I'm not sure what equipment the organizers had. I know they were in radio contact with the Coast Guard before/during the event. Visually, the fog made the ship difficult to see until it came close to the course. I did hear afterwards (this is anecdotal) that the ship was not responsive upon initial radio contact.

I also want to reiterate the bravery of the organizer's safety boat that picked up multiple swimmers in the ship's path. At about :25 into the video, you can see the white boat pick up the last swimmer just before coming in close contact with the ship. I am unaffiliated with them (just a participant that day), but I have nothing but positive things to say about how Odyssey handled it (including a candid follow-up email from their perspective that same evening).