An advanced weapon when introduced, by the outbreak of World War II advances in aircraft would have made it obsolete but for the introduction of the high-velocity round and new director designs. It was intended that the curtain of fire it threw up would be sufficient to deter attacking aircraft, which it did, but was hampered by the ineffective Mk III director. The MK IV Director with a Gyro Rate Unit and Type 282 radar was a great advance and was introduced on the "King George V"-class battleships. In January 1941, ′s Mk VIII (HV) mountings performed flawlessly firing 30,000 rounds with very few stoppages. When was attacked and sunk by Japanese aircraft near Singapore, the subsequent report judged that a single 40 mm Bofors gun firing tracer was a more effective anti-aircraft weapon than a multiple pom-pom in director control, as the pom-poms did not have tracer ammunition and the pom-pom ammunition had deteriorated badly in its ready use lockers, while the Type 282 radar units also failed in the equatorial heat. In the same action, the Commissioned Gunner of spent the whole action running from one pom-pom mount to another trying to keep them operational due to the faulty ammunition. The pom-poms on "Repulse" shot down two of the four confirmed kills made by Force Z, while "Prince of Wales" pom-poms did record hits on enemy aircraft.