Hello Apejens, GeoP17,
The patch 1.5.5 changed the propellers to controllable pitch, in accordance of your references (http://80.95.161.114/shipsim/forum/index.php/topic,29071.msg385501.html#msg385501).
I don't know how Steam updates work, but the stock InlandDLC reverts the patch 1.5.5 to 1.5.0, so that 1.5.5 should be re-installed after having installed the InlandDLC. This mistake is probably due to the (wrong) choice of an initial DLC version previous to 1.5.5. Unfortunately, it also lost last minute changes intended to use the now player barges in multiplayer, as well as the Roeier workboat wild behaviour at full rudder/RPM.
The workaround for the version downloaded from the Vstep site has been tested successfully thanks to some Dutch players, but we don't know if it can be used for the Steam versions.
Could you please test this:
After having installed the DLC, having restored patch 1.5.5., the contents of the attached zip should be placed in "C:\Program Files (x86)\Vstep", and Albatross IV should have inwards CPP now, which as you know can be checked by her less favourable turning, just one side ahead without rudder.
If the results are positive, the workaround should make its way through the download both at Vstep and Steam...
Regards,
Luc