A boat steering system provides an operator with excellent efficiency and an excellent operation feel during direction guide member deflection by considering and making adjustments based on a running status of the boat. A block of OFDM symbols is transmitted from multiple antennas over multiple sub-carrier frequencies. A second electrode of the light emitting element is connected to a third power supply line selectively connected to a voltage source from which an arbitrary positive voltage is supplied or another voltage source from which 0 V is supplied. The combination of cationic surfactants and phosphate esters in this invention not only form very stable emulsions in water, but, surprisingly, also form extremely stable emulsions in concentrated liquid fertilizers, including 32-0-0 fertilizer.