BAAC Flashcards
Define sound underwater
The movement of sound causes a change in the pressure of the medium (water) in which it travels.
Wave motion
When a body vibrates in a medium it produces a series of COMPRESSIONS and RAREFACTIONS, whose wavelength depends on the speed of the vibration
Speed of Sound in WATER?
1500 m/s
List 6 types of power plants?
Diesel; Steam turbine; Gas turbine; Nuclear; Air independent Propulsion (AIP); Combinations of above
Four stroke engine cycle
Intake. Compression. Combustion. Exhaust
ERPM
Engine Revolutions Per Minute
Speed of sound in AIR
340 m/s
Define Reduction Ratio
Is the ratio between the engine speed before the reduction and the propeller speed after the reduction
Two types of reduction stages
Single stage and multi stage reduction
Define Mesh rate
The noise created by meshing gears is at a frequency consistent to the number of teeth meshing in one second
What is CODOG?
Combined Diesel or Gas
What is CODLAG?
Combined Diesel Electric and Gas
Four factors for propeller design
Diameter. Blade Twist. Pitch. Slip
6 propeller categories
Fixed pitch. Variable pitch. Controllable pitch. Water jet. Pump jet. Pods
Two types of power generation
AC or DC
