Maritime Autonomous Surface Ships (MASS) and the COLREGS: Do we need quantified rules or is “the ordinary practice of seamen” specific enough?

Maritime Autonomous Surface Ships (MASS) is currently on the agenda in several countries and also in the IMO. In Norway a 120 TEU container feeder is being build and will start sailing autonomously in 2022. The challenge is huge. One question is whether or not the present, quantitative, collision regulations needs to be updated to rules where expressions as “early” and “substantial” are quantified? Or if ships can sail autonomously under the present rules? Another question is if MASS should be marked to signal that the ship is in autonomous mode? Or if it is enough that she follows COLREGS? This discussion paper will take a closer look at these questions and advocate automation transparency, meaning that the behavior of an autonomous vessel has to make sense and be understandable to human operators on other manned ships and crafts.