I am not really sure about the aim of this project.
If the aim is to host different apps like on www.openstreetmap.de I would like to share an idea.
There are lots of WMS regarding sea information out there and there are also national portals like the german www.geoseaportal.de. With the european inspire directive we will get many data and view services regarding the sea, stream network and lakes.
There are also already free software stacks like http://geonetwork-opensource.org/ or http://opengeoportal.org/software/open-geoportal/ which are designed for collecting metadata and viewing of standardized map services (like WMS).
In my view a global portal is missing for crawling the metadata and viewing of Map Services regarding sea information (or maybe I have overlooked something?) .
One problem would be the internationalization. Mostly the metadata of the services is only written in the national language. A functionality to add also a description in the “language of the web” would be great. But this would be also a lot of work with translation.
I do not have much time since I am focused on my www.opendem.info project, but I would like to contribute something. But perhaps others are also interested.