Spearfish was designed to outrun fast submarines

What is probably the fastest conventional torpedo?

Spearfish, officially rated above 60 knots and designed with the fast Alfa-class submarine in mind.

The exchange asks which conventional torpedo is fastest. The answer is probably Spearfish, with official figures of more than 60 knots and about 54 kilometres, or 29 nautical miles, of range. Higher speeds have been attributed to it, although those claims remain separate from the official specification. The design logic was to produce a weapon fast enough to catch the Soviet Alfa class, with roughly twice the submarine's speed.