PRINICPAL PARTS

1. CASES FOR MK 6, MK 6 MOD. 1, MK 7, AND MK 7 MOD. 1 depth charges are alike ex-cept for the minor details noted below and differences in dimensions.

MARK 6 AND MARK 7 CASES

2. The Mk 6 and Mk 7 deoth charge cases are steel cylinder closed at the ends by steel heads welded in place. Set in each head of each case is an opening, closed by a pipe plug, through which TNT is loaded into the case. A central tube, extending longitudinally through each case, houses the pistol and booster-extender. Blank covers are provided to close the central tubes during shipment or whenever the pistols and booster-extender are not installed.

The desing of these cases has been modified as follows:

(a) One vent fitting installed near the filling hole in each head. This feature was added to allow air to escape when TNT is poured into the case. The vent plug must be screwed tightly into place when loading is completed.

(b) Circumferential bead adjacent to ends of case eleminated. This was done to permit use of the Mark 6 case in British depth charge release tracks.

3. To conserve critical material galvanized finish of cases has been discontinued. Cases are now finished as follows:

(a) All surface parkerized.

(b) Interiror surface painted with 1 coat projectile cavity paint.

(c) Exterior surfaces and central tube painted with 1 coat zinc chromate primer.

(d) Exterior surfaces painted with 1 coat dark grey paint.