OPERATIONS AND MAINTENANCE INSTRUCTIONS

ILLUSTRATIONS:

4 Dr. 434309 - Inlet valve cover and wrench assembly.

5

Page 97:

Paragraph 15:

Delete the last sentence, "A good grip with the thumb and forefinger applied at the rim of the cover will be sufficient to form a tight seal."

Add paragraph 15(a) as follows:

New type safety covers, figures 1 and 2, and wrench for applying same, figure 3, will be available for issue to the service about 1 October 1944. It is intended that these covers shall replace existing types now in use. Obsolete covers should be scrapped.

The improved features of these covers are as follows:

(a) Knurled rim to facilitate application and removal.

(b) Indentations in knurled rim to receive wrench lugs. The wrench is to be used to assu-re proper cover tightness.

(c) Wax impregnated rubber gasket to reduce friction and thereby permit better sealing.

(d) Reinforced top surface of knobbed cover to prevent buckling of the top when knob contacts the depth charge release track stripped plate.

When attaching and removing the safety covers, it may be necessary to hold the index pointer of the Pistol Mark 6 with the depth setting wrench as shown in figure 4,or with fingers, to pre vent moving the pointer off the depth setting by application of torque to the cover wrench.

It is believed that this precaution will not be necessary for Pistols Mark 6 Mod 1 and Mark 6 Mod 2 because index pointer rotation is retarded by friction of the watertight seal in the dial plate.

There will be two chief sources of supply for inlet valve covers and wrenches: Naval Mine Depot, Yorktown, Virginia; and Naval Ammunition Depot, Hawthorne, Nevada. Main and Secondary Stations as defined in NAVORD M7-44 are authorized to requisition a sufficient number of these items to comply with the following:

(a) Covers - for attachment to pistols recovered by these activities.

(b) Wrenches - for use at the activities and for issue to ships for which pistol inspection and test service is ordinarily rendered. The initial issue of wrenches to be one wrench for each depth charge station on DD's, DE's, and PF's; and two wrenches per ship for other vessels. Additional wrenches may be requisitioned to maintain a reasonable surplus for initial emergency issue and for replacement.

All ships carrying Depth Charge Pistols Mark 6, Mark 6 Mod 1, or Mark 6 Mod 2 should receive valve covers and wrenches direct from the Main and Secondary Stations noted above without reference to the Bureau of Ordnance.