The magnetic field induced in the floating structure is dependent on the potency of the Earth’s magnetic field and the layout and direction of floating structure w.r.t. the Earth’s magnetic field. As discussed earlier, The ship’s induced magnetism is also a cause of the ship’s magnetic field just like the ship’s permanent magnetism. Ships are normally a huge floating structures continuously counteracting the Earth’s magnetic field. Whenever a conductor moves in a magnetic field, its cuts the magnetic lines of flux. Hence the conductor induces an appreciable amount of voltage in it. As the ship’s outer layout isn’t homogeneous in structure, it is why dissimilar amounts of voltage are inducted at various positions in the ship’s body. This difference in voltages results in the flow of a current through the ship’s body. This in turn creates a magnetism which is known as Ship’s induced magnetism. This induced magnetic field can be resolved into following :
This field component of Ship’s induced magnetism acts downwards when the ship’s position is in North-side of Magnetic-Equator and upwards whenever the ship’s position is in South-side of Magnetic-Equator.
When a ship heads towards the North/south heading, the horizontal-induced-field-component of magnetic field of the Earth induce a fore & aft or longitudinal field component. This field component of Ship’s induced magnetism is known as Longitudinal-induced-field-component.
Note : Whenever the longitudinal-induced-field-component and athwartship-induced-field-component are combined together, It forms the Horizontal-induced-field-component.
Whenever a ship’s heading is eastwards, a magnetic effect implies on the ship’s structure in athwart line. Its left area (Port) becomes north-pole of an imaginary magnet. Likewise, its right area becomes the south-pole. This field component of Ship’s induced magnetism is known as the Athwartship-induced-field-component. The strength of its magnetism is dependent on the extent of latitude of Horizontal-induced-field-component.
Left side of the ship is called Port side and right side of the ship is called starboard side in marine terminology.