How One Ship Caused a Global Traffic Jam

I believe the blocking of the canal was intentionally done and Not an accident, 
The most riskiest part of any journey, trip, voyage and etc. is when you're more alert, whether you are in control of a ship, car, airplane, train, walking through a dangerous neighborhood and etc. In this case the risk is passing through the canal, Ship captains are well experienced especially one in control of a ship this magnitude [the length of the empire state building] he would have been extremely cautious and alert while passing through the canal and would have quickly observed the ship drifting  before it turns sideways, got stuck and completely blocks the canal.