According to typical Sommerfeld Hertz vector

the electromagnetic field expressions are derived when horizontal DC current element is located in air half-space and seawater half-space respectively.Based on the result

the induced electric field of vessel moving across geomagnetic field is derived on the basis of transient state continuity theory.Take one Japanese missile destroyer for example

the magnitude and spatial distribution characteristics of its induced electric field are analyzed.The result indicates that the magnitude of electric field is several millivolt per meter at about five meters from hull when the vessel sails at a velocity of 20kn.According to the analysis

the induced electric field of vessel moving across geomagnetic field can be measured for certainty and its spatial distribution has apparent characteristics.