Lessons learned: Lookout warns but OOW does not check

TIN news:   MARSThe Nautical Institute has issued Mars Report No 38/2014 regarding OOW not checking lookout warnings.
 
While underway on a general cargo vessel, the OOW was listening to music on a personal computer and, from time to time, he hummed or sang along with the music and chatted with the lookout. The visibility remained good and they could not see any ships or other traffic nearby. The S-band radar, AIS unit and both very high frequency (VHF) radios were switched on. Shortly after 2100, the lookout reported a white light fine on the vessel's port bow. The OOW told the lookout that the light was a distant lighthouse some 30 miles away. About 18 minutes later, the lookout reported that the white light he had seen earlier was flashing. The OOW could see no radar targets in the general direction of the light and told the lookout that it was the distant lighthouse that he had previously mentioned. At 2142, the lookout reported a green light fine on the port bow. The third mate thought the green light was from an expected isolated danger beacon and he responded to the lookout that the light was a distant ‘light buoy'. In fact, the green light was the starboard sidelight of a sailboat underway, about 4 miles ahead and on a collision course with the vessel.
 
At about 2149, the sailboat's AIS unit ‘target alarm' sounded. Alerted, the skipper's wife called the skipper to come inside the cabin and have a look at the AIS display. Together, they noted from the AIS data that the approaching ship was making good a course of 122 degrees (T) at 11.5 knots. The skipper then went back on deck to look for the ship. Within a minute, he saw its green sidelight fine on his starboard bow. The skipper decided to alter course to port to a heading of about 280 degrees, with the aim of passing well clear of the ship.
 
Just after 2153, the cargo vessel's lookout reported that the green light he had been observing seemed very close. The sailboat was in fact now less than one mile ahead of the ship and the two vessels were closing at a combined speed of nearly 18 knots. In response to the lookout's report, the OOW checked the radar and the AIS unit but saw no target in the direction of the green light. About two minutes later, the sailboat called the vessel on VHF channel 16 and identified themselves. The yacht was now about 200 m from the ship's bow. Alerted by the unexpected radio call to his ship, the OOW stopped humming. A few seconds later, he broadcast on VHF channel 16 that the ship's course was being altered to starboard. He then ordered the lookout to engage hand steering. He could no longer see the yacht's green light when he ordered the rudder hard-to-starboard. At 2156, with the vessel's heading at about 130º, it collided with the sailboat, the yacht scraping along the ship's starboard side.
 
When the Master came to the bridge after the collision, one of his first actions was to adjust the radar gain and clutter controls. The yacht (as a target) was then easily identified on the radar display. Had the OOW correctly adjusted the controls on the ship's radar, he may have determined that the green light the lookout had identified was a vessel. As a result, he would have been in a better position to make a full appraisal of the situation, the risk of collision and to take early and appropriate action.