For those that still need the helo's in the port of Rotterdam: ARC Endurance is not inbound yet. Currently inbound and approaching Zeebrugge from Bremerhaven.
And all choppers are still easily visible from Waalhaven Noordzijde, as seen by me this afternoon. A few are readable, the rest you can count tails and rotor heads and some noses etc.
It is in the link I copied above my comment "still moored in Zeebrugge"... On the right side of that page you can see "latest position". You can also zoom in to its exact position in port.