I know I've screwed up and/or missed things. Most memorable was crossing the mouth of the Columbia river at night, dodging the incoming and outgoing traffic. There was a brightly lit "something" ahead and to starboard, but quite far away. And a small return on our radar more or less on the same bearing. I decided the brightly lit blob was an on-shore facility of some sort, and radar return a boat which I continued to monitor.
ARPA showed the boat target clear of us, at least most of the time, but it was erratic. This went of for maybe 20-30 minutes and the darn small boat kept getting closer and closer, though still showed as clear most of the time. I was looking for its nav lights, but couldn't spot them, so assumed it was a small boat with lights lost in the sea state.
Then came the oh-****. Turns out the big lit up facility was a fishing boat with all it's deck lights on, and was one in the same with my small radar target. The deck lights completely drowned out the boats nav lights, and we were on a direct collision course with me as the give way vessel.
Lessons learned:
- you can't judge the distance of lights at night. Not even close.
- even though a boat needs to display nav lights and nothing else that might confuse the same, boats don't comply
- Simrads ARPA doesn't work and creates more danger rather than reducing it.
I got way with it in this instance, but could just as well have become a statistic at the bottom of the sea.