Essentially the pilot steered towards two marks on the chart which he thought marked the centre of the channel. In fact they marked the bridge tower.
IMO, that's oversimplifying it by a long shot!
The report indicates that he was generaly disoriented. He should have recognized the landmarks in his own area of operation on radar, and shouldn't have even been relying on the electronic chart to navigate (the ship wasn't set up for it). In any case, he should have recognized the symbols, as they are the same on systems that ARE used to navigate!
In it's conclusions, the report lists "the pilot’s degraded cognitive performance from his use of impairing prescription medications," as the first of several probable causes of the accident. He was a mess!
Having said that, the report also reveals a reactive (as apposed to proactive) system, that allowed him to keep working as a Pilot. Traffic Control also failed to provide guidance when it perceived his course was incorrect, limited partially by lack of equipment due to budget constraints. Lots of "Shoulda, Coulda, Wouldas" here!
The cost to repair the Cosco Busan alone was over $1,800,000 (cheap, as most of it was done in China). The relatively minor bridge repair was in excess of $1,000,000 (imagine if he hit the bridge head on, doing ten knots!). Factor in all the other accident related costs, and I have to wonder how cost effective it was not to provide proper Coast Guard medical supervision, or provide Traffic Control with state of the art equipment (as only two examples).
Which brings me back on topic. I can envision a similar report after a collision with the rocks, saying: "Lowering the rocks or marking them with navigational aids had been considered. However, due to budget constraints......" I mean really. How much would it cost to put a couple of buoys out there?