Nautical Chart Data in Maps

Anyone know how to actually get the nautical chart information to show up in the Maps activity? I’m sitting offshore learning (ok, playing with) my watch and I can’t seem to get buoys to show on it. I’ve got it set for “Marine Chart Mode” in settings, but I’m not sure what I’m doing wrong from there.

I also tried downloading an OpenSeaMap format file from bbbike.org to get my chart info as a custom map, but my fenix doesn’t seem to want to open it.