Airplanes are pretty darn automated (big ones). But when they are flying, they are also in direct control of air traffic control on the ground. This solves lots of issues with them running in to each other.
Out in the open water, there isn’t anybody in control like ATC. Humans use judgement to make decisions. What if one ship approaching has Asian programming and the other has Western Euro and a third has USA…and somebody mixed up the units of measurement. Will it crash like the Mars lander?