There is perhaps one thing that should be cleared up here, and that is this whole 'double hull' issue.
The Mitsui ship will have have segregated ballast tanks (all tankers built after 1983 have to be fitted with them), which means that her port and starboard sides will have indeed been double hulled, the only single plating being on her bottom.
Double hulls do not, by any stretch of the imagination mean a ship is safer. Indeed, evidence is now beginning to filter out that certain double hull designs have actually caused accidents.
So, unless the ship in distress managed to get UNDERNEATH the Mistui ship in question (her draft would probably be around 20m - so unlikely), then she went straight through a ballast tank and into a cargo tank.
Again, the fact that only 4500 tonnes has been spilt suggest only the upper part of one cargo tank was damaged. On a VLCC, each cargo tank (normally 15 or so in number) carries between 15-18000 tonnes of oil.
Why is everyone so hasty to decry the Master on the tanker without any evidence? He wouldn't have just forgotten his ship was a tanker, nor would he have forgotten that a ship of that size is not the easiest to manoeuvre, especially loaded.
He obviously made that decision for a reason, which I'm sure will come out in the inquiry.
Member would be wise to remember that the media are experts at supressing the truth in exchange for sensationalism, particularly in regards to oil tankers, so I naturally take any report with a pinch of salt. I urge others to do the same.