In the early surface battles of 1942–43, Japanese destroyers and cruisers were able to launch their torpedoes from about 20 km (11 nmi; 12 mi) at the unsuspecting Allied warships attempting to approach to gun range. The American, Australian, and New Zealand warships were expecting enemy torpedoes to be fired at less than 10 km (5.4 nmi; 6.2 mi), their own typical torpedo range. The many torpedo hits suffered by Allied warships in such engagements led their officers to the belief that these torpedoes had been fired from Japanese submarines operating in concert with the surface warships. On rare occasions stray very long-range Type 93s struck ships much further away than their intended targets, leading the Allies on occasion to suspect their ships had been mined. The capabilities of the Type 93 went mostly unrecognized by the Allies until one was captured intact in 1943.
There were many opportunities to figure out that the Japanese torpedoes had much, much range of Allied ones, but the inference that torpedo hits were all from hidden submarines rather than superior technology may have been reasonable. Apparently, it took until after a torpedo was captured to figure it out.
Possibly the Type 93:
There were many opportunities to figure out that the Japanese torpedoes had much, much range of Allied ones, but the inference that torpedo hits were all from hidden submarines rather than superior technology may have been reasonable. Apparently, it took until after a torpedo was captured to figure it out.