No time to Familiarize

Own vessel was outbound from Boston (USA), in the TSS approaching the precautionary area off Nantucket Shoals. The weather was calm with dense fog and visibility less than fifty meters. Speed about 12 knots, lookout posted, whistle blowing, two ARPA's running, etc. Except for two small stationary targets well to port, the only other target on the radar was right astern with a speed of about 19 knots and overtaking us. The ARPA s fairly consistently gave a CPA of less than one cable on our port side. When this large target had closed to less than two miles without showing any signs of taking avoiding action, own vessel made a large, seventy degrees, alteration to starboard. At about the same time the target reduced speed rapidly to about 9 knots and altered course to port, now passing across our stern at about one mile. We returned to our original course and the target increased speed and moved out into the precautionary area. Soon thereafter, the target itself made a large alteration of course to starboard, having presumably reached a navigation waypoint. A close quarters situation was once again had developing, with the same target now crossing from port to starboard at 19 knots and with a CPA of substantially less than one mile. This was just too much, as I believe that manoeuvring any vessel at speed in the open sea in nil visibility, at distances counted in meters instead of miles, is totally unacceptable, no matter what electronic aids one has available. We elected to take a long slow round turn to starboard to give the guy all the sea room he wanted.

Now I have a confession to make. This occurred last year. My OOW and I had just joined our vessel at Boston the day before and we had not yet fully familiarized ourselves with the newly installed AIS, which was a stand-alone unit not linked to the radars. The fact that the daylight reflecting on the small display screen made it almost impossible to read is no excuse. If we had utilized the potential of the AIS, we would have known that the target, one of the newer and larger passenger cruise ships, was bound for New York, and was therefore likely to be altering course to starboard to head in that direction upon reaching the end of the TSS. It might have been wiser for us to make our very large alteration to port instead of to starboard, but even with hindsight I am not sure. With a known identity, we could also have initiated a VHF conversation to discuss intentions, but then so could our target vessel (though I do not subscribe to the US practice of arranging all passing of vessels by VHF, which is fine in their inland waterways but has always had the potential for disaster in the open sea with unknown vessels.