EXPLOSION IN TURRET TWO
Investigation Continued

            prematures.  Thus, for some failure modes at least, an association is apparent between observed out-of-bore prematures and an impending in-bore.  In February 1971 NEWPORT NEWS had three 8” out-of-bore prematures, fired with reduced propellant charges.  Dahlgren chamber pressure-vs-time tests revealed high and erratic 8” propellant pressure peaks with similar reduced charges, and established a high correlation between this propellant abnormality and premature functioning of the BDF (which included a .01 sec firing delay, compatible with the observed NEWPORT NEWS out-of-bore detonation distances).  Subsequent NEWPORT NEWS 8” firings were full charge, pending correction of the reduced-charge abnormality. 

12.           Despite recent emphasis on the need for corrective actions for 5” shipboard prematures attributed to defective sealing of the projectile base, 5” projectiles with missing or gas check seals are still found in the ammunition supply system.  As one example, reference (d) reported 21 defective and 2 missing seals found in a single group of some 4300 5”/38 projectiles.  The circumstances involved for that caliber also have a direct bearing upon the quality of 5”/54, 6” and 8” projectiles with respect to user safety.

13.       Instructions with regard to back-up inspections of projectile base sealing by fleet users appear to have been inadequate.  Current practice appears to have been for ammunition depots to paint the entire projectile base, which makes it impossible for users to see certain documented base seal defects, because they are not permitted to remove the paint.  Further, NAVORDSYSCOM instructions on the subject, reference (e), are not readily available, do not appear to have directive authority in the fleets, and are ambiguously worded.  They are subject only for projectiles obviously damaged in handling.  (The latter interpretation existed in NEWPORT NEWS.)  The Type Commanders’ instructions, reference (f), call for user inspection only for 5” and  6”.  Standard publications such as OP 4 and OP 3347, references (g) and (h), appear to be silent on this subject.

14.       Reference (i) directed a comprehensive (and expensive) program of re-certification inspections of 8” projectiles, including full-length X-ray.  This should assure that projectiles which have passed through this process are as safe as possible with present hardware, subject only to the reservation that those inspections are not able to provide added assurance against a possible BDF hazard, discussed later.  The inspection also yields statistical data on existing discrepancies.

15.       As of 16 November, reference (j), results of the above inspections confirm that there is indeed cause for substantial concern.  With some 14,700 8” HC projectiles inspected, rejections have run nearly 60%.  Many of the rejections are for discrepancies which may be determined, in

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