Information overload is often a big problem for new third mates when they encounter heavy traffic. A typical difficult situation might involve two or three large ships, a few fishing boats and maybe a tug and tow all moving a different speeds
Finding a solution to traffic problems can be done by the bridge watch either entirely by visual means,entirely with electronic aids such as ARPA (radar) or along the spectrum between the two. When the ship is in zero visibility there is no visual information available the bridge watch must work entirely at the radar end of the radar/visual spectrum. In clear weather an experienced deck watch officer or pilots might maneuver in traffic without the use of radar at all.
Most commonly however in clear weather, in heavy traffic most bridge watch officers will find themselves relying mostly on visual information but using the radar/ARPA as an aid to verify or confirm what they see out the window.
Not so however for the new third mate.
From a gcaptain post Technology on Ships Can be Dangerous, Warns P&I Club
In another case cited by the club, the OOW decided to use the Automatic Radar Plotting Aid to track 99 different ships whilst transiting a congested anchorage and to overlay the radar image with Automatic Identification System data. With so much information being displayed, he failed to notice that one of the targets had both a minimal closest point of approach (CPA) and time to CPA and, ultimately, there was a collision.This doesn't surprise me. When a new third mate attempts to solve a difficult traffic situation, most new watch officers do not trust solutions "by eye" but prefer instead the precision provided by radar/ARPA almost as if they were in zero visibility.
I've gone up to the bridge in traffic to find the mate switching from radar to radar each one with different mix of features trying to solve a problem that can be solved by a more experienced mate in just seconds by eye.
In aviation new pilots must first learn to fly a plane using visual flight rules and then later gaining an instrument rating.
The key to improving the ability of a new mate to deal with traffic is to increase his/her confidence in solutions found by eye with radar/ARPA confirmation. That sometimes means prying them away from the radar and demonstrating to them how traffic problems can be solved by looking out the window.