Torpedo Practice Head, qualified to 12 kgf/cm² external.

Qualification Test Sequence

The qualification programme follows a defined sequence. Each stage must be successfully completed before proceeding to the next, with inspection witness requirements specified for each test. Overall dimensional measurement is completed first. Fitment trial with the full torpedo assembly — including all piping and sub-assemblies — is then conducted. Internal pneumatic pressure test at 2 kgf/cm² and external hydraulic pressure test at 12 kgf/cm² are performed at the manufacturing facility, each held for 20 minutes across multiple trials.

Following successful pressure tests, the dynamic environment tests are run sequentially: vibration test, shock test and bump test, all as per the qualification test programme. Crack detection by NDT/radiography follows the bump test. Ultrasonic testing is performed after NDT/radiography. Sea water immersion test subjects the assembly to 18 hours of immersion followed by 6 hours outside; no rusting or corrosion is permitted on any part. The buckling test is conducted last — the casing yield strength is validated by subjecting it to maximum pressure until buckling occurs.

Sub-Assembly Details

• Light lamp connection — sealed with ID 107 mm, OD 113 mm, thickness 3 mm O-ring; retained by 10 nos. M6×25 mm Allen bolts
• Hand hole — sealed with ID 143.5 mm, thickness 3.2 mm O-ring; retained by 8 nos. M8×20 mm Allen bolts
• Balloon compartment — retained by 2 nos. M8×18 mm Allen bolts; O-ring as per drawing; hook clamp and stud provision
• Switch connections — two manufactured parts each sealed with O-ring
• Dump valve — retained by 4 nos. M8 Allen bolts with nuts; sealed with ID 41 mm, OD 46 mm, thickness 2.5 mm O-ring
• Drain valve — manufactured cover plate with sealing provision
• Front part cover — 1″ socket and ½″ socket welded; O-ring sealed
• Rear part cover — 1″ socket and ½″ socket welded; O-ring sealed
• Signal flare ejector — studs and nuts; mounting block provision internally

Dimensional Inspection

Overall dimensional measurement is conducted as the first stage of the qualification test programme. Measurement is performed by the manufacturer's representative and witnessed by the inspection authority representative. CMM reports are generated for front and rear flanges confirming conformance to drawing dimensions before proceeding to fitment trial.

Fitment Trial

The fitment trial is conducted with the complete torpedo assembly. All sub-assemblies, piping and fittings are integrated and the practice head is fitted to the torpedo to verify dimensional compatibility and assembly clearances. The fitment trial must be completed successfully before the pressure test programme commences.

Pressure Test Protocol

The internal pneumatic test applies 2 kgf/cm² pressure to the interior of the practice head and holds for 20 minutes. The external hydraulic test applies 12 kgf/cm² externally and holds for 20 minutes. Both tests are conducted across multiple trials with initial pressure and pressure drop after 20 minutes recorded for each trial. Acceptance requires zero pressure drop beyond the allowed tolerance over the full hold duration.