Found something that might add to this thread while looking for ship plans:

This is Dutch ship "Java", from NV Stoomvaart Maatschappij 'Nederland' - photos are from 1939 (peacetime colors) and in unspecified time during the war:

https://www.marhisdata.nl/image.php?...edf23f5f&opt=5

https://www.marhisdata.nl/image.php?...18165bfb&opt=5

From their posters, funnel colors should be black top, yellow bottom. What is visible here is that while ship was entirely painted grey, funnel is still in two different colors, with separation line between them matching pre-war one (possibly different shades of gray?)

Edit: BTW, was there any documented case of ships belonging to neutral countries sailing camouflaged and darkened? It would be helpful to know this for implementing proper colors in SH5, because clones keep "borrowing" textures from their parent ships, leaving modder a choice between having some camouflaged neutrals in convoy or lots of uncamouflaged combatants with navlights on. The former situation would be of course preferable, but was there any such case in real life?

The aircraft could probably be a Martin Maryland, which doesn't solve much as it was used by both the Vichy French and the British.

I would bet on British nationality because of the white spot on the tail, but not a certainty.

Yes, that's correct. Lloyd's Book of House Flags and Funnels also gives the same color combination.

If you look closely, king posts and masts display the same scheme. My guess is that their tops had the same color as hull and superstructure, while the bases were painted in a darker shade of grey. That might have made them lesser distinguishable from far away, when their silhouettes were the only visible part of the ship against the light background of the sky.

I have read reports of neutral vessels having been attacked by U-boats because they were darkened at night, because they were zig-zagging, because they were sailing where they shouldn't (according to German restrictions), because they lacked neutrality markings and their nationality wasn't otherwise clearly distinguishable, and because of... human error. So yes, darkened neutral ships were a thing, but from the game perspective they should be set as valid targets (i.e. they should be placed in "free" national rosters).
As for camouflaged neutral merchants, I can't neither confirm nor discard them, but I think the best "camouflage" for neutral vessels would have been displaying their national flag and neutral markings as clearly as possible. This is so true that they retained those marking even when sailing within Allied convoys. See the convoy sketches posted by iambecomelife in this thread for an example of that.

If no better solution is found, I think we could make the grey skin standard :hmmm:

Thank you for your feedback JapLance :salute:

Or maybe Free French :hmm2:

https://i.imgur.com/z1N87de.jpg

That's why I think it's a British Maryland:

https://i.imgur.com/nn2X8OA.jpg

The Free French Maryland you showed has the white parts in the rudder, further back.

:salute:

You are probably right about the plane. I wish we could id the ship on the background. She is peculiar in having one or maybe two large funnels. She looks like a late 30s passenger ship converted as a troopship :hmm2: