A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: John Brown
Date: 2015 Apr 20, 01:59 -0700
Different ships, different long splices - of course. Slight thread drift coming up, apologies.
You mention the experience of survivors being passed by ships with apparently vacant bridges. This comes up regularly in reports from yachts of close quarters situations with ships; again with "nobody on the bridge". Having seen this from both view points I would say that unless a ship's watchkeeper is actually on the bridge wing, rather than in the wheelhouse, close to the instruments, controls and comms, it is virtually impossible to see whether anyone is there or not. In my experience it is rare for a ship's bridge to be left unmanned for even a couple of minutes.
Possible failures of the lookout to detect survivors in the water or in very small vessels is another matter. Assuming no radar target is detected (quite possible with poor target responses, sea and rain clutter) a visual sighting is all important. Unless actively searching the sea surface, the natural focus of a lookout's attention is on the horizon, where most other marine traffic is first seen. Small freeboard objects, including liferafts are virtually invisible at, say, ten mile range. When they are closer, between the ship and the horizon, they are sometimes difficult to detect from the height of a ship's bridge against a background of breaking waves, particularly with yachts' hulls and sails often being white in colour. The prescribed visible range of yachts' nav lights also needs a rethink.