RUBBER FENDERS

Anew rubber fendering system for use on pontoon structures has replaced oak timber fenders. Rubber fendering is wing-type, extrusion-shaped, styrene butadiene composition; it is supplied in random lengths to be cut, formed, and fitted in the field for specific structures and operating conditions. For each structure, the fenders, brackets, retainers, and fasteners are furnished in the quantities required. The new fenders absorb enough impact, upon contact with the dock or other structure, to transfer shock from dynamic to static load, thereby protecting both of the impacting structures.

To install rubber fenders, lay out fendering on the deck over the position to be installed. Cut it to the required length, bolt on the retainers and the brackets, and ease it into position, using lines attached. Tack-weld the brackets in place temporarily, remove the lines, and when the entire fender is properly positioned, weld all the brackets as shown on the drawings. Damaged portions can be cut out and repaired with a rubber portion of the same length. Use odd pieces for drop fenders or bumpers. Use a fine-tooth oil-lubricated saw, manually operated or power-operated, for cutting wood or steel bits for drilling holes. Various fendering arrangements and details are shown in figure 10-12. These are subject to change to meet local fendering needs.

H6 HATCH COVER AND FLOOR PANEL ASSEMBLY

Various pontoon structures require a stowage space for tools, chaining, fittings, and miscellaneous gear when not in use. The H6 hatch cover and floor panel assembly (fig. 10- 13) was designed to be installed on any designated pontoon structure and consists of a mounting frame, grating panels, hanger rings, and a 21" diameter, quick-acting, waterproof, flush-mounting, shipboard type of scuttle, together with the parts required to convert a P1 pontoon into a stowage compartment. Making the necessary cutout in the pontoon deck and installing the hatch cover and the other components are done in the field When installed, the hatch cover is a string as the pontoon deck. However, on structures normally traversed by heavy loads, such as causeways and ramp barges, it is advisable to locate the hatch cover away from the regular line of travel-preferably to one side and as far forward or aft as possible-to protect the watertight sealing gasket under the hatch rim.

DECK CLOSURES

Deck closures are used to bridge the openings, or slots, between pontoons while meeting the

Figure 10-13.-H6 hatch cover and floor panel assembly.

requirements for fitting around plates and lift pads. They also can be configured to provide access to assembly angles between structures for wrapping chains and wire rope during causeway beaching and LST side-carry operations. Formerly, five types of closures were needed to perform the necessary functions. These were identified as DC1 through DC5. The DC6 deck closure (fig. 10-14), with certain field alterations, was designed to fulfill all closure requirements and will replace the five closures entirely when stocks of these have been depleted.

The H22 and H23 closure plates are used for joining pontoons and for making bridge-to-wharf or barge-to-wharf connections. The H17AF and H17AM heavy-duty hinges are used to close the deck openings formed by the hinges between the pontoon sections. The closures (fig. 10-15), which are 20" wide and 24 1/4" long, are made from 1/2" steel plate and are used in combinations to fit over and enclose the heavy-duty hinges. Nonskid coating is applied on the top of the closures to prevent slippage. The H22 and H23 closures are not included in the heavy-duty hinge set. They are to be fabricated in the field as required.

BITTS AND CLEATS

Bitts and cleats are steel posts, or arms, to which lines are secured. Structures to be side-carried should have bitts and cleats, as well as all other deck fittings,

Figure 10-14.-DC6 deck closure.

Figure 10-15.-Closure plates H22 and H23.

bolted down on the launching angle side. A typical cleat is shown in figure 10-16. The B1 all-purpose bitt (fig. 10-17) consists of a single 4" diameter post that is 13" long with a 6" diameter cap welded to a base that has two drilled holes for A6B assembly bolts. A 1 1/2" diameter crossarm, 16 1/2" long, runs through the post approximately 10" above the deck. The B1 can be used on all structures requiring a single bitt and can be welded to the deck angles opposite the launching angle side.

The B4 bitt (fig. 10-18) is the same as the B1 bitt except for the base that has been designed for quick positioning in the CP1 chain plate.

Figure 10-16.-Cleat.

Figure 10-17.-Bl all-purpose bitt.

The M147 double bitt (fig. 10-19) consists of two 8" steel pipe posts, 20" long, welded to a 13" x 40" base and capped on the upper ends.

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