HBT (MN 10/77).

Both funnels are black with white “HBT”. H131 stacks the letters vertically, while H132 places them together horizontally; the choice depended on the individual funnel’s size.

The red flag has a white cross with a blue diamond wholly contained at its centre. An NSU pennant was flown above it. The source describes the flag as the reverse of Smit-Lloyd’s.