On some ships if you walk onto the bridge at near the end of the watch there is a good chance you will find the mate bent over the chart table writing up his log while the lookout is busy making a pot of coffee. Not my ship of course, but the point is this: don't bet your life upon the fact that a big ship doing 20+ knots is keeping a good lookout.
Consider the story of the fishing vessel Dictator which was fishing for scallops with about 50 other boats in
heavy rain and fog, visibility of only about a half-mileThe story is here from Fishermans Voice Container Ship Hits Fishing Boat by Laurie Schreiber
The wheelhouse watch never saw the ship coming until it was almost on top of them:
All I saw was this great, big, huge ship going down the side of us,” he said. “Water was coming over the stern from his wake, and he squirted us out from under his bow.”I don't know what was happening on the bridge of the container ship, the watch might not have been paying attention or they may have lost the return from the Dictator in the sea clutter, or it might have been time to put on a fresh pot of coffee. Either way the crew of the Dictator was placing their lives in the hands of the watch aboard another vessel.
AIS (Automatic Identification System) may have prevented this incident. Had the Dictator been transmitting an AIS signal it may have been seen aboard the container ship. That solution however still relies upon the vigilance of another vessel. One possible solution might be a receive only AIS. The devices are inexpensive, there is a good article at Boating SF - Get AIS Ship Tracking on your boat.
Don't bet that yours is the only vessel not keeping a proper lookout.