Further to Ian Thomas comment below referencing Handytankers fleet....Handytankers is one of the largest pool managers for modern double hull chemical product tankers (25/50M DWT range). Members of the pool include Maersk, Saarland, Motia, Chemikalien, etc.
Having said that, it still doesn't explain the "black/ vs blue hull" on some Maersk tankers.
BTW....Nice uploads by both Ken Smith & John White. Crisp, sharp features of what appears to be a well maintained ship.

You informed many of us with this shot John! Supported by Webmaaster Ken Smith with the immediately previous uploaded pic of her.

Does that mean they're the 'black sheep' of the Maersk fleet? (No pun intended). Or does it signify they're charter vessels?

The Maersk Misumi is another black hulled tanker.
www.shipspotting.com/gallery/photo.php?lid=2068896

The Maersk Maya and her other two sisters the Maersk Mikage and Maersk Murotsu are managed by Fuyo Kaiun Co. Ltd., Japan for Maersk and all three are in the Handytankers fleet.


Regards
Ian Thomas

No it is unusual to see a Maersk tanker with a black hull
regards
john

I take it Maersk don't always stick to their standard blue colour then judging by this picture?