Despite all the money spent and articles written.
More than a half century later later, the wreck of U-864 was found in 2003 by the Norwegian Navy, two miles off Fedje. It was discovered that the cargo of poisonous liquid mercury had been slowly seeping from the flasks into the surrounding ocean. After spending fifteen years evaluating the risks of raising the wreck and its dangerous, unexploded torpedoes, in February 2017 the Norwegian government finally “entombed” the broken submarine with a half-meter of sand and 160,000 tons of rocks to prevent further contamination, thus forming a cairn for the German submarine that had met its terrible fate under unique circumstances.
The Hunt for Red October dramatized for the public one of the tensest forms of warfare imaginable: combat between submarines submerged deep under the ocean’s surface, the nerve-wracked crews scouring the fathomless depths for their adversary’s acoustic signature using hydrophones.
However, while hunting undersea enemies is one of the primary jobs of modern attack submarines, only one undersea sub engagement has ever taken place, under decidedly unique circumstances.
This is not to say that submarines have not sunk other submarines. Indeed, the first such kill occurred in World War I, when U-27 sank the British E3. Dozens other such engagements occurred in the two world wars. However, in all but one case, the victims were surfaced, not underwater.
This was foremost because the submarines of the era needed to spend most of their time on the surface to run their air-breathing diesel engines; they could only remain underwater for hours at a time with the power they could store on batteries, moving at roughly one-third their surface speed. Therefore, submerged action was reserved for ambushing enemy ships and evading attackers.
There were additional problems intrinsic to having one submarine hunt another underwater in an era that predated advanced sensors and guided torpedoes: how could submerged subs detect each other’s position? During World War II, submarines came to make greater use of hydrophones as well as active sonar; however, the latter models could only plot out a submarine’s location on a two-dimensional plane, not reveal its depth.