Good to see so many people on this list ;-)
One important lesson from OSeaM was for me, that the goals and general structure of the "project" (it is not really a project because the end point is not fixed) should be transparent for all participants to avoid many frustrations.
Therefore I would suggest a preamble like (sorry for my english):
"OpenNauticalChart is an initiative with the goal to create a nautical map based on works with free and open-source licences (code, data & map).
The aim of the initiative is to make decisions together with the list (wiki, discource?) as the primary communication channel. To avoid any stagnation a two-thirds majority is required when the discussion strucks."
I am not sure if need any copyrighted services (e.g. the gebco bathymetry layer in OSeaM) in our mapclient.