Hi Salty,
Luc has beaten me to giving you an answer! The "ASD" term means Azimuth Stern Drive, the drive system is similar to "Bugsier 2" but with the drives aft of midships near the stern.
http://forum.shipsim.com/index.php/topic,21677.msg394736.html#msg394736
@ Rbsanford,
The barges ARE part of the DLC. So there are three new ships plus 5 barges in differing states of loading. Pictures below show control unit on foredeck, barge under way with nav. lights & barge altering course using onscreen control. The drive for the barges is up forward so that the control operates in the same way that "B 2" does.
Regards,
Angus.