Figure 10-30. - 3x14 warping tug.

A PONTOON CAUSEWAY consists of an inshore section, an offshore section, and as many intermediate sections as necessary to make up the desired length. Lengths up to 1 mile are considered possible. Each section is a 3x15 structure designed to support a load of 105 tons with a freeboard of 12".

Each string of the offshore (fig. 10-31) and inshore sections (fig. 10-32) is made up of 12 P1 pontoons with a P3 sloped deck pontoon and a P4 ramp-end pontoon at one end At the other end is an end-to-end connection pontoona - a P5F (female) end connection pontoon on the offshore section and a P5M (male) end connection pontoon on the inshore section. Strings of the intermediate sections (fig. 10-33) are made up of 13 P1 pontoons with a P5F at one end and a P5M at the other.

SIDE-LOADED CAUSEWAYS

Causeways, as well as binges, normally are transported to the combat area side-loaded on an LST. bracket on each side of the LST. An LA1 launching angle is bolted to one of the outboard strings of the barge or causeway (fig. 10-34).

The LST is listed far enough to the side being loaded to permit the hinge bar of the pontoon structure to be hoisted onto the shelf bracket. Then the structure is hoisted upright, either by a crane or by the winch(es) on the LST. The hoisting sequence can vary, depending on the gear used and the LST involved.

Regardless of the method use personnel from an amphibious construction battalion, usually with a SWC or BMC in charge, bring the required gear aboard and do the job. The ship's company make necessary preparations aboard ship and provide whatever assistance is required of them.

FLOATING DRY DOCKS

Floating pontoon dry docks are structures consisting principally of a main wharf-like deck and vertical side towers constructed of P-series pontoon units. Pontoon dry docks are submerged by admitting a controlled amount of water into the deck pontoons and raised by expelling the water with compressed air. The tower pontoons act as stabilizers to keep the dry dock level when the deck is under waler. Dry docks require 18' of water in which to submerge the decks 12", the maximum safe submergence, and should be moored in sheltered, quiet water 18' to 20' deep, in an To facilitate this, you should weld a hinge rail or shelf area with a smooth bottom, devoid of large rocks or other obstacles. Two sizes of pontoon dry docks are presently in the ABFC System. This is identified as the 4 x 15 (l00-ton capacity) dry dock. Figure 10-35 shows a 6 x 30 pontoon dry dock installation.

The assembly method of erecting pontoon strings for the dry docks is the same as those used for other pontoons structures. Only P1 pontoons are used and