This paper presents a communications and software architecture in support of Prognosis and Health Monitoring (PHM) applications for renewable ocean-based power generation. The generator/turbine platform is instrumented with various sensors (e.g. vibration, temperature) that generate periodic measurements used to assess the current system health and to project its future performance. The power generator platform is anchored miles offshore and uses a pair of wireless data links for monitoring and control. Since the link is expected to be variable and unreliable, being subject to challenging environmental conditions, the main functions of the PHM system are performed on a computing system located on the surface platform. The PHM system architecture is implemented using web services technologies following MIMOSA OSA-CBM standards. To provide sufficient Quality of Service for mission-critical traffic, the communications system employs application-level queue management with semantic-based filtering for the XML PHM messages, combined with IP packet traffic control and link quality monitoring at the network layer.