Complex sentence: By 19 October 1943, when the "Aversa" was sunk, "Ultor" had fired 68 torpedoes of which 32 were hits (47%), the highest proportion of hits made by any submarine Commander up to that time.
Split into simpler sentences: By 19 October 1943, when the "Aversa" was sunk, sixty eight torpedoes had been fired of which thirty two were hits (47%). This was the highest proportion of hits made by any submarine Commander up to that time.