Interactive echo ranging
Echo Depth Sounder
Cruise the ship, ping the deep, and chart an ocean you cannot see. Every echo that comes back is one depth reading.
Echo log is empty. Fire a ping.
0 m/s
One ping can answer three times: whatever hangs in the water first, then whatever sits on the bottom, then the bottom itself. Map 90% of the floor and identify all three contacts to complete the survey.
One ping, many echoes
Every reflector in the beam answers on its own schedule. Depth is d = 1500 × t / 2: a school at 60 m answers in 80 ms, a floor at 300 m takes 400 ms. Nearer things always speak first.
Reading the trace
Each received echo plots one dot below the ship's position. Ping after ping, the profile of the bottom draws itself. This is exactly how survey ships chart an ocean no one can see.
The ultrasound bridge
Swap seawater for soft tissue at 1540 m/s and the round trip becomes about 13 microseconds per centimeter. Your machine plots reflectors the way this chart plots the floor.