OpenEarth is a free and open source initiative to deal with Data, Models and Tools in earth science & engineering projects, currently mainly marine & coastal. In current practice, research, consultancy and construction projects commonly spend a significant part of their budget to setup some basic infrastructure for data and knowledge management. Most of these efforts disappear again once the project is finished. As an alternative to these ad-hoc approaches, OpenEarth aims for a more continuous approach to data & knowledge management. It provides a platform to archive, host and disseminate high quality data, state-of-the-art model systems and well-tested tools for practical analysis. Through this project-superseding approach, marine & coastal engineers and scientists can learn from experiences in previous projects and each other. This may lead to considerable efficiency gains, both in terms of budget and time. The following 2 papers describe the OpenEarth approach in more detail: Terra et Aqua, 2013, NCK 2012 & WODCON 2010.