C-Shield stands for 'Combined System for Harbour, Infrastructure and Littoral Domains'. It is a project which is designed to operate with various aspects of small boats to watch: sensing, marine cockpit, communications, mission management and autonomous navigationt. This lecture is about the communication. For this we assume that a number of maritime platforms opertate jointly network centric. The problems that this entails, and a solution (Maritime Manet) will be discussed. Then the results of a demonstration of Maritime Manet on the IJsselmeer will be discussed.