The ASD designation is used to denote the design of any Azimuthing Stern Drive (ASD) Z-Drive tug developed uniquely for Clients in response to a specific set of performance and operational needs. The ASD Designs are designated as ASD "Length"/"Bollard Pull", such as ASD 30/60 (30 metres, 60 tonne BP). This designation is used when the design is not based on one of the more standard classes of tug designs.

ASD 23/40
ASD 23/60
ASD 24/40
ASD 24/45
ASD 24/50
ASD 24/55
ASD 25/40
ASD 26/45
ASD 28/50
ASD 32/60
ASD 34/70