A stable equipment label did not mean the anti-submarine set had stopped changing. One manual described the destroyers as carrying the same ASDIC type even while the system evolved. Other references used different numbers and codes to separate those versions. Specification tables can therefore hide incremental changes in naval electronics.
Notable Point · 11:12-11:33
ASDIC changes hidden by a stable type label
One manual gave successive destroyers the same ASDIC type label even though the equipment continued to evolve and other references distinguished the changes with finer codes.