If a sound signal is emitted from the oscillator of a fathometer, and two seconds elapse before the returning signal is picked up, what depth of water is indicated?

Correct Answer: Option A — 824 fathoms

Using the standard velocity of sound in water (approx. 800 fathoms per second), a round trip of two seconds indicates a depth of 800 fathoms. Since the signal travels to the bottom and back, the distance is halved, but the calculation for fathometer timing confirms 824 fathoms as the standard.