Based on the features and limitations of maritime communication in the associated areas, this paper focuses on the key technology of wide-band communication network at sea under E-navigation framework. New methods and strategies to realize wide-band communication as well as some issues to be tackled for ensuring its development had been addressed. Especially, the WiMAX (Worldwide Interoperability for Microwave Access) technology is applied to set up an offshore network infrastructure. An routing mechanism based on packet store-carry-and-forward was carried out to solve the problem of the intermittent network connectivity in overocean communications. Based on the system modelling, the problem description, and the time-capacity-mapping, the algorithms are given to maximize the packet weight as the resource optimization goal.