Sonar operator

The sonar men resided in the sonar room listening for sounds in the water around the submarine.
A trained sonar technician could through listening recognise different sound sources for instance the difference between turbine and diesel machinery. He could identify different types of propellers.
The bearing could be defined with an accuracy of one degree. To establish target distance you had to plot and perform calculations.

 Submarine U3. Control unit for passive sonar.
U3. Control unit for passive sonar. Photo U3 archives.

The sonar had 48 microphones arranged in a horseshoe configuration in the sonar balcony. The microphones were connected to the sonar unit in the sonar room. A wheel facilitated the technician to decide listening direction.
You could also listen and find direction in the manoeuvring place in the fin.

Here you can listen to sound classified as a 3 bladed 120 rpm cavitating propeller.

Submarine U3 Sonar balcony.
U3 Sonar balcony. Photo U3 archives.

U 3 also had an active sonar used for finding the distance to the target. It could be compared with an horizontal echosounder. Soundpulses could be varied between 10 to 15 kHz.
The active sound generator was located in the forward part of the fin. This unit was rarely used as it revealed the existence of the submarine.

Listen to the ping from an active sonar.

Onboard there were 4 sonar technicians working 2 and 2 in the narrow sonar shack. The carried ships number 5-8. Snr 6 also served as helmsman while Snr 7 and 8 served in the wardroom and petty officers mess.

Submarine U3 Sonar operator, conscript Boström, in action.
U3 Sonar operator, conscript Boström, in action. Photo Rune Nilsson