Hi! I contact you because you changed the coastline. I wonder why this island is natural=coastline:
way/2961222
The way way/35834999
passes it in the north, so it is part of the main island, not in the ocean. I don't know if I should remove the tag natural=coastline from the island or if I should modify the said way so that it passes the island in the south.

Hi!
You used natural=coastline here but the island is in IJmeer, a natural=water.
See natural=coastline
I've removed the tag here:
changeset/64118632
Please check if you find a better tag, else those ways might be removed again.

Hi!
You used natural=coastline here but the Markermeer is a natural=water.
relation/49368
See natural=coastline

Hi!
I just remove a wrong natural=coastline here, don't know what it really is:
way/522081035
Maybe you remember?

I did that quite often now, esp. here:
changeset/64115009
Hope I did not change something good.

Hi! I just changed some ways imported by you where island / islet in fresh water where tagged with natural=coastline. Please check
natural=coastline
before using this tag again.
See e.g. here changeset/64114025

Thanks, I am concentrating on errors in the coastline, just wondered why it is so difficult to the sat images in this areas.
I guess correcting would require some knowledge about tidal changes etc, so nothing I want to do.

Google Maps is not a source we can use.

Hi!
I just stumbled over this natural=water way/410411380
You used landsat as source, Bing and others show the coastline at a very different position. Do you think landsat is up to date?

Hi!
You changed the coastline here in a strange way. Many islands like this
way/584475336
are tagged with natural=coastline and a few days later you created way/585223066
so that all the islands are no longer in the sea.I've removed the natural=coastline tag from those islands, see here:
changeset/64108991

Hi again!
It seems you broke a lot of water multipolygons in this area. What was the reason for the changes?
relation/4133247
relation/4133245
relation/4272563

Hi! You added the tag natural=coastline to some ways here. The ways are inside a natural=water polygon also mapped by you, so I wonder what you did. Please check
natural=coastline
and review my changes:
changeset/64107152

Hi!
I've removed the natural=coastline tag from two ways, see changeset/64105566

Hi!
Please check: You changed a natural=water multipolygon to a aeroway=aerodrome.
The Lake Hood is no longer in the map now.
Is the lake also the Lake Hood Sea Plane Base?

Hi!
Please don't use natural=coastline for island in fresh water. This tag is quite special, see natural=coastline
I've removed those ways and added place=islet to the 2nd ways with natural=bare_rock, and I also added two islets to the water multipolygon
relation/5077
See changeset/64101013
and
changeset/64101109

I've reverted changesets 63960404, 63958383, and this one, see changeset/64092645 and changeset/64092735

Ok, so that means I can remove the name tags from those ways.

Hi!
Please don't add natural=coastline to islets in freshwater. I've removed the tag again. See also natural=coastline

Hi and welcome back to OSM!
You have added a lot of coastline ways here instead of modifying the existing ones. Now there are a huge amount of errors. I think I should revert all those changes.

OK. I did not find that information in the existing data. Always difficult when all sat images still show the stadium ...
Please check what tags the way way/182899509
should have. For sure it is not a coastline, maybe a natural=water?