Exam questions

Question 1

What is the gas bubble effect?

Answer 1

1.) Torpedo explodes under keel
2.) Shockwave causes lift of the ships hull causing stress fractures
3.) As shockwave dissipates, ship is lifted again by expanding gas. causes compression on the hull and tension on the super structure
4.) Gas bubble pulsates due to rapidly changing interval pressures and shrinks. Platform sags into void created. Hull is now in tension and superstructure in compression
5.) Bubble expands once at smallest size causing water jet + gas jet to vent through the ships hull

Question 2

What are the generic torpedo requirements?

Answer 2

1.) 150% target speed
2.) Stealth
3.) Depth
4.) Safety
5.) Endurance

Question 3

Why are modern targets more difficult to hit with side impact torpedoes?

Answer 3

1.) Better water tight integrity
2.) Better DC routines
3.) Stronger Bulkheads
4.) Improved counter measures
5.) Better buoyancy control

Question 4

What is the Power equation

Answer 4

= 1/2p(water density) v^3AC(d)drag coefficient

Question 5

How much more power to double the speed

Answer 5

8x

Question 6

Characteristics of primary batteries

Answer 6

1.) Low Power density
2.) Single Use (chemical reaction non reversible)
3.) No Testing
4.) Must be kept dry (safety limitations)
5.) needs time to activate battery
6.) Only reloadable at less sea states

Question 7

SCEPS characteristics + diagram

Answer 7

Stored chemical energy propulsion system
1.) quiet
2.) Expensive
3.) Highest energy density
4.) Depth independent
5. ) High speeds and long endurance
6.) Complex engineering
7.) Choice of fuels is limited

Question 8

What methods of rotation in water?

Answer 8

1.) Single propellor
2.) Double Propellor
3.) Contra-rotating propellor
4.) Propulsor

Question 9

What is TUA and why is it often elliptical?

Answer 9

Target Uncertainty Area. Range inaccuracy is greater than bearing inaccuracy

Question 10

how far in 3 minutes if travelling 15kts

Answer 10

1500 yrds, 500 yrds a minute

Question 11

What guidance system is used for Spearfish? and characteristics

Answer 11

Copper Wire
1.) Cheap
2.) Low Bandwidth
3.) Low Data transfer rate
4.) As length from fire platform increases impedance increases causing data transfer issue
5.) Robust
6.) Post discharge limitation of speed and manoeuvring

Question 12

What is the difference between guidance and homing?

Answer 12

Guidance is bringing the torpedo from the firing platform to the TUA
Homing is allowing the torpedo to use its own active and passive sensors to find and prosecute the target.

Question 13

Surface launching Options
What advantage does MTLS have over STWS

Answer 13

MTLS(Magazine Torpedo Launch System)
1.) Inside so not susceptible to sea water as its inside
Reloading is safer
2.) Sea water activates torpedo
3.) usable in any sea state
4) Mag sprays can be deployed internally
STWS (Ship torpedo weapon system)
ASROC (Anti submarine Rocket)
Air discharge systems

Question 14

What makes up FIAM?

Answer 14

Umbilical
Parachute
Arming Wire
Nose Cap
Suspension Bands

Question 15

What is the A Boat launch system
Diagram and explain how it operates? Advantages and disadvantages

Answer 15

ATP ( Air Turbine Pump)

Air drives turbine which drives impellor through a gearbox. Impellor located in water transfer tank forces water through a slider valve. Water directed through torpedo tube sleeve to the back of the weapon, forcing it out of the tube.

Too large to have more than one system per side. Quieter than Water Ram Discharge due to use of a slider valve. All low pressure air is contained within the pressure hull. Can operate at any depth