It would be good to scratch below the surface with regard to few Bridge watchkeeping practices, some of which are detrimental to keeping of safe lookout or even to obtaining early warning of approaching targets.
Often, one finds the radars set up incorrectly. One sees both radars fixed on a particular range scale, usually 12 nm and 6 nm scales, with target vectors and trails both set on True mode. I have seen even some senior OOWs opting to go with this preference. If the relieving OOW does not challenge it upon taking over watch,then we are looking at more of the same. Innocuous as it seems, what is the potential of harm in this?
Target vector needs to be on Relative mode, and trails on True. While evaluating risk of collision,this gives the OOW an instant appreciation of evolving situation.One might argue that radar is required to have a button to switch vectors from Relative to True, and vice versa, with a single action. This is correct. But only if it is being used systematically, instead of some random interval such as,say, once in 15 or 20 mins.
Likewise, whether in open waters or in busy traffic waters, to leave radars on fixed range scales is to miss approaching targets that lie outside the scale in use completely! By merely switching the radar to,say,24-nm off-centred display, the OOW gets a truly early warning.
If we do not monitor the dynamic situation as it unfolds, we are in breach of COLREGS 5,7a,7b, 7c.
Visual lookout - which is perhaps the single most important collison-avoidance tool - can occasionally suffer due to OOWs watchkeeping position being firmly rooted near the ECDIS and the nearest radar, to the exclusion of all else.
One wasn't surprised to read when a noteworthy statistic emerged from the MAIB's investigations a few years ago : IT WAS FOUND THAT IN 43% OF COLLISION CASES THE OOW WAS EITHER COMPLETELY UNWAWARE OF THE TARGET UPTO THE POINT OF COLLISION, OR ONLY BECAME AWARE WHEN IT WAS TOO LATE TO TAKE EFFECTIVE ACTION TO AVOID COLLISION.
Keeping targets visually sighted is vital. CHANGE IN ASPECT IS MOST READILY APPARENT TO THE HUMAN EYE, BEFORE IT IS TO AN ELECTRONIC DEVICE,SUCH AS AIS OR ARPA, IF TARGET STARTS TO ALTER COURSE. In a close range situation, few seconds of delay in taking correct avoiding action can result in a dangerous situation, as most OOWs know.
Lookout is a shared responsibility but presence of AB on Bridge does not relieve the OOW of his own singular duty to keep proper lookout. OVER TIME, MOST COMPETENT SEAFARERS WILL DEVELOP AN INTUITIVE SENSE OF WHAT IS LIKELY TO RESULT IN CLOSE QUARTERS OR CAUSE A HAZARDOUS SITUATION TO BUILD UP. TOGETHER WITH USING ALL OTHER MEANS TO ASSESS RISK OF COLLISON OR GROUNDING, THIS MAKES FOR THE HIGHEST SKILL A OOW HAS IN HIS REPERTOIRE OF SKILLS !
Simple radar settings,too,can sometimes be terribly skewed. On several occasions I have found the OOW unaware of what the settings are. In one case recently - and this was a senior officer - I found that clutter suppression had been turned up in heavy rain (nothing wrong with that, as long as it is commensurate with prevailing conditions) but the gain control was turned down. This officer had mentioned to me that the radar was 'missing' targets, when I came up on the Bridge. And when proper adjustments were made to the picture, few targets showed up at close range.The OOW explained that he had turned down gain to reduce interference on the diplay!


