15-12-2013, 01:45 PM
The modern system is used to identify ships by the underwater sounds made by the engines and props.
These are dipped into the water from helicopters or fitted to submarines and can identify the engine type and gear ratio to the prop and the number of blades.
Diesel/electric propulsion is used on some types of war ship in order to make this more difficult.
They have even sold war ships to the enemy and then been able to listen for them when there is trouble and they know exactly what they are listening for.
These are dipped into the water from helicopters or fitted to submarines and can identify the engine type and gear ratio to the prop and the number of blades.
Diesel/electric propulsion is used on some types of war ship in order to make this more difficult.
They have even sold war ships to the enemy and then been able to listen for them when there is trouble and they know exactly what they are listening for.
