Is this an Emergency Rendezvous Point? I don't know if there's an appropriate way to tag this as a seamark or emergency facility, but there may be something in the documentation linked below.
https://wiki.openstreetmap.org/wiki/Seamarks/Seamark_Objects
https://wiki.openstreetmap.org/wiki/Emergency_facilities_and_amenities

If not, it could be worth asking in the OSM Community Forum.
https://community.openstreetmap.org/