or end launching and can be used to assure that the string rights itself when launched.

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

Figure 10-25. - Lower angle attachment details using bolt and nut connections instead of tie rods.