Hi Mateusz, I think it was me who imported the vmap0 data in OSM back in the day. It was so long ago I had to google vmap0 myself. VMAP0 is a global dataset in the public domain (see here: https://gis-lab.info/qa/vmap0-eng.html ). It is very coarse but back then, there was basically nothing in OSM for the subsaharan countries.
Why do you ask?
Cheers, Christian

You could try their mailing list:
https://lists.sourceforge.net/lists/listinfo/openseamap-develop , in the past there have been a lot of discussions about exactly that topic, but well, in the end this monster of a tagging scheme is what came of it :-(.

You basically have to install a JOSM plugin (Seamap editor) to edit those things.

OTOH, the marine mapping stuff really is complicated and manual edits of e. g. a light house is next to impossible. Sometimes there are more than 10 tags to describe the light alone. The tower itself then is another item alltogether. Marine mapping became actually very sophisticated over the centuries.

This conforms with the tagging scheme that is advocated by the Openseamap project.
I know you should not map for the renderer, but only with a seamark:type= something the Openseamap renderer will start to render stuff. The Openseamap renderer is very not very flexible and seems to need these tags to work. The Openseamap tagging scheme is not very OSM like, but it is actually quite wide spread. osm.wiki/OpenSeaMap/Seamark_Objects