INSPECTIONS OF CASES

10. Inspect a depth charge case as follows:

(a) Remove the metal shipping covers.

(b) Inspect the case and central tube for TNT exudate leaks. Exudate is a dark brown oily liquid which separates out from cast TNT and may exude from the cases after a pe-riod of storage. While modern methods of refining and loading TNT virtually eliminate any possibilty that such exudate will be found, it must be remembered that this exudate is highly inflammable and must be handled accordingly. If any traces of exudate are found on depth charges, wipe them off with waste (or similar material), using carbon tetrachlo-ride as a solvent if necessary. Alkali and all soap type cleaners should not be used. Dis-pose of the waste with due regard for the inflammability of the exudate.

Blue indicates exterior - Red indicates interior

(c) Check the diameter and length of the case to see that they are with in the specified tolerances.

NOTE: Each Mark 6 and Mark 6 Mod. 1 case shall pass through a ring gauge having an internal diameter of 17.70 inches, plus or minus .010, and a length of not less than 4.0 inches. Activities undertaking to gauge depth charge cases should use a gauge having an internal diameter conforming as closely as possible with the maxi-mum limiting dimension.

Metal procurement difficulties have made it necessary to allow some manufacturers more liberal tolerance on the length of the case. It will be found that the length of some cases are 3/16 inch short of the required nominal dimension of 27.625 inches.

(d) Check to insure that the ends of the cases are not deformed so as to prevent rolling in depth charge release tracks. Manufacturing specifications require that each case shall roll evenly and smoothly upon a gauge consisting of a pair of parallel rails, each rail hav-ing a horizontal bearing face width of not less than 3.0 inches and a vertical guide face not less than 3.0 inches high. These horizontal and vertical faces should form an angle of 90' and meet in a sharp corner. The distance between the inside faces of the two verti-cal guides shall be 27.70 inches, plus or minus .020 inches. Test rails shall be level in a crosswise direction, and inclined along their length at an angle of between three and five degrees. Test rails shall be not less than six feet long to allow for at least one complete revolution of the case during its passage along the test rails unassisted.

(e) Cases in service which have slight exterior deformations may be used provided the functioning of the case in release tracks, roller loaders and projectors is not impaired. Badly deformed or leaky cases should be returned to depots for reconditioning or dispo- sed of as circumstances require. The charge must be removed from damaged loaded ca-ses before attempting extensive repairs.

(f) Inspect the central tube and see that it has no projections or deformations which will interfere with motion of the booster can or proper assembly of the pistol or booster ex-tender. Check the dimensions of the tube with a cylindrical plug gauge having a diameter of 4.160 inches (plus .003, minus .000) and a length of 8.75 inches (plus or minus .030). This gauge should enter and pass freely through the length of the central tube.

(g) Inspect the tapped holes in the flanges at the end of the central tube.

(h) Inspect and clean the gasket seats on both ends of the case to be sure that the assembly can be made watertight.

(i) Inspect the gasket and see that they are in good condition.

(j) Inspect empty cases for leaks. Cases must hold an internal air pressure of 20 pounds per square inch without leaking. If welding is required, check dimensions after completing the welding.