Function
There is some misunderstanding of the mechanism of detection of submarines in water using the MAD boom system.
Magnetic moment displacement is ostensibly the main disturbance, yet submarines are detectable even when oriented parallel to the earth's magnetic field, despite construction with non-ferromagnetic hulls. For example, the
Soviet-
Russian Alfa class submarine, whose hull is constructed out of
titanium to give dramatic submerged performance and protection from detection by MAD sensors, is still detectable.
The Alfa's detectability has led some analysts to deduce that the MAD's name is an intentional deception, so effective that the
Soviet Union decided to construct the Alfa and even consider building the
Typhoon class submarine SSBN out of titanium at one point. Since titanium structures are detectable, MAD sensors do not directly detect deviations in the earth's magnetic field. Instead, they may be described as long-range electric and electromagnetic field detector arrays of great sensitivity.
An
electric field is set up in conductors experiencing a variation in physical environmental conditions, providing that they are contiguous and possess sufficient mass. Particularly in submarine hulls, there is a measurable temperature difference between the bottom and top of the hull producing a related
salinity difference, as salinity is affected by temperature of water. The difference in salinity creates an
electric potential across the hull. An electric current then flows through the hull, between the laminae of seawater separated by depth and temperature.[
citation needed]
The resulting dynamic electric field produces an electromagnetic field of its own, and thus even a titanium hull will be detectable on a MAD scope, as will a surface ship for the same reason.
