Papa-class speed and the Spearfish response

Soviet work on titanium produced the exceptionally fast Papa-class submarine, with its top speed variously placed around 44 to 45 knots. The chronology used in the comparison puts Papa in service in 1968 and the Royal Navy's 35-knot Tigerfish in service in 1979. Tigerfish could not provide the speed margin required to pursue such a fast target, prompting the later Spearfish response. Spearfish entered service in 1992; its speed is disputed in the discussion, with figures around 80 knots and higher contrasted with lower claims. At approximately twice the submarine's speed, the torpedo would remove the advantage of trying to escape by speed alone. Papa was still only one vessel, although its development contributed to a further fast submarine class. A claim to the world's fastest submarine had greater public appeal than a faster torpedo, even if the torpedo proved more useful militarily.