Torpedo speed

Gasping for breath, Clark broke the surface of the
water. It had taken all the air in his lungs and more to
move the entire boat without putting too much
pressure on any one part. He'd had to duck under the
rescue ships without moving too fast, or they'd be
complaining about torpedoes again.

[...]

Conspiracy theorists insisted on pointing at the
computer sonar records. Something had come from the
east at a speed of two hundred knots before just
disappearing. This was far faster than most torpedoes,
and the only known weapon capable of moving that
fast was the Russian Squall torpedo, which used
something called supercavitation, that essentially
surrounded the missile with a bubble of air so that
only its nose ever hit water.

The argument was that it could have been
launched from up to twenty miles away. However, the
squall missile was over twenty feet long. The sonar
records that were available indicated that whatever
had been launched had only been two to three meters
in length

Pgs. 40-41