembly angles located in spaces between the pontoons, and secure them with the heavy nuts. This is done at every space, starting in the middle and working toward each end. Connections are threaded snug only, at this time, to be tightened later.

After the top bolts and nuts are in place, the bottom angle connections are started. The hole locations and bolting pattern are the same as for the top angles, except that here the special wrenches are used for inserting the bolt, holding nut, and tightening, which is accomplished from the deck side.

Using the JT7 drive wrench, insert the A6B bolt in the holes through the adjoining bottom angles and make contact with the nut being held in position with the JT8 backup wrench. When thread contact has been made, draw up snug but do not tighten until all the bottom bolts have been installed. Again, work from the center out to both ends. (If only one special wrench set is used, start in the center and work each side alternately toward the ends.) When all the bolts have been installed, reverse the wrenches so that JT8 holds the bolt while JT7 drives the nut, and tighten all the nuts to the bolts, top and bottom, to the required torque of 2,400 foot-pounds. Note that the applicable rule is to draw the nut up tight, then turn it about another half turn. (See fig. 10-25.)

The JT13, a two-piece aligning tool, should be used when differences in the hole alignment between angles restrict easy passage of the A6B bolts. The

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 COMPLETE STRUCTURE ON LAND

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.

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