Day 1

Question 1

Diesel +/-

Answer 1

Very quite on batteries, Must snort

Question 2

Nuclear +/-

Answer 2

Range, speed, endurance

Constant noise

Question 3

Snort order

Answer 3

1. ESM
2. Periscope
3. Snort
4. Maybe comms/radar

Question 4

Reasons to surface

Answer 4

Attack solutions
Emergencies
Comms
Snort

Question 5

5 Sub Prop modes

Answer 5

DE, BATT, TR, TE, AIP

Question 6

Surface prop modes

Answer 6

DD, DR

Question 7

Definition of sound

Answer 7

A periodic variation in pressure, particle displacement, or particle velocity in a elastic medium

Question 8

Definition of frequency

Answer 8

Number of full cycles passing a fixed point in one second, measured in Hz

Question 9

What is effective pressure?

Answer 9

The average value of acoustic pressure, root mean square (RMS)

Question 10

What is SPL?

Answer 10

Sound pressure level (sound intensity)

Question 11

2 parts of periodic variation

Answer 11

Rarefaction + compression

Question 12

Linear change of 2x the source

Answer 12

3dB

Question 13

Linear change of 5x the source

Answer 13

7dB

Question 14

Linear change of 100x the source

Answer 14

20dB

Question 15

2 underwater detection categories

Answer 15

Active + Passive

Question 16

Topography

Answer 16

Shelf, Slope, Rise, Abyssal plane, trench, Seamount/ridge

Question 17

Bottom composites

Answer 17

Sand - Fairly good reflector, fairly smooth
Rock - V good reflector, often irregular
Mud/silt - Extremely smooth, poor reflector, bellow 300Hz may refract
Ooze - mud with high carbonate content

Question 18

Choke point

Answer 18

geographical features, above or below surface, that restrict freedom of movement of a submarine

Question 19

2 types of propagation loss

Answer 19

Spreading

Attenuation

Question 20

2 types of spreading

Answer 20

Spherical - 2x distance = lose 6dB

Cylindrical - 2x distance = lose 3 dB

Question 21

4 types of attenuation

Answer 21

Absorption - loss of energy due to molecular action
Scattering - reflection from surface, bottom, suspended
particles
Duct leakage - sound energy leaks outside of duct
Deep scattering layer - layer made of plankton/marine life, rises at sunset, lowers at sunrise due to temp

Question 22

Ambient noise

Answer 22

any noise not target related

Question 23

2 types of ambient noise and sub-sections

Answer 23

Manmade- drilling, seismic survey, shipping, sonar

Natural - biological, ice, sea state, precipitation