3. HOW DO SUBMARINERS TRY TO KEEP THEIR POSITION A SECRET?
A submarine underwater is obviously more difficult to find than a ship floating on the surface. But it can still be detected by other vessels from the noises it makes and the magnetic effects caused by its large steel hull, etc. These effects produce a 'signature' for the boat. No two signatures are exactly the same.
Various methods are used to make submarines more difficult to. detect:
ΓÇó sound insulation
ΓÇó locating machinery on vibration cushioning mountings
ΓÇó cladding the outside of the hull with special noise-reducing tiles which reduce the sound energy reflected back to other ships or submarines using SONAR
ΓÇó using radar absorbing materials , important when operating with the periscope masts
ΓÇó energising magnetic coils to neutralise the magnetic fields caused by the submarine (known as degaussing)
ΓÇó carrying detection equipment that tells the crew how much noise their own submarine is making.
Finally, the ocean is made up of different 'layers' that increase in density the deeper the submarine dives. The Sonar readings on a ship hunting a submarine get distorted the deeper the sub dives, so the sub can use these deeper sea layers to avoid detection and remain hidden until the threat has passed. The hunting ship can then be observed safely and appropriate action taken.
