FREQUENCY OF OVERHAUL

17. During the past several years, experience with the Mark 6 pistol and booster exten-der mechanism has indicated the necessity of periodic inspection, test and overhaul of these components which have been exposed to weather conditions on decks of ships. The design of Mark 6 Mod. 1 pistol and booster extender mechanism inclused seals to keep external moisture from entering the mechanism. Furtermore, all metal parts are treated with polar type rust prevenive compound. It is expected that these measures will materially reduce, if not eliminate, corrosion of working parts provided every effort is made to keep safety covers on the pistols and safety forks on the booster extender me-chanisms.

18. Force afloat should turn in pistols and booster extender mechanisms for inspection, testing and servicing as follows:

(a) Monthly, or oftener if necessary, to stations equipped with Mark 2 Mod. 1 Depth Charge Test Set.

(b) Quarterly, or oftener if necessary, to stations equipped with Mark 3 and Mark 2 Mod. 1 Depth Charge Test Sets.