CAULKING JOINTS

A riveted joint basically is not watertight or oiltight because the surfaces or edges that are held together are not machined or ground. Therefore, the riveted joints or boundaries tend to loosen from the shock of gunfire, collision, vibration, explosion, and rocking of the ship as a result of high-speed maneuvering. Repairs to this type of damage are usually made by caulking the loosened

joint. These repairs must be made as soon as defects are discovered. In caulking, a thin fin of metal is usually sprung from the baseplate or structure by using

a pneumatically driven chisel, caulking tool, or hammer. The general procedure for caulking a riveted joint is illustrated in figure 7-8.

SHORING

Shoring is often used aboard ship to support ^{ruptured decks,} to strengthen weakened bulkheads and decks, to buildup temporary decks and bulkheads against the sea, to support hatches

and doors, and to provide support for equipment that has broken loose.

Knowing when to shore is a problem that cannot be solved by the application of any one set of rules. Sometimes the need for shoring is obvious. Examples are loose machinery or damaged hatches. However, dangerously weakened supports under guns or machinery may not be so readily noticed. Although shoring is sometimes done when it is not really necessary, the best general rule is this: If in doubt, shore it.

SHORING MATERIALS

The basic materials required for shoring are shores, wedges, sholes, and strongbacks. A shore is a portable beam. A wedge is a block, triangular on the sides and rectangular on the butt end. A shole is a flat block that may be placed under the end of a shore to distribute pressure. A strongback is a bar or beam of wood or metal which is used to distribute pressure or to serve as an anchor for a patch. The strongback is often shorter than a shore.

Many other items are used in connection with shoring. They include wooden battens, claw hammers, mauls and sledges, handsaws, mattresses, pillows, axes, hatchets, wood clamps, chain falls, electric welding machines, oxyacetylene cutting outfits, cold chisels, wood chisels, nails, wooden plugs, packing sheets, turnbuckles, screw jacks, hydraulic jacks, bolts, nuts, and washers. The COSAL lists the quantity of such gear that each ship should carry on board.

Figure 7-7.-Materials used in assembling a folding T patch.

Figure ^{7-8.-Cau1king a riveted joint.}

Shores

The best woods available for shores are Douglas fir and yellow pine. Hemlock and spruce may also be used. However, they are not as good because they are not as strong. Any wood used for shores should be straight grained and relatively free of knots and cracks. Green timbers are not as strong as cured timbers. If it is necessary to use a poor quality wood, use more shores than would be required for shores of a better quality wood. Shores authorized for shipboard use are treated with a fire-resisting chemical. They should NEVER be painted with an ordinary paint.

The length of a shore in use should never be more than 30 times its minimum thickness. Thus a shore that is 4 by 4 inches should not be any longer than 10 feet. A shore that is 6 by 6 inches should not be any longer than 15 feet. A shore that is 4 by 6 inches should not be longer than 10 feet. The shorter the shore is in relation to its thickness, the greater the weight it will support. Shores should normally be carried aboard ship in 16-foot and 18-foot lengths that can be cut to the required lengths when needed.

Wedges

Wedges should be of softwood, preferably fir or yellow pine. They should be cut with a coarse saw and left rough and unpainted. This allows the wedges to absorb water and hold better than if they are smoothed or painted. A few hardwood wedges should be kept on hand for special uses, since they resist crushing better. However, hardwood wedges cannot be used for all shoring because they have a tendency to work loose. When hardwood wedges are used, they must be checked frequently.

Wedges should be approximately the same width as the shores with which they are used. They may be made with various angles at the leading edge, but a blunt wedge will not hold as well as a sharp one. A wedge should be about six times as long as it is thick. Thus a wedge to be used with a shore that is 4 by 4 inches should be about 4 inches wide, 2 inches thick, and 12 inches long. Figure 7-9 illustrates some wedges and shows how they are used.

Sholes

Sholes should be made of Douglas fir or yellow pine planks that are at least 1 inch thick and 8 to 12 inches wide. Wider sholes can be made

Figure 7-9.-Wedges.

Figure 7-10-Use of a shole.

by nailing cleats across two or more widths of planking. A single plank may have to be cleated at the ends to keep it from splitting. Do not fabricate sholes in advance of the actual need for them; prefabricated sholes would probably not fit where they are needed. The use of a shole is illustrated in figure 7-10.

Strongbacks

All or part of an ordinary shore may be used to make a strongback. Shoring scraps should be

kept for use as strongbacks and short shores. Heavy planks, steel bars, angle irons, and pipe can also be used as strongbacks (fig. 7-6).