On a marine craft that may be equipped with plural outboard motors engine control nodes can be mounted on outboard motors, and a display control node, as well as the network management node can be connected to a bus constructing a network. Receiving a display transmission frame sent out by the engine control nodes, display control node distinguishes the number of engines mounted, determines display layout compatible with the number of engines, and displays navigation information such as engine operational information, and navigation data including boat speed and others on a navigation information display meter in accordance with the determined display layout.